diff --git a/ghwt.py b/ghwt.py
index 493b1e2ff..bb0be706a 100755
--- a/ghwt.py
+++ b/ghwt.py
@@ -52,8 +52,8 @@ def unpack(sproj, branch, outdir):
         return 1
     spdir = os.path.split(outdir)[0]
     ofilename = os.path.join(spdir, config['wrap-file']['source_filename'])
-    ofile = open(ofilename, 'wb')
-    ofile.write(us)
+    with open(ofilename, 'wb') as ofile:
+        ofile.write(us)
     if 'lead_directory_missing' in config['wrap-file']:
         os.mkdir(outdir)
         shutil.unpack_archive(ofilename, outdir)
diff --git a/mesonbuild/backend/backends.py b/mesonbuild/backend/backends.py
index 82b387d79..54be8ec1d 100644
--- a/mesonbuild/backend/backends.py
+++ b/mesonbuild/backend/backends.py
@@ -139,24 +139,34 @@ class Backend():
         langlist = {}
         abs_files = []
         result = []
-        for src in unity_src:
-            comp = self.get_compiler_for_source(src, target.is_cross)
-            language = comp.get_language()
-            suffix = '.' + comp.get_default_suffix()
-            if language not in langlist:
-                outfilename = os.path.join(self.get_target_private_dir_abs(target), target.name + '-unity' + suffix)
-                outfileabs = os.path.join(self.environment.get_build_dir(), outfilename)
-                outfileabs_tmp = outfileabs + '.tmp'
-                abs_files.append(outfileabs)
-                outfileabs_tmp_dir = os.path.dirname(outfileabs_tmp)
-                if not os.path.exists(outfileabs_tmp_dir):
-                    os.makedirs(outfileabs_tmp_dir)
-                outfile = open(outfileabs_tmp, 'w')
-                langlist[language] = outfile
-                result.append(outfilename)
-            ofile = langlist[language]
-            ofile.write('#include<%s>\n' % src)
-        [x.close() for x in langlist.values()]
+
+        def init_language_file(language, suffix):
+            outfilename = os.path.join(self.get_target_private_dir_abs(target),
+                                       target.name + '-unity' + suffix)
+            outfileabs = os.path.join(self.environment.get_build_dir(),
+                                      outfilename)
+            outfileabs_tmp = outfileabs + '.tmp'
+            abs_files.append(outfileabs)
+            outfileabs_tmp_dir = os.path.dirname(outfileabs_tmp)
+            if not os.path.exists(outfileabs_tmp_dir):
+                os.makedirs(outfileabs_tmp_dir)
+            result.append(outfilename)
+            return open(outfileabs_tmp, 'w')
+
+        try:
+            for src in unity_src:
+                comp = self.get_compiler_for_source(src, target.is_cross)
+                language = comp.get_language()
+                try:
+                    ofile = langlist[language]
+                except KeyError:
+                    suffix = '.' + comp.get_default_suffix()
+                    ofile = langlist[language] = init_language_file(language,
+                                                                    suffix)
+                ofile.write('#include<%s>\n' % src)
+        finally:
+            for x in langlist.values():
+                x.close()
         [mesonlib.replace_if_different(x, x + '.tmp') for x in abs_files]
         return result
 
@@ -215,13 +225,11 @@ class Backend():
 
     def serialise_tests(self):
         test_data = os.path.join(self.environment.get_scratch_dir(), 'meson_test_setup.dat')
-        datafile = open(test_data, 'wb')
-        self.write_test_file(datafile)
-        datafile.close()
+        with open(test_data, 'wb') as datafile:
+            self.write_test_file(datafile)
         benchmark_data = os.path.join(self.environment.get_scratch_dir(), 'meson_benchmark_setup.dat')
-        datafile = open(benchmark_data, 'wb')
-        self.write_benchmark_file(datafile)
-        datafile.close()
+        with open(benchmark_data, 'wb') as datafile:
+            self.write_benchmark_file(datafile)
         return (test_data, benchmark_data)
 
     def has_source_suffix(self, target, suffix):
@@ -442,7 +450,8 @@ class Backend():
         mfobj = {'type': 'dependency manifest',
                  'version': '1.0'}
         mfobj['projects'] = self.build.dep_manifest
-        open(ifilename, 'w').write(json.dumps(mfobj))
+        with open(ifilename, 'w') as f:
+            f.write(json.dumps(mfobj))
         d.data.append([ifilename, ofilename])
 
     def get_regen_filelist(self):
diff --git a/mesonbuild/backend/ninjabackend.py b/mesonbuild/backend/ninjabackend.py
index 595feddce..e81c407b6 100644
--- a/mesonbuild/backend/ninjabackend.py
+++ b/mesonbuild/backend/ninjabackend.py
@@ -133,17 +133,18 @@ class NinjaBackend(backends.Backend):
         self.all_outputs = {}
         self.valgrind = environment.find_valgrind()
 
-    def detect_vs_dep_prefix(self, outfile, tempfilename):
+    def detect_vs_dep_prefix(self, tempfilename):
         '''VS writes its dependency in a locale dependent format.
         Detect the search prefix to use.'''
         # Of course there is another program called 'cl' on
         # some platforms. Let's just require that on Windows
         # cl points to msvc.
         if not mesonlib.is_windows() or shutil.which('cl') is None:
-            return outfile
-        outfile.close()
-        open(os.path.join(self.environment.get_scratch_dir(), 'incdetect.c'),
-              'w').write('''#include<stdio.h>
+            return open(tempfilename, 'a')
+        filename = os.path.join(self.environment.get_scratch_dir(),
+                                'incdetect.c')
+        with open(filename, 'w') as f:
+            f.write('''#include<stdio.h>
 int dummy;
 ''')
 
@@ -157,9 +158,8 @@ int dummy;
         for line in stdo.split(b'\r\n'):
             if line.endswith(b'stdio.h'):
                 matchstr = b':'.join(line.split(b':')[0:2]) + b':'
-                binfile = open(tempfilename, 'ab')
-                binfile.write(b'msvc_deps_prefix = ' + matchstr + b'\r\n')
-                binfile.close()
+                with open(tempfilename, 'ab') as binfile:
+                    binfile.write(b'msvc_deps_prefix = ' + matchstr + b'\r\n')
                 return open(tempfilename, 'a')
         raise MesonException('Could not determine vs dep dependency prefix string.')
 
@@ -167,30 +167,31 @@ int dummy;
         self.interpreter = interp
         outfilename = os.path.join(self.environment.get_build_dir(), self.ninja_filename)
         tempfilename = outfilename + '~'
-        outfile = open(tempfilename, 'w')
-        outfile.write('# This is the build file for project "%s"\n' % self.build.get_project())
-        outfile.write('# It is autogenerated by the Meson build system.\n')
-        outfile.write('# Do not edit by hand.\n\n')
-        outfile.write('ninja_required_version = 1.5.1\n\n')
-        outfile = self.detect_vs_dep_prefix(outfile, tempfilename)
-        self.generate_rules(outfile)
-        self.generate_phony(outfile)
-        outfile.write('# Build rules for targets\n\n')
-        [self.generate_target(t, outfile) for t in self.build.get_targets().values()]
-        outfile.write('# Test rules\n\n')
-        self.generate_tests(outfile)
-        outfile.write('# Install rules\n\n')
-        self.generate_install(outfile)
-        if 'b_coverage' in self.environment.coredata.base_options and \
-            self.environment.coredata.base_options['b_coverage'].value:
-            outfile.write('# Coverage rules\n\n')
-            self.generate_coverage_rules(outfile)
-        outfile.write('# Suffix\n\n')
-        self.generate_utils(outfile)
-        self.generate_ending(outfile)
+        with open(tempfilename, 'w') as outfile:
+            outfile.write('# This is the build file for project "%s"\n' %
+                          self.build.get_project())
+            outfile.write('# It is autogenerated by the Meson build system.\n')
+            outfile.write('# Do not edit by hand.\n\n')
+            outfile.write('ninja_required_version = 1.5.1\n\n')
+        with self.detect_vs_dep_prefix(tempfilename) as outfile:
+            self.generate_rules(outfile)
+            self.generate_phony(outfile)
+            outfile.write('# Build rules for targets\n\n')
+            for t in self.build.get_targets().values():
+                self.generate_target(t, outfile)
+            outfile.write('# Test rules\n\n')
+            self.generate_tests(outfile)
+            outfile.write('# Install rules\n\n')
+            self.generate_install(outfile)
+            if 'b_coverage' in self.environment.coredata.base_options and \
+                    self.environment.coredata.base_options['b_coverage'].value:
+                outfile.write('# Coverage rules\n\n')
+                self.generate_coverage_rules(outfile)
+            outfile.write('# Suffix\n\n')
+            self.generate_utils(outfile)
+            self.generate_ending(outfile)
         # Only ovewrite the old build file after the new one has been
         # fully created.
-        outfile.close()
         os.replace(tempfilename, outfilename)
         self.generate_compdb()
 
@@ -202,7 +203,8 @@ int dummy;
             jsondb = subprocess.check_output([ninja_exe, '-t', 'compdb', 'c_COMPILER', 'cpp_COMPILER'], cwd=builddir)
         except Exception:
                 raise MesonException('Could not create compilation database.')
-        open(os.path.join(builddir, 'compile_commands.json'), 'wb').write(jsondb)
+        with open(os.path.join(builddir, 'compile_commands.json'), 'wb') as f:
+            f.write(jsondb)
 
     # Get all generated headers. Any source file might need them so
     # we need to add an order dependency to them.
@@ -505,8 +507,8 @@ int dummy;
         self.generate_subdir_install(d)
         elem.write(outfile)
 
-        ofile = open(install_data_file, 'wb')
-        pickle.dump(d, ofile)
+        with open(install_data_file, 'wb') as ofile:
+            pickle.dump(d, ofile)
 
     def generate_target_install(self, d):
         should_strip = self.environment.coredata.get_builtin_option('strip')
@@ -1416,16 +1418,22 @@ rule FORTRAN_DEP_HACK
             # but those are really rare. I hope.
             if not compiler.can_compile(s):
                 continue
-            for line in open(os.path.join(self.environment.get_source_dir(), s.subdir, s.fname)):
-                modmatch = modre.match(line)
-                if modmatch is not None:
-                    modname = modmatch.group(1)
-                    if modname.lower() == 'procedure': # MODULE PROCEDURE construct
-                        continue
-                    if modname in module_files:
-                        raise InvalidArguments('Namespace collision: module %s defined in two files %s and %s.' %
-                                               (modname, module_files[modname], s))
-                    module_files[modname] = s
+            filename = os.path.join(self.environment.get_source_dir(),
+                                    s.subdir, s.fname)
+            with open(filename) as f:
+                for line in f:
+                    modmatch = modre.match(line)
+                    if modmatch is not None:
+                        modname = modmatch.group(1)
+                        if modname.lower() == 'procedure':
+                            # MODULE PROCEDURE construct
+                            continue
+                        if modname in module_files:
+                            raise InvalidArguments(
+                                'Namespace collision: module %s defined in '
+                                'two files %s and %s.' %
+                                    (modname, module_files[modname], s))
+                        module_files[modname] = s
         self.fortran_deps[target.get_basename()] = module_files
 
     def get_fortran_deps(self, compiler, src, target):
@@ -1433,27 +1441,32 @@ rule FORTRAN_DEP_HACK
         usere = re.compile(r"\s*use\s+(\w+)", re.IGNORECASE)
         dirname = self.get_target_private_dir(target)
         tdeps= self.fortran_deps[target.get_basename()]
-        for line in open(src):
-            usematch = usere.match(line)
-            if usematch is not None:
-                usename = usematch.group(1)
-                if usename not in tdeps:
-                    # The module is not provided by any source file. This is due to
-                    # a) missing file/typo/etc
-                    # b) using a module provided by the compiler, such as OpenMP
-                    # There's no easy way to tell which is which (that I know of)
-                    # so just ignore this and go on. Ideally we would print a
-                    # warning message to the user but this is a common occurrance,
-                    # which would lead to lots of distracting noise.
-                    continue
-                mod_source_file = tdeps[usename]
-                # Check if a source uses a module it exports itself.
-                # Potential bug if multiple targets have a file with
-                # the same name.
-                if mod_source_file.fname == os.path.split(src)[1]:
-                    continue
-                mod_name = compiler.module_name_to_filename(usematch.group(1))
-                mod_files.append(os.path.join(dirname, mod_name))
+        with open(src) as f:
+            for line in f:
+                usematch = usere.match(line)
+                if usematch is not None:
+                    usename = usematch.group(1)
+                    if usename not in tdeps:
+                        # The module is not provided by any source file. This
+                        # is due to:
+                        #   a) missing file/typo/etc
+                        #   b) using a module provided by the compiler, such as
+                        #      OpenMP
+                        # There's no easy way to tell which is which (that I
+                        # know of) so just ignore this and go on. Ideally we
+                        # would print a warning message to the user but this is
+                        # a common occurrence, which would lead to lots of
+                        # distracting noise.
+                        continue
+                    mod_source_file = tdeps[usename]
+                    # Check if a source uses a module it exports itself.
+                    # Potential bug if multiple targets have a file with
+                    # the same name.
+                    if mod_source_file.fname == os.path.split(src)[1]:
+                        continue
+                    mod_name = compiler.module_name_to_filename(
+                        usematch.group(1))
+                    mod_files.append(os.path.join(dirname, mod_name))
         return mod_files
 
     def get_cross_stdlib_args(self, target, compiler):
diff --git a/mesonbuild/backend/vs2010backend.py b/mesonbuild/backend/vs2010backend.py
index 669bcf890..eca747360 100644
--- a/mesonbuild/backend/vs2010backend.py
+++ b/mesonbuild/backend/vs2010backend.py
@@ -175,14 +175,18 @@ class Vs2010Backend(backends.Backend):
 
     @staticmethod
     def touch_regen_timestamp(build_dir):
-        open(Vs2010Backend.get_regen_stampfile(build_dir), 'w').close()
+        with open(Vs2010Backend.get_regen_stampfile(build_dir), 'w'):
+            pass
 
     def generate_regen_info(self):
         deps = self.get_regen_filelist()
         regeninfo = RegenInfo(self.environment.get_source_dir(),
                               self.environment.get_build_dir(),
                               deps)
-        pickle.dump(regeninfo, open(os.path.join(self.environment.get_scratch_dir(), 'regeninfo.dump'), 'wb'))
+        filename = os.path.join(self.environment.get_scratch_dir(),
+                                'regeninfo.dump')
+        with open(filename, 'wb') as f:
+            pickle.dump(regeninfo, f)
 
     def get_obj_target_deps(self, obj_list):
         result = {}
@@ -217,57 +221,66 @@ class Vs2010Backend(backends.Backend):
         return all_deps
 
     def generate_solution(self, sln_filename, projlist):
-        ofile = open(sln_filename, 'w')
-        ofile.write('Microsoft Visual Studio Solution File, Format Version 11.00\n')
-        ofile.write('# Visual Studio ' + self.vs_version + '\n')
-        prj_templ = prj_line = 'Project("{%s}") = "%s", "%s", "{%s}"\n'
-        for p in projlist:
-            prj_line = prj_templ % (self.environment.coredata.guid, p[0], p[1], p[2])
-            ofile.write(prj_line)
-            all_deps = self.determine_deps(p)
-            ofile.write('\tProjectSection(ProjectDependencies) = postProject\n')
-            regen_guid = self.environment.coredata.regen_guid
-            ofile.write('\t\t{%s} = {%s}\n' % (regen_guid, regen_guid))
-            for dep in all_deps.keys():
-                guid = self.environment.coredata.target_guids[dep]
-                ofile.write('\t\t{%s} = {%s}\n' % (guid, guid))
-            ofile.write('EndProjectSection\n')
+        with open(sln_filename, 'w') as ofile:
+            ofile.write('Microsoft Visual Studio Solution File, Format '
+                        'Version 11.00\n')
+            ofile.write('# Visual Studio ' + self.vs_version + '\n')
+            prj_templ = prj_line = 'Project("{%s}") = "%s", "%s", "{%s}"\n'
+            for p in projlist:
+                prj_line = prj_templ % (self.environment.coredata.guid,
+                                        p[0], p[1], p[2])
+                ofile.write(prj_line)
+                all_deps = self.determine_deps(p)
+                ofile.write('\tProjectSection(ProjectDependencies) = '
+                            'postProject\n')
+                regen_guid = self.environment.coredata.regen_guid
+                ofile.write('\t\t{%s} = {%s}\n' % (regen_guid, regen_guid))
+                for dep in all_deps.keys():
+                    guid = self.environment.coredata.target_guids[dep]
+                    ofile.write('\t\t{%s} = {%s}\n' % (guid, guid))
+                ofile.write('EndProjectSection\n')
+                ofile.write('EndProject\n')
+            test_line = prj_templ % (self.environment.coredata.guid,
+                                     'RUN_TESTS', 'RUN_TESTS.vcxproj',
+                                     self.environment.coredata.test_guid)
+            ofile.write(test_line)
             ofile.write('EndProject\n')
-        test_line = prj_templ % (self.environment.coredata.guid,
-                                 'RUN_TESTS', 'RUN_TESTS.vcxproj', self.environment.coredata.test_guid)
-        ofile.write(test_line)
-        ofile.write('EndProject\n')
-        regen_line = prj_templ % (self.environment.coredata.guid,
-                                 'REGEN', 'REGEN.vcxproj', self.environment.coredata.regen_guid)
-        ofile.write(regen_line)
-        ofile.write('EndProject\n')
-        ofile.write('Global\n')
-        ofile.write('\tGlobalSection(SolutionConfigurationPlatforms) = preSolution\n')
-        ofile.write('\t\t%s|%s = %s|%s\n' % (self.buildtype, self.platform, self.buildtype, self.platform))
-        ofile.write('\tEndGlobalSection\n')
-        ofile.write('\tGlobalSection(ProjectConfigurationPlatforms) = postSolution\n')
-        ofile.write('\t\t{%s}.%s|%s.ActiveCfg = %s|%s\n' % 
-                    (self.environment.coredata.regen_guid, self.buildtype, self.platform,
-                     self.buildtype, self.platform))
-        ofile.write('\t\t{%s}.%s|%s.Build.0 = %s|%s\n' % 
-                    (self.environment.coredata.regen_guid, self.buildtype, self.platform,
-                     self.buildtype, self.platform))
-        for p in projlist:
+            regen_line = prj_templ % (self.environment.coredata.guid,
+                                      'REGEN', 'REGEN.vcxproj',
+                                      self.environment.coredata.regen_guid)
+            ofile.write(regen_line)
+            ofile.write('EndProject\n')
+            ofile.write('Global\n')
+            ofile.write('\tGlobalSection(SolutionConfigurationPlatforms) = '
+                        'preSolution\n')
+            ofile.write('\t\t%s|%s = %s|%s\n' %
+                        (self.buildtype, self.platform, self.buildtype,
+                         self.platform))
+            ofile.write('\tEndGlobalSection\n')
+            ofile.write('\tGlobalSection(ProjectConfigurationPlatforms) = '
+                        'postSolution\n')
             ofile.write('\t\t{%s}.%s|%s.ActiveCfg = %s|%s\n' % 
-                        (p[2], self.buildtype, self.platform,
-                         self.buildtype, self.platform))
-            if not isinstance(self.build.targets[p[0]], build.RunTarget):
-                ofile.write('\t\t{%s}.%s|%s.Build.0 = %s|%s\n' %
+                        (self.environment.coredata.regen_guid, self.buildtype,
+                         self.platform, self.buildtype, self.platform))
+            ofile.write('\t\t{%s}.%s|%s.Build.0 = %s|%s\n' %
+                        (self.environment.coredata.regen_guid, self.buildtype,
+                         self.platform, self.buildtype, self.platform))
+            for p in projlist:
+                ofile.write('\t\t{%s}.%s|%s.ActiveCfg = %s|%s\n' %
                             (p[2], self.buildtype, self.platform,
                              self.buildtype, self.platform))
-        ofile.write('\t\t{%s}.%s|%s.ActiveCfg = %s|%s\n' % 
-                    (self.environment.coredata.test_guid, self.buildtype, self.platform,
-                     self.buildtype, self.platform))
-        ofile.write('\tEndGlobalSection\n')
-        ofile.write('\tGlobalSection(SolutionProperties) = preSolution\n')
-        ofile.write('\t\tHideSolutionNode = FALSE\n')
-        ofile.write('\tEndGlobalSection\n')
-        ofile.write('EndGlobal\n')
+                if not isinstance(self.build.targets[p[0]], build.RunTarget):
+                    ofile.write('\t\t{%s}.%s|%s.Build.0 = %s|%s\n' %
+                                (p[2], self.buildtype, self.platform,
+                                 self.buildtype, self.platform))
+            ofile.write('\t\t{%s}.%s|%s.ActiveCfg = %s|%s\n' %
+                        (self.environment.coredata.test_guid, self.buildtype,
+                         self.platform, self.buildtype, self.platform))
+            ofile.write('\tEndGlobalSection\n')
+            ofile.write('\tGlobalSection(SolutionProperties) = preSolution\n')
+            ofile.write('\t\tHideSolutionNode = FALSE\n')
+            ofile.write('\tEndGlobalSection\n')
+            ofile.write('EndGlobal\n')
 
     def generate_projects(self):
         projlist = []
@@ -862,12 +875,15 @@ class Vs2010Backend(backends.Backend):
         tree.write(ofname, encoding='utf-8', xml_declaration=True)
         # ElementTree can not do prettyprinting so do it manually
         doc = xml.dom.minidom.parse(ofname)
-        open(ofname, 'w').write(doc.toprettyxml())
+        with open(ofname, 'w') as of:
+            of.write(doc.toprettyxml())
         # World of horror! Python insists on not quoting quotes and
         # fixing the escaped &quot; into &amp;quot; whereas MSVS
         # requires quoted but not fixed elements. Enter horrible hack.
-        txt = open(ofname, 'r').read()
-        open(ofname, 'w').write(txt.replace('&amp;quot;', '&quot;'))
+        with open(ofname, 'r') as of:
+            txt = of.read()
+        with open(ofname, 'w') as of:
+            of.write(txt.replace('&amp;quot;', '&quot;'))
 
     def gen_regenproj(self, project_name, ofname):
         root = ET.Element('Project', {'DefaultTargets': 'Build',
diff --git a/mesonbuild/backend/xcodebackend.py b/mesonbuild/backend/xcodebackend.py
index e64866d08..b15774180 100644
--- a/mesonbuild/backend/xcodebackend.py
+++ b/mesonbuild/backend/xcodebackend.py
@@ -82,26 +82,22 @@ class XCodeBackend(backends.Backend):
         self.proj_dir = os.path.join(self.environment.get_build_dir(), self.build.project_name + '.xcodeproj')
         os.makedirs(self.proj_dir, exist_ok=True)
         self.proj_file = os.path.join(self.proj_dir, 'project.pbxproj')
-        self.ofile = open(self.proj_file, 'w')
-        self.generate_prefix()
-        self.generate_pbx_aggregate_target()
-        self.generate_pbx_build_file()
-        self.generate_pbx_build_style()
-        self.generate_pbx_container_item_proxy()
-        self.generate_pbx_file_reference()
-        self.generate_pbx_group()
-        self.generate_pbx_native_target()
-        self.generate_pbx_project()
-        self.generate_pbx_shell_build_phase(test_data)
-        self.generate_pbx_sources_build_phase()
-        self.generate_pbx_target_dependency()
-        self.generate_xc_build_configuration()
-        self.generate_xc_configurationList()
-        self.generate_suffix()
-
-        # for some reason, the entire file was not being flushed to the disk.
-        # closing it explicitly forces a flush and fixes the issue
-        self.ofile.close()
+        with open(self.proj_file, 'w') as self.ofile:
+            self.generate_prefix()
+            self.generate_pbx_aggregate_target()
+            self.generate_pbx_build_file()
+            self.generate_pbx_build_style()
+            self.generate_pbx_container_item_proxy()
+            self.generate_pbx_file_reference()
+            self.generate_pbx_group()
+            self.generate_pbx_native_target()
+            self.generate_pbx_project()
+            self.generate_pbx_shell_build_phase(test_data)
+            self.generate_pbx_sources_build_phase()
+            self.generate_pbx_target_dependency()
+            self.generate_xc_build_configuration()
+            self.generate_xc_configurationList()
+            self.generate_suffix()
 
     def get_xcodetype(self, fname):
         return self.xcodetypemap[fname.split('.')[-1]]
diff --git a/mesonbuild/compilers.py b/mesonbuild/compilers.py
index 1c6c1da7d..4088adc1c 100644
--- a/mesonbuild/compilers.py
+++ b/mesonbuild/compilers.py
@@ -538,9 +538,8 @@ class CCompiler(Compiler):
         binname += '.exe'
         # Write binary check source
         binary_name = os.path.join(work_dir, binname)
-        ofile = open(source_name, 'w')
-        ofile.write(code)
-        ofile.close()
+        with open(source_name, 'w') as ofile:
+            ofile.write(code)
         # Compile sanity check
         cmdlist = self.exelist + extra_flags + [source_name] + self.get_output_args(binary_name)
         pc = subprocess.Popen(cmdlist, stdout=subprocess.PIPE, stderr=subprocess.PIPE, cwd=work_dir)
@@ -617,9 +616,8 @@ int main () {{ {1}; }}'''
         suflen = len(self.default_suffix)
         (fd, srcname) = tempfile.mkstemp(suffix='.'+self.default_suffix)
         os.close(fd)
-        ofile = open(srcname, 'w')
-        ofile.write(code)
-        ofile.close()
+        with open(srcname, 'w') as ofile:
+            ofile.write(code)
         # Convert flags to the native type of the selected compiler
         args = self.unix_link_flags_to_native(extra_args)
         # Read c_args/cpp_args/etc from the cross-info file (if needed)
@@ -647,9 +645,8 @@ int main () {{ {1}; }}'''
         os.close(fd)
         (fd, dstname) = tempfile.mkstemp()
         os.close(fd)
-        ofile = open(srcname, 'w')
-        ofile.write(code)
-        ofile.close()
+        with open(srcname, 'w') as ofile:
+            ofile.write(code)
         # Convert flags to the native type of the selected compiler
         args = self.unix_link_flags_to_native(extra_args)
         # Select a CRT if needed since we're linking
@@ -672,9 +669,8 @@ int main () {{ {1}; }}'''
             raise CrossNoRunException('Can not run test applications in this cross environment.')
         (fd, srcname) = tempfile.mkstemp(suffix='.'+self.default_suffix)
         os.close(fd)
-        ofile = open(srcname, 'w')
-        ofile.write(code)
-        ofile.close()
+        with open(srcname, 'w') as ofile:
+            ofile.write(code)
         # Convert flags to the native type of the selected compiler
         args = self.unix_link_flags_to_native(extra_args)
         # Select a CRT if needed since we're linking
@@ -997,9 +993,9 @@ class ObjCCompiler(CCompiler):
         extra_flags = self.get_cross_extra_flags(environment, compile=True, link=False)
         if self.is_cross:
             extra_flags += self.get_compile_only_args()
-        ofile = open(source_name, 'w')
-        ofile.write('#import<stdio.h>\nint main(int argc, char **argv) { return 0; }\n')
-        ofile.close()
+        with open(source_name, 'w') as ofile:
+            ofile.write('#import<stdio.h>\n'
+                        'int main(int argc, char **argv) { return 0; }\n')
         pc = subprocess.Popen(self.exelist + extra_flags + [source_name, '-o', binary_name])
         pc.wait()
         if pc.returncode != 0:
@@ -1031,9 +1027,10 @@ class ObjCPPCompiler(CPPCompiler):
         extra_flags = self.get_cross_extra_flags(environment, compile=True, link=False)
         if self.is_cross:
             extra_flags += self.get_compile_only_args()
-        ofile = open(source_name, 'w')
-        ofile.write('#import<stdio.h>\nclass MyClass;int main(int argc, char **argv) { return 0; }\n')
-        ofile.close()
+        with open(source_name, 'w') as ofile:
+            ofile.write('#import<stdio.h>\n'
+                        'class MyClass;'
+                        'int main(int argc, char **argv) { return 0; }\n')
         pc = subprocess.Popen(self.exelist + extra_flags + [source_name, '-o', binary_name])
         pc.wait()
         if pc.returncode != 0:
@@ -1133,13 +1130,12 @@ class MonoCompiler(Compiler):
         src = 'sanity.cs'
         obj = 'sanity.exe'
         source_name = os.path.join(work_dir, src)
-        ofile = open(source_name, 'w')
-        ofile.write('''public class Sanity {
+        with open(source_name, 'w') as ofile:
+            ofile.write('''public class Sanity {
     static public void Main () {
     }
 }
 ''')
-        ofile.close()
         pc = subprocess.Popen(self.exelist + [src], cwd=work_dir)
         pc.wait()
         if pc.returncode != 0:
@@ -1245,14 +1241,13 @@ class JavaCompiler(Compiler):
         src = 'SanityCheck.java'
         obj = 'SanityCheck'
         source_name = os.path.join(work_dir, src)
-        ofile = open(source_name, 'w')
-        ofile.write('''class SanityCheck {
+        with open(source_name, 'w') as ofile:
+            ofile.write('''class SanityCheck {
   public static void main(String[] args) {
     int i;
   }
 }
 ''')
-        ofile.close()
         pc = subprocess.Popen(self.exelist + [src], cwd=work_dir)
         pc.wait()
         if pc.returncode != 0:
@@ -1292,11 +1287,10 @@ class ValaCompiler(Compiler):
     def sanity_check(self, work_dir, environment):
         src = 'valatest.vala'
         source_name = os.path.join(work_dir, src)
-        ofile = open(source_name, 'w')
-        ofile.write('''class SanityCheck : Object {
+        with open(source_name, 'w') as ofile:
+            ofile.write('''class SanityCheck : Object {
 }
 ''')
-        ofile.close()
         extra_flags = self.get_cross_extra_flags(environment, compile=True, link=False)
         pc = subprocess.Popen(self.exelist + extra_flags + ['-C', '-c', src], cwd=work_dir)
         pc.wait()
@@ -1336,11 +1330,10 @@ class RustCompiler(Compiler):
     def sanity_check(self, work_dir, environment):
         source_name = os.path.join(work_dir, 'sanity.rs')
         output_name = os.path.join(work_dir, 'rusttest')
-        ofile = open(source_name, 'w')
-        ofile.write('''fn main() {
+        with open(source_name, 'w') as ofile:
+            ofile.write('''fn main() {
 }
 ''')
-        ofile.close()
         pc = subprocess.Popen(self.exelist + ['-o', output_name, source_name], cwd=work_dir)
         pc.wait()
         if pc.returncode != 0:
@@ -1435,10 +1428,9 @@ class SwiftCompiler(Compiler):
         src = 'swifttest.swift'
         source_name = os.path.join(work_dir, src)
         output_name = os.path.join(work_dir, 'swifttest')
-        ofile = open(source_name, 'w')
-        ofile.write('''1 + 2
+        with open(source_name, 'w') as ofile:
+            ofile.write('''1 + 2
 ''')
-        ofile.close()
         extra_flags = self.get_cross_extra_flags(environment, compile=True, link=True)
         pc = subprocess.Popen(self.exelist + extra_flags + ['-emit-executable', '-o', output_name, src], cwd=work_dir)
         pc.wait()
@@ -1461,11 +1453,10 @@ class DCompiler(Compiler):
     def sanity_check(self, work_dir, environment):
         source_name = os.path.join(work_dir, 'sanity.d')
         output_name = os.path.join(work_dir, 'dtest')
-        ofile = open(source_name, 'w')
-        ofile.write('''void main() {
+        with open(source_name, 'w') as ofile:
+            ofile.write('''void main() {
 }
 ''')
-        ofile.close()
         pc = subprocess.Popen(self.exelist + self.get_output_args(output_name) + [source_name], cwd=work_dir)
         pc.wait()
         if pc.returncode != 0:
@@ -1872,9 +1863,8 @@ class VisualStudioCCompiler(CCompiler):
         code = 'int i;\n'
         (fd, srcname) = tempfile.mkstemp(suffix='.'+self.default_suffix)
         os.close(fd)
-        ofile = open(srcname, 'w')
-        ofile.write(code)
-        ofile.close()
+        with open(srcname, 'w') as ofile:
+            ofile.write(code)
         # Read c_args/cpp_args/etc from the cross-info file (if needed)
         extra_args = self.get_cross_extra_flags(env, compile=True, link=False)
         extra_args += self.get_compile_only_args()
@@ -2286,12 +2276,11 @@ class FortranCompiler(Compiler):
     def sanity_check(self, work_dir, environment):
         source_name = os.path.join(work_dir, 'sanitycheckf.f90')
         binary_name = os.path.join(work_dir, 'sanitycheckf')
-        ofile = open(source_name, 'w')
-        ofile.write('''program prog
+        with open(source_name, 'w') as ofile:
+            ofile.write('''program prog
      print *, "Fortran compilation is working."
 end program prog
 ''')
-        ofile.close()
         extra_flags = self.get_cross_extra_flags(environment, compile=True, link=True)
         pc = subprocess.Popen(self.exelist + extra_flags + [source_name, '-o', binary_name])
         pc.wait()
diff --git a/mesonbuild/coredata.py b/mesonbuild/coredata.py
index 2f1875f14..9beb2949f 100644
--- a/mesonbuild/coredata.py
+++ b/mesonbuild/coredata.py
@@ -154,7 +154,8 @@ class CoreData():
             raise RuntimeError('Tried to set unknown builtin option %s.' % optname)
 
 def load(filename):
-    obj = pickle.load(open(filename, 'rb'))
+    with open(filename, 'rb') as f:
+        obj = pickle.load(f)
     if not isinstance(obj, CoreData):
         raise RuntimeError('Core data file is corrupted.')
     if obj.version != version:
@@ -165,7 +166,8 @@ def load(filename):
 def save(obj, filename):
     if obj.version != version:
         raise RuntimeError('Fatal version mismatch corruption.')
-    pickle.dump(obj, open(filename, 'wb'))
+    with open(filename, 'wb') as f:
+        pickle.dump(obj, f)
 
 def get_builtin_options():
     return list(builtin_options.keys())
diff --git a/mesonbuild/dependencies.py b/mesonbuild/dependencies.py
index d123f77a6..679440df7 100644
--- a/mesonbuild/dependencies.py
+++ b/mesonbuild/dependencies.py
@@ -228,10 +228,11 @@ class PkgConfigDependency(Dependency):
         return self.is_found
 
     def extract_field(self, la_file, fieldname):
-        for line in open(la_file):
-            arr = line.strip().split('=')
-            if arr[0] == fieldname:
-                return arr[1][1:-1]
+        with open(la_file) as f:
+            for line in f:
+                arr = line.strip().split('=')
+                if arr[0] == fieldname:
+                    return arr[1][1:-1]
         return None
 
     def extract_dlname_field(self, la_file):
@@ -374,7 +375,8 @@ class ExternalProgram():
         shebang and manually parse it to figure out the interpreter to use
         """
         try:
-            first_line = open(script).readline().strip()
+            with open(script) as f:
+                first_line = f.readline().strip()
             if first_line.startswith('#!'):
                 commands = first_line[2:].split('#')[0].strip().split()
                 if mesonlib.is_windows():
@@ -552,12 +554,13 @@ class BoostDependency(Dependency):
         except FileNotFoundError:
             self.version = None
             return
-        for line in ifile:
-            if line.startswith("#define") and 'BOOST_LIB_VERSION' in line:
-                ver = line.split()[-1]
-                ver = ver[1:-1]
-                self.version = ver.replace('_', '.')
-                return
+        with ifile:
+            for line in ifile:
+                if line.startswith("#define") and 'BOOST_LIB_VERSION' in line:
+                    ver = line.split()[-1]
+                    ver = ver[1:-1]
+                    self.version = ver.replace('_', '.')
+                    return
         self.version = None
 
     def detect_src_modules(self):
diff --git a/mesonbuild/interpreter.py b/mesonbuild/interpreter.py
index 5e31a8763..ac95e15eb 100644
--- a/mesonbuild/interpreter.py
+++ b/mesonbuild/interpreter.py
@@ -1032,7 +1032,8 @@ class Interpreter():
         mesonfile = os.path.join(self.source_root, self.subdir, environment.build_filename)
         if not os.path.isfile(mesonfile):
             raise InvalidArguments('Missing Meson file in %s' % mesonfile)
-        code = open(mesonfile, encoding='utf8').read()
+        with open(mesonfile, encoding='utf8') as mf:
+           code = mf.read()
         if len(code.strip()) == 0:
             raise InvalidCode('Builder file is empty.')
         assert(isinstance(code, str))
@@ -2006,7 +2007,8 @@ class Interpreter():
         if not os.path.isfile(absname):
             self.subdir = prev_subdir
             raise InterpreterException('Nonexistant build def file %s.' % buildfilename)
-        code = open(absname, encoding='utf8').read()
+        with open(absname, encoding='utf8') as f:
+            code = f.read()
         assert(isinstance(code, str))
         try:
             codeblock = mparser.Parser(code).parse()
diff --git a/mesonbuild/mconf.py b/mesonbuild/mconf.py
index 4b11c1096..afabc6283 100644
--- a/mesonbuild/mconf.py
+++ b/mesonbuild/mconf.py
@@ -36,15 +36,18 @@ class Conf:
         self.build_file = os.path.join(build_dir, 'meson-private/build.dat')
         if not os.path.isfile(self.coredata_file) or not os.path.isfile(self.build_file):
             raise ConfException('Directory %s does not seem to be a Meson build directory.' % build_dir)
-        self.coredata = pickle.load(open(self.coredata_file, 'rb'))
-        self.build = pickle.load(open(self.build_file, 'rb'))
+        with open(self.coredata_file, 'rb') as f:
+            self.coredata = pickle.load(f)
+        with open(self.build_file, 'rb') as f:
+            self.build = pickle.load(f)
         if self.coredata.version != coredata.version:
             raise ConfException('Version mismatch (%s vs %s)' %
                                 (coredata.version, self.coredata.version))
 
     def save(self):
         # Only called if something has changed so overwrite unconditionally.
-        pickle.dump(self.coredata, open(self.coredata_file, 'wb'))
+        with open(self.coredata_file, 'wb') as f:
+            pickle.dump(self.coredata, f)
         # We don't write the build file because any changes to it
         # are erased when Meson is executed the nex time, i.e. the next
         # time Ninja is run.
diff --git a/mesonbuild/mesonlib.py b/mesonbuild/mesonlib.py
index b5b53397e..007aea833 100644
--- a/mesonbuild/mesonlib.py
+++ b/mesonbuild/mesonlib.py
@@ -96,7 +96,8 @@ def is_32bit():
 
 def is_debianlike():
     try:
-        open('/etc/debian_version', 'r')
+        with open('/etc/debian_version', 'r'):
+            pass
         return True
     except FileNotFoundError:
         return False
@@ -262,7 +263,8 @@ def do_mesondefine(line, confdata):
 
 def do_conf_file(src, dst, confdata):
     try:
-        data = open(src).readlines()
+        with open(src) as f:
+            data = f.readlines()
     except Exception:
         raise MesonException('Could not read input file %s.' % src)
     # Only allow (a-z, A-Z, 0-9, _, -) as valid characters for a define
@@ -276,7 +278,8 @@ def do_conf_file(src, dst, confdata):
             line = do_replacement(regex, line, confdata)
         result.append(line)
     dst_tmp = dst + '~'
-    open(dst_tmp, 'w').writelines(result)
+    with open(dst_tmp, 'w') as f:
+        f.writelines(result)
     shutil.copymode(src, dst_tmp)
     replace_if_different(dst, dst_tmp)
 
@@ -306,9 +309,10 @@ def replace_if_different(dst, dst_tmp):
     # If contents are identical, don't touch the file to prevent
     # unnecessary rebuilds.
     try:
-        if open(dst, 'r').read() == open(dst_tmp, 'r').read():
-            os.unlink(dst_tmp)
-            return
+        with open(dst, 'r') as f1, open(dst_tmp, 'r') as f2:
+            if f1.read() == f2.read():
+                os.unlink(dst_tmp)
+                return
     except FileNotFoundError:
         pass
     os.replace(dst_tmp, dst)
diff --git a/mesonbuild/mesonmain.py b/mesonbuild/mesonmain.py
index 8ed172019..f35d82182 100644
--- a/mesonbuild/mesonmain.py
+++ b/mesonbuild/mesonmain.py
@@ -169,7 +169,8 @@ itself as required.'''
         g.generate(intr)
         g.run_postconf_scripts()
         dumpfile = os.path.join(env.get_scratch_dir(), 'build.dat')
-        pickle.dump(b, open(dumpfile, 'wb'))
+        with open(dumpfile, 'wb') as f:
+            pickle.dump(b, f)
         # Write this last since we use the existence of this file to check if
         # we generated the build file successfully, so we don't want an error
         # that pops up during generation, post-conf scripts, etc to cause us to
diff --git a/mesonbuild/mintro.py b/mesonbuild/mintro.py
index 629b0fcd3..2086c3788 100644
--- a/mesonbuild/mintro.py
+++ b/mesonbuild/mintro.py
@@ -177,10 +177,14 @@ def run(args):
     buildfile = os.path.join(bdir, 'meson-private/build.dat')
     testfile = os.path.join(bdir, 'meson-private/meson_test_setup.dat')
     benchmarkfile = os.path.join(bdir, 'meson-private/meson_benchmark_setup.dat')
-    coredata = pickle.load(open(corefile, 'rb'))
-    builddata = pickle.load(open(buildfile, 'rb'))
-    testdata = pickle.load(open(testfile, 'rb'))
-    benchmarkdata = pickle.load(open(benchmarkfile, 'rb'))
+    with open(corefile, 'rb') as f:
+        coredata = pickle.load(f)
+    with open(buildfile, 'rb') as f:
+        builddata = pickle.load(f)
+    with open(testfile, 'rb') as f:
+       testdata = pickle.load(f)
+    with open(benchmarkfile, 'rb') as f:
+       benchmarkdata = pickle.load(f)
     if options.list_targets:
         list_targets(coredata, builddata)
     elif options.target_files is not None:
diff --git a/mesonbuild/modules/pkgconfig.py b/mesonbuild/modules/pkgconfig.py
index b01b58795..29e2847e1 100644
--- a/mesonbuild/modules/pkgconfig.py
+++ b/mesonbuild/modules/pkgconfig.py
@@ -23,37 +23,41 @@ class PkgConfigModule:
 
     def generate_pkgconfig_file(self, state, libraries, subdirs, name, description, version, filebase,
                                 pub_reqs, priv_reqs, priv_libs):
+        coredata = state.environment.get_coredata()
         outdir = state.environment.scratch_dir
         fname = os.path.join(outdir, filebase + '.pc')
-        ofile = open(fname, 'w')
-        coredata = state.environment.get_coredata()
-        ofile.write('prefix=%s\n' % coredata.get_builtin_option('prefix'))
-        ofile.write('libdir=${prefix}/%s\n' % coredata.get_builtin_option('libdir'))
-        ofile.write('includedir=${prefix}/%s\n\n' % coredata.get_builtin_option('includedir'))
-        ofile.write('Name: %s\n' % name)
-        if len(description) > 0:
-            ofile.write('Description: %s\n' % description)
-        if len(version) > 0:
-            ofile.write('Version: %s\n' % version)
-        if len(pub_reqs) > 0:
-            ofile.write('Requires: {}\n'.format(' '.join(pub_reqs)))
-        if len(priv_reqs) > 0:
-            ofile.write('Requires.private: {}\n'.format(' '.join(priv_reqs)))
-        if len(priv_libs) > 0:
-            ofile.write('Libraries.private: {}\n'.format(' '.join(priv_libs)))
-        ofile.write('Libs: -L${libdir} ')
-        for l in libraries:
-            if l.custom_install_dir:
-                ofile.write('-L${prefix}/%s ' % l.custom_install_dir)
-            ofile.write('-l%s ' % l.name)
-        ofile.write('\n')
-        ofile.write('CFlags: ')
-        for h in subdirs:
-            if h == '.':
-                h = ''
-            ofile.write(os.path.join('-I${includedir}', h))
-            ofile.write(' ')
-        ofile.write('\n')
+        with open(fname, 'w') as ofile:
+            ofile.write('prefix=%s\n' % coredata.get_builtin_option('prefix'))
+            ofile.write('libdir=${prefix}/%s\n' %
+                        coredata.get_builtin_option('libdir'))
+            ofile.write('includedir=${prefix}/%s\n\n' %
+                        coredata.get_builtin_option('includedir'))
+            ofile.write('Name: %s\n' % name)
+            if len(description) > 0:
+                ofile.write('Description: %s\n' % description)
+            if len(version) > 0:
+                ofile.write('Version: %s\n' % version)
+            if len(pub_reqs) > 0:
+                ofile.write('Requires: {}\n'.format(' '.join(pub_reqs)))
+            if len(priv_reqs) > 0:
+                ofile.write(
+                    'Requires.private: {}\n'.format(' '.join(priv_reqs)))
+            if len(priv_libs) > 0:
+                ofile.write(
+                    'Libraries.private: {}\n'.format(' '.join(priv_libs)))
+            ofile.write('Libs: -L${libdir} ')
+            for l in libraries:
+                if l.custom_install_dir:
+                    ofile.write('-L${prefix}/%s ' % l.custom_install_dir)
+                ofile.write('-l%s ' % l.name)
+            ofile.write('\n')
+            ofile.write('CFlags: ')
+            for h in subdirs:
+                if h == '.':
+                    h = ''
+                ofile.write(os.path.join('-I${includedir}', h))
+                ofile.write(' ')
+            ofile.write('\n')
 
     def generate(self, state, args, kwargs):
         if len(args) > 0:
diff --git a/mesonbuild/modules/rpm.py b/mesonbuild/modules/rpm.py
index acad204d2..89194e95f 100644
--- a/mesonbuild/modules/rpm.py
+++ b/mesonbuild/modules/rpm.py
@@ -80,82 +80,87 @@ class RPMModule:
                 files.add('%%{_mandir}/man%u/%s.*' % (int(man_file.split('.')[-1]), man_file))
         if len(files_devel) > 0:
             devel_subpkg = True
-        fn = open('%s.spec' % os.path.join(state.environment.get_build_dir(), proj), 'w+')
-        fn.write('Name: %s\n' % proj)
-        fn.write('Version: # FIXME\n')
-        fn.write('Release: 1%{?dist}\n')
-        fn.write('Summary: # FIXME\n')
-        fn.write('License: # FIXME\n')
-        fn.write('\n')
-        fn.write('Source0: %{name}-%{version}.tar.xz # FIXME\n')
-        fn.write('\n')
-        for compiler in compiler_deps:
-            fn.write('BuildRequires: %s\n' % compiler)
-        for dep in state.environment.coredata.deps:
-            fn.write('BuildRequires: pkgconfig(%s)\n' % dep)
-        for lib in state.environment.coredata.ext_libs.values():
-            fn.write('BuildRequires: %s # FIXME\n' % lib.fullpath)
-            mlog.log('Warning, replace', mlog.bold(lib.fullpath), 'with real package.',
-                     'You can use following command to find package which contains this lib:',
-                     mlog.bold('dnf provides %s' % lib.fullpath))
-        for prog in state.environment.coredata.ext_progs.values():
-            if not prog.found():
-                fn.write('BuildRequires: /usr/bin/%s # FIXME\n' % prog.get_name())
-            else:
-                fn.write('BuildRequires: %s\n' % ' '.join(prog.fullpath))
-        fn.write('BuildRequires: meson\n')
-        fn.write('\n')
-        fn.write('%description\n')
-        fn.write('\n')
-        if devel_subpkg:
-            fn.write('%package devel\n')
-            fn.write('Summary: Development files for %{name}\n')
-            fn.write('Requires: %{name}%{?_isa} = %{version}-%{release}\n')
+        filename = os.path.join(state.environment.get_build_dir(),
+                                '%s.spec' % proj)
+        with open(filename, 'w+') as fn:
+            fn.write('Name: %s\n' % proj)
+            fn.write('Version: # FIXME\n')
+            fn.write('Release: 1%{?dist}\n')
+            fn.write('Summary: # FIXME\n')
+            fn.write('License: # FIXME\n')
+            fn.write('\n')
+            fn.write('Source0: %{name}-%{version}.tar.xz # FIXME\n')
+            fn.write('\n')
+            for compiler in compiler_deps:
+                fn.write('BuildRequires: %s\n' % compiler)
+            for dep in state.environment.coredata.deps:
+                fn.write('BuildRequires: pkgconfig(%s)\n' % dep)
+            for lib in state.environment.coredata.ext_libs.values():
+                fn.write('BuildRequires: %s # FIXME\n' % lib.fullpath)
+                mlog.log('Warning, replace', mlog.bold(lib.fullpath),
+                         'with real package.',
+                         'You can use following command to find package which '
+                         'contains this lib:',
+                         mlog.bold('dnf provides %s' % lib.fullpath))
+            for prog in state.environment.coredata.ext_progs.values():
+                if not prog.found():
+                    fn.write('BuildRequires: /usr/bin/%s # FIXME\n' %
+                             prog.get_name())
+                else:
+                    fn.write('BuildRequires: %s\n' % ' '.join(prog.fullpath))
+            fn.write('BuildRequires: meson\n')
+            fn.write('\n')
+            fn.write('%description\n')
             fn.write('\n')
-            fn.write('%description devel\n')
-            fn.write('Development files for %{name}.\n')
+            if devel_subpkg:
+                fn.write('%package devel\n')
+                fn.write('Summary: Development files for %{name}\n')
+                fn.write('Requires: %{name}%{?_isa} = %{version}-%{release}\n')
+                fn.write('\n')
+                fn.write('%description devel\n')
+                fn.write('Development files for %{name}.\n')
+                fn.write('\n')
+            fn.write('%prep\n')
+            fn.write('%autosetup\n')
+            fn.write('rm -rf rpmbuilddir && mkdir rpmbuilddir\n')
             fn.write('\n')
-        fn.write('%prep\n')
-        fn.write('%autosetup\n')
-        fn.write('rm -rf rpmbuilddir && mkdir rpmbuilddir\n')
-        fn.write('\n')
-        fn.write('%build\n')
-        fn.write('pushd rpmbuilddir\n')
-        fn.write('  %meson ..\n')
-        fn.write('  ninja-build -v\n')
-        fn.write('popd\n')
-        fn.write('\n')
-        fn.write('%install\n')
-        fn.write('pushd rpmbuilddir\n')
-        fn.write('  DESTDIR=%{buildroot} ninja-build -v install\n')
-        fn.write('popd\n')
-        if len(to_delete) > 0:
-            fn.write('rm -rf %s\n' % ' '.join(to_delete))
-        fn.write('\n')
-        fn.write('%check\n')
-        fn.write('pushd rpmbuilddir\n')
-        fn.write('  ninja-build -v test\n')
-        fn.write('popd\n')
-        fn.write('\n')
-        fn.write('%files\n')
-        for f in files:
-            fn.write('%s\n' % f)
-        fn.write('\n')
-        if devel_subpkg:
-            fn.write('%files devel\n')
-            for f in files_devel:
+            fn.write('%build\n')
+            fn.write('pushd rpmbuilddir\n')
+            fn.write('  %meson ..\n')
+            fn.write('  ninja-build -v\n')
+            fn.write('popd\n')
+            fn.write('\n')
+            fn.write('%install\n')
+            fn.write('pushd rpmbuilddir\n')
+            fn.write('  DESTDIR=%{buildroot} ninja-build -v install\n')
+            fn.write('popd\n')
+            if len(to_delete) > 0:
+                fn.write('rm -rf %s\n' % ' '.join(to_delete))
+            fn.write('\n')
+            fn.write('%check\n')
+            fn.write('pushd rpmbuilddir\n')
+            fn.write('  ninja-build -v test\n')
+            fn.write('popd\n')
+            fn.write('\n')
+            fn.write('%files\n')
+            for f in files:
                 fn.write('%s\n' % f)
             fn.write('\n')
-        if so_installed:
-            fn.write('%post -p /sbin/ldconfig\n')
+            if devel_subpkg:
+                fn.write('%files devel\n')
+                for f in files_devel:
+                    fn.write('%s\n' % f)
+                fn.write('\n')
+            if so_installed:
+                fn.write('%post -p /sbin/ldconfig\n')
+                fn.write('\n')
+                fn.write('%postun -p /sbin/ldconfig\n')
+            fn.write('\n')
+            fn.write('%changelog\n')
+            fn.write('* %s meson <meson@example.com> - \n' %
+                     datetime.date.today().strftime('%a %b %d %Y'))
+            fn.write('- \n')
             fn.write('\n')
-            fn.write('%postun -p /sbin/ldconfig\n')
-        fn.write('\n')
-        fn.write('%changelog\n')
-        fn.write('* %s meson <meson@example.com> - \n' % datetime.date.today().strftime('%a %b %d %Y'))
-        fn.write('- \n')
-        fn.write('\n')
-        fn.close()
         mlog.log('RPM spec template written to %s.spec.\n' % proj)
 
 def initialize():
diff --git a/mesonbuild/optinterpreter.py b/mesonbuild/optinterpreter.py
index b35504747..9f57fd691 100644
--- a/mesonbuild/optinterpreter.py
+++ b/mesonbuild/optinterpreter.py
@@ -78,7 +78,8 @@ class OptionInterpreter:
 
     def process(self, option_file):
         try:
-            ast = mparser.Parser(open(option_file, 'r', encoding='utf8').read()).parse()
+            with open(option_file, 'r', encoding='utf8') as f:
+                ast = mparser.Parser(f.read()).parse()
         except mesonlib.MesonException as me:
             me.file = option_file
             raise me
diff --git a/mesonbuild/scripts/depfixer.py b/mesonbuild/scripts/depfixer.py
index cb136f460..7124c6f70 100644
--- a/mesonbuild/scripts/depfixer.py
+++ b/mesonbuild/scripts/depfixer.py
@@ -115,11 +115,21 @@ class Elf(DataSizes):
         self.bfile = bfile
         self.verbose = verbose
         self.bf = open(bfile, 'r+b')
-        (self.ptrsize, self.is_le) = self.detect_elf_type()
-        super().__init__(self.ptrsize, self.is_le)
-        self.parse_header()
-        self.parse_sections()
-        self.parse_dynamic()
+        try:
+            (self.ptrsize, self.is_le) = self.detect_elf_type()
+            super().__init__(self.ptrsize, self.is_le)
+            self.parse_header()
+            self.parse_sections()
+            self.parse_dynamic()
+        except:
+            self.bf.close()
+            raise
+
+    def __enter__(self):
+        return self
+
+    def __exit__(self, exc_type, exc_value, traceback):
+        self.bf.close()
 
     def detect_elf_type(self):
         data = self.bf.read(6)
@@ -308,13 +318,13 @@ def run(args):
         print('Don\'t run this unless you know what you are doing.')
         print('%s: <binary file> <prefix>' % sys.argv[0])
         exit(1)
-    e = Elf(args[0])
-    if len(args) == 1:
-        e.print_rpath()
-        e.print_runpath()
-    else:
-        new_rpath = args[1]
-        e.fix_rpath(new_rpath)
+    with Elf(args[0]) as e:
+        if len(args) == 1:
+            e.print_rpath()
+            e.print_runpath()
+        else:
+            new_rpath = args[1]
+            e.fix_rpath(new_rpath)
     return 0
 
 if __name__ == '__main__':
diff --git a/mesonbuild/scripts/meson_benchmark.py b/mesonbuild/scripts/meson_benchmark.py
index d1107b609..6d138b0db 100644
--- a/mesonbuild/scripts/meson_benchmark.py
+++ b/mesonbuild/scripts/meson_benchmark.py
@@ -52,33 +52,34 @@ def run_benchmarks(options, datafile):
     failed_tests = 0
     logfile_base = 'meson-logs/benchmarklog'
     jsonlogfilename = logfile_base+ '.json'
-    jsonlogfile = open(jsonlogfilename, 'w')
-    tests = pickle.load(open(datafile, 'rb'))
+    with open(datafile, 'rb') as f:
+        tests = pickle.load(f)
     num_tests = len(tests)
     if num_tests == 0:
         print('No benchmarks defined.')
         return 0
     iteration_count = 5
     wrap = [] # Benchmarks on cross builds are pointless so don't support them.
-    for i, test in enumerate(tests):
-        runs = []
-        durations = []
-        failed = False
-        for _ in range(iteration_count):
-            res = meson_test.run_single_test(wrap, test)
-            runs.append(res)
-            durations.append(res.duration)
-            if res.returncode != 0:
-                failed = True
-        mean = statistics.mean(durations)
-        stddev = statistics.stdev(durations)
-        if failed:
-            resultstr = 'FAIL'
-            failed_tests += 1
-        else:
-            resultstr = 'OK'
-        print_stats(3, num_tests, test.name, resultstr, i, mean, stddev)
-        print_json_log(jsonlogfile, runs, test.name, i)
+    with open(jsonlogfilename, 'w') as jsonlogfile:
+        for i, test in enumerate(tests):
+            runs = []
+            durations = []
+            failed = False
+            for _ in range(iteration_count):
+                res = meson_test.run_single_test(wrap, test)
+                runs.append(res)
+                durations.append(res.duration)
+                if res.returncode != 0:
+                    failed = True
+            mean = statistics.mean(durations)
+            stddev = statistics.stdev(durations)
+            if failed:
+                resultstr = 'FAIL'
+                failed_tests += 1
+            else:
+                resultstr = 'OK'
+            print_stats(3, num_tests, test.name, resultstr, i, mean, stddev)
+            print_json_log(jsonlogfile, runs, test.name, i)
     print('\nFull log written to meson-logs/benchmarklog.json.')
     return failed_tests
 
diff --git a/mesonbuild/scripts/meson_exe.py b/mesonbuild/scripts/meson_exe.py
index 1a0fcdaa8..d2ae35737 100644
--- a/mesonbuild/scripts/meson_exe.py
+++ b/mesonbuild/scripts/meson_exe.py
@@ -74,7 +74,8 @@ def run(args):
         print('Test runner for Meson. Do not run on your own, mmm\'kay?')
         print(sys.argv[0] + ' [data file]')
     exe_data_file = options.args[0]
-    exe = pickle.load(open(exe_data_file, 'rb'))
+    with open(exe_data_file, 'rb') as f:
+        exe = pickle.load(f)
     return run_exe(exe)
 
 if __name__ == '__main__':
diff --git a/mesonbuild/scripts/meson_install.py b/mesonbuild/scripts/meson_install.py
index 5c5e72c8f..5cf02e6e4 100644
--- a/mesonbuild/scripts/meson_install.py
+++ b/mesonbuild/scripts/meson_install.py
@@ -45,8 +45,8 @@ def get_destdir_path(d, path):
     return output
 
 def do_install(datafilename):
-    ifile = open(datafilename, 'rb')
-    d = pickle.load(ifile)
+    with open(datafilename, 'rb') as ifile:
+        d = pickle.load(ifile)
     d.destdir = os.environ.get('DESTDIR', '')
     d.fullprefix = destdir_join(d.destdir, d.prefix)
 
@@ -110,7 +110,9 @@ def install_man(d):
         os.makedirs(outdir, exist_ok=True)
         print('Installing %s to %s.' % (full_source_filename, outdir))
         if outfilename.endswith('.gz') and not full_source_filename.endswith('.gz'):
-            open(outfilename, 'wb').write(gzip.compress(open(full_source_filename, 'rb').read()))
+            with open(outfilename, 'wb') as of:
+                with open(full_source_filename, 'rb') as sf:
+                    of.write(gzip.compress(sf.read()))
             shutil.copystat(full_source_filename, outfilename)
             append_to_log(outfilename)
         else:
@@ -140,7 +142,8 @@ def run_install_script(d):
         print('Running custom install script %s' % script)
         suffix = os.path.splitext(script)[1].lower()
         if platform.system().lower() == 'windows' and suffix != '.bat':
-            first_line = open(script, encoding='latin_1', errors='ignore').readline().strip()
+            with open(script, encoding='latin_1', errors='ignore') as f:
+                first_line = f.readline().strip()
             if first_line.startswith('#!'):
                 if shutil.which(first_line[2:]):
                     commands = [first_line[2:]]
diff --git a/mesonbuild/scripts/meson_test.py b/mesonbuild/scripts/meson_test.py
index 33b616526..951fb851f 100644
--- a/mesonbuild/scripts/meson_test.py
+++ b/mesonbuild/scripts/meson_test.py
@@ -202,10 +202,8 @@ def run_tests(datafilename):
         wrap = [options.wrapper]
         logfilename = logfile_base + '-' + options.wrapper.replace(' ', '_') + '.txt'
         jsonlogfilename = logfile_base + '-' + options.wrapper.replace(' ', '_') + '.json'
-    logfile = open(logfilename, 'w')
-    jsonlogfile = open(jsonlogfilename, 'w')
-    logfile.write('Log of Meson test suite run on %s.\n\n' % datetime.datetime.now().isoformat())
-    tests = pickle.load(open(datafilename, 'rb'))
+    with open(datafilename, 'rb') as f:
+        tests = pickle.load(f)
     if len(tests) == 0:
         print('No tests defined.')
         return
@@ -222,24 +220,31 @@ def run_tests(datafilename):
     executor = conc.ThreadPoolExecutor(max_workers=num_workers)
     futures = []
     filtered_tests = filter_tests(options.suite, tests)
-    for i, test in enumerate(filtered_tests):
-        if test.suite[0] == '':
-            visible_name = test.name
-        else:
-            if options.suite is not None:
-                visible_name = options.suite + ' / ' + test.name
+
+    with open(jsonlogfilename, 'w') as jsonlogfile, \
+         open(logfilename, 'w') as logfile:
+        logfile.write('Log of Meson test suite run on %s.\n\n' %
+                      datetime.datetime.now().isoformat())
+        for i, test in enumerate(filtered_tests):
+            if test.suite[0] == '':
+                visible_name = test.name
             else:
-                visible_name = test.suite[0] + ' / ' + test.name
+                if options.suite is not None:
+                    visible_name = options.suite + ' / ' + test.name
+                else:
+                    visible_name = test.suite[0] + ' / ' + test.name
 
-        if not test.is_parallel:
-            drain_futures(futures)
-            futures = []
-            res = run_single_test(wrap, test)
-            print_stats(numlen, filtered_tests, visible_name, res, i, logfile, jsonlogfile)
-        else:
-            f = executor.submit(run_single_test, wrap, test)
-            futures.append((f, numlen, filtered_tests, visible_name, i, logfile, jsonlogfile))
-    drain_futures(futures)
+            if not test.is_parallel:
+                drain_futures(futures)
+                futures = []
+                res = run_single_test(wrap, test)
+                print_stats(numlen, filtered_tests, visible_name, res, i,
+                            logfile, jsonlogfile)
+            else:
+                f = executor.submit(run_single_test, wrap, test)
+                futures.append((f, numlen, filtered_tests, visible_name, i,
+                                logfile, jsonlogfile))
+        drain_futures(futures)
     return logfilename
 
 def run(args):
diff --git a/mesonbuild/scripts/regen_checker.py b/mesonbuild/scripts/regen_checker.py
index f65f3bdab..ddf494332 100644
--- a/mesonbuild/scripts/regen_checker.py
+++ b/mesonbuild/scripts/regen_checker.py
@@ -48,8 +48,10 @@ def run(args):
     private_dir = args[0]
     dumpfile = os.path.join(private_dir, 'regeninfo.dump')
     coredata = os.path.join(private_dir, 'coredata.dat')
-    regeninfo = pickle.load(open(dumpfile, 'rb'))
-    coredata = pickle.load(open(coredata, 'rb'))
+    with open(dumpfile, 'rb') as f:
+        regeninfo = pickle.load(f)
+    with open(coredata, 'rb') as f:
+        coredata = pickle.load(f)
     mesonscript = coredata.meson_script_file
     backend = coredata.get_builtin_option('backend')
     regen_timestamp = os.stat(dumpfile).st_mtime
diff --git a/mesonbuild/scripts/symbolextractor.py b/mesonbuild/scripts/symbolextractor.py
index 79c126420..c117301d4 100644
--- a/mesonbuild/scripts/symbolextractor.py
+++ b/mesonbuild/scripts/symbolextractor.py
@@ -34,16 +34,19 @@ parser.add_argument('args', nargs='+')
 
 def dummy_syms(outfilename):
     """Just touch it so relinking happens always."""
-    open(outfilename, 'w').close()
+    with open(outfilename, 'w'):
+        pass
 
 def write_if_changed(text, outfilename):
     try:
-        oldtext = open(outfilename, 'r').read()
+        with open(outfilename, 'r') as f:
+            oldtext = f.read()
         if text == oldtext:
             return
     except FileNotFoundError:
         pass
-    open(outfilename, 'w').write(text)
+    with open(outfilename, 'w') as f:
+        f.write(text)
 
 def linux_syms(libfilename, outfilename):
     pe = subprocess.Popen(['readelf', '-d', libfilename], stdout=subprocess.PIPE, stderr=subprocess.PIPE)
diff --git a/mesonbuild/scripts/vcstagger.py b/mesonbuild/scripts/vcstagger.py
index 390e37a8d..3f36e0af4 100644
--- a/mesonbuild/scripts/vcstagger.py
+++ b/mesonbuild/scripts/vcstagger.py
@@ -23,9 +23,16 @@ def config_vcs_tag(infile, outfile, fallback, source_dir, replace_string, regex_
     except Exception:
         new_string = fallback
 
-    new_data = open(infile).read().replace(replace_string, new_string)
-    if (not os.path.exists(outfile)) or (open(outfile).read() != new_data):
-        open(outfile, 'w').write(new_data)
+    with open(infile) as f:
+        new_data = f.read().replace(replace_string, new_string)
+    if os.path.exists(outfile):
+        with open(outfile) as f:
+            needs_update = (f.read() != new_data)
+    else:
+        needs_update = True
+    if needs_update:
+        with open(outfile, 'w') as f:
+            f.write(new_data)
 
 def run(args):
     infile, outfile, fallback, source_dir, replace_string, regex_selector = args[0:6]
diff --git a/mesonbuild/wrap/wrap.py b/mesonbuild/wrap/wrap.py
index bfb7ed473..f03af6704 100644
--- a/mesonbuild/wrap/wrap.py
+++ b/mesonbuild/wrap/wrap.py
@@ -13,6 +13,7 @@
 # limitations under the License.
 
 from .. import mlog
+import contextlib
 import urllib.request, os, hashlib, shutil
 import subprocess
 import sys
@@ -58,23 +59,23 @@ def open_wrapdburl(urlstring):
 class PackageDefinition:
     def __init__(self, fname):
         self.values = {}
-        ifile = open(fname)
-        first = ifile.readline().strip()
+        with open(fname) as ifile:
+            first = ifile.readline().strip()
 
-        if first == '[wrap-file]':
-            self.type = 'file'
-        elif first == '[wrap-git]':
-            self.type = 'git'
-        else:
-            raise RuntimeError('Invalid format of package file')
-        for line in ifile:
-            line = line.strip()
-            if line == '':
-                continue
-            (k, v) = line.split('=', 1)
-            k = k.strip()
-            v = v.strip()
-            self.values[k] = v
+            if first == '[wrap-file]':
+                self.type = 'file'
+            elif first == '[wrap-git]':
+                self.type = 'git'
+            else:
+                raise RuntimeError('Invalid format of package file')
+            for line in ifile:
+                line = line.strip()
+                if line == '':
+                    continue
+                (k, v) = line.split('=', 1)
+                k = k.strip()
+                v = v.strip()
+                self.values[k] = v
 
     def get(self, key):
         return self.values[key]
@@ -137,26 +138,26 @@ class Resolver:
             resp = open_wrapdburl(url)
         else:
             resp = urllib.request.urlopen(url)
-        dlsize = int(resp.info()['Content-Length'])
-        print('Download size:', dlsize)
-        print('Downloading: ', end='')
-        sys.stdout.flush()
-        printed_dots = 0
-        blocks = []
-        downloaded = 0
-        while True:
-            block = resp.read(blocksize)
-            if block == b'':
-                break
-            downloaded += len(block)
-            blocks.append(block)
-            ratio = int(downloaded/dlsize * 10)
-            while printed_dots < ratio:
-                print('.', end='')
-                sys.stdout.flush()
-                printed_dots += 1
-        print('')
-        resp.close()
+        with contextlib.closing(resp) as resp:
+            dlsize = int(resp.info()['Content-Length'])
+            print('Download size:', dlsize)
+            print('Downloading: ', end='')
+            sys.stdout.flush()
+            printed_dots = 0
+            blocks = []
+            downloaded = 0
+            while True:
+                block = resp.read(blocksize)
+                if block == b'':
+                    break
+                downloaded += len(block)
+                blocks.append(block)
+                ratio = int(downloaded/dlsize * 10)
+                while printed_dots < ratio:
+                    print('.', end='')
+                    sys.stdout.flush()
+                    printed_dots += 1
+            print('')
         return b''.join(blocks)
 
     def get_hash(self, data):
@@ -177,7 +178,8 @@ class Resolver:
         expected = p.get('source_hash')
         if dhash != expected:
             raise RuntimeError('Incorrect hash for source %s:\n %s expected\n %s actual.' % (packagename, expected, dhash))
-        open(ofname, 'wb').write(srcdata)
+        with open(ofname, 'wb') as f:
+            f.write(srcdata)
         if p.has_patch():
             purl = p.get('patch_url')
             mlog.log('Downloading patch from', mlog.bold(purl))
@@ -186,7 +188,9 @@ class Resolver:
             expected = p.get('patch_hash')
             if phash != expected:
                 raise RuntimeError('Incorrect hash for patch %s:\n %s expected\n %s actual' % (packagename, expected, phash))
-            open(os.path.join(self.cachedir, p.get('patch_filename')), 'wb').write(pdata)
+            filename = os.path.join(self.cachedir, p.get('patch_filename'))
+            with open(filename, 'wb') as f:
+                f.write(pdata)
         else:
             mlog.log('Package does not require patch.')
 
diff --git a/mesonbuild/wrap/wraptool.py b/mesonbuild/wrap/wraptool.py
index c5f8eeffe..e94a2c5a6 100755
--- a/mesonbuild/wrap/wraptool.py
+++ b/mesonbuild/wrap/wraptool.py
@@ -92,7 +92,8 @@ def install(name):
     (branch, revision) = get_latest_version(name)
     u = open_wrapdburl(API_ROOT + 'projects/%s/%s/%s/get_wrap' % (name, branch, revision))
     data = u.read()
-    open(wrapfile, 'wb').write(data)
+    with open(wrapfile, 'wb') as f:
+        f.write(data)
     print('Installed', name, 'branch', branch, 'revision', revision)
 
 def get_current_version(wrapfile):
@@ -129,7 +130,8 @@ def update(name):
         os.unlink(os.path.join('subprojects/packagecache', patch_file))
     except FileNotFoundError:
         pass
-    open(wrapfile, 'wb').write(data)
+    with open(wrapfile, 'wb') as f:
+        f.write(data)
     print('Updated', name, 'to branch', new_branch, 'revision', new_revision)
 
 def info(name):
diff --git a/run_tests.py b/run_tests.py
index 3e4966229..48f123026 100755
--- a/run_tests.py
+++ b/run_tests.py
@@ -156,8 +156,9 @@ def validate_install(srcdir, installdir):
     if os.path.exists(os.path.join(installdir, noinst_file)):
         expected[noinst_file] = False
     elif os.path.exists(info_file):
-        for line in open(info_file):
-            expected[platform_fix_exe_name(line.strip())] = False
+        with open(info_file) as f:
+            for line in f:
+                expected[platform_fix_exe_name(line.strip())] = False
     # Check if expected files were found
     for fname in expected:
         if os.path.exists(os.path.join(installdir, fname)):
@@ -249,7 +250,8 @@ def _run_test(testdir, test_build_dir, install_dir, extra_args, flags, compile_c
     (returncode, stdo, stde) = run_configure_inprocess(gen_command)
     try:
         logfile = os.path.join(test_build_dir, 'meson-logs/meson-log.txt')
-        mesonlog = open(logfile, errors='ignore').read()
+        with open(logfile, errors='ignore') as f:
+            mesonlog = f.read()
     except Exception:
         mesonlog = 'No meson-log.txt found.'
     gen_time = time.time() - gen_start
@@ -401,7 +403,9 @@ def run_tests(extra_args):
 
 def check_file(fname):
     linenum = 1
-    for line in open(fname, 'rb').readlines():
+    with open(fname, 'rb') as f:
+        lines = f.readlines()
+    for line in lines:
         if b'\t' in line:
             print("File %s contains a literal tab on line %d. Only spaces are permitted." % (fname, linenum))
             sys.exit(1)
diff --git a/test cases/common/103 manygen/subdir/manygen.py b/test cases/common/103 manygen/subdir/manygen.py
index 441118363..c233ae6bc 100755
--- a/test cases/common/103 manygen/subdir/manygen.py	
+++ b/test cases/common/103 manygen/subdir/manygen.py	
@@ -6,7 +6,8 @@
 import sys, os
 import shutil, subprocess
 
-funcname = open(sys.argv[1]).readline().strip()
+with open(sys.argv[1]) as f:
+    funcname = f.readline().strip()
 outdir = sys.argv[2]
 
 if not os.path.isdir(outdir):
@@ -44,19 +45,22 @@ outc = os.path.join(outdir, funcname + '.c')
 tmpc = 'diibadaaba.c'
 tmpo = 'diibadaaba' + objsuffix
 
-open(outc, 'w').write('''#include"%s.h"
+with open(outc, 'w') as f:
+    f.write('''#include"%s.h"
 int %s_in_src() {
   return 0;
 }
 ''' % (funcname, funcname))
 
-open(outh, 'w').write('''#pragma once
+with open(outh, 'w') as f:
+    f.write('''#pragma once
 int %s_in_lib();
 int %s_in_obj();
 int %s_in_src();
 ''' % (funcname, funcname, funcname))
 
-open(tmpc, 'w').write('''int %s_in_obj() {
+with open(tmpc, 'w') as f:
+    f.write('''int %s_in_obj() {
   return 0;
 }
 ''' % funcname)
@@ -66,7 +70,8 @@ if is_vs:
 else:
     subprocess.check_call([compiler, '-c', '-o', outo, tmpc])
 
-open(tmpc, 'w').write('''int %s_in_lib() {
+with open(tmpc, 'w') as f:
+    f.write('''int %s_in_lib() {
   return 0;
 }
 ''' % funcname)
diff --git a/test cases/common/107 postconf/postconf.py b/test cases/common/107 postconf/postconf.py
index 209b7af22..50c91ca24 100644
--- a/test cases/common/107 postconf/postconf.py	
+++ b/test cases/common/107 postconf/postconf.py	
@@ -7,5 +7,10 @@ template = '''#pragma once
 #define THE_NUMBER {}
 '''
 
-data = open(os.path.join(os.environ['MESON_SOURCE_ROOT'], 'raw.dat')).readline().strip()
-open(os.path.join(os.environ['MESON_BUILD_ROOT'], 'generated.h'), 'w').write(template.format(data))
+input_file = os.path.join(os.environ['MESON_SOURCE_ROOT'], 'raw.dat')
+output_file = os.path.join(os.environ['MESON_BUILD_ROOT'], 'generated.h')
+
+with open(input_file) as f:
+    data = f.readline().strip()
+with open(output_file, 'w') as f:
+    f.write(template.format(data))
diff --git a/test cases/common/108 postconf with args/postconf.py b/test cases/common/108 postconf with args/postconf.py
index 4cfbb7ce0..cef7f790f 100644
--- a/test cases/common/108 postconf with args/postconf.py	
+++ b/test cases/common/108 postconf with args/postconf.py	
@@ -9,5 +9,10 @@ template = '''#pragma once
 #define THE_ARG2 {}
 '''
 
-data = open(os.path.join(os.environ['MESON_SOURCE_ROOT'], 'raw.dat')).readline().strip()
-open(os.path.join(os.environ['MESON_BUILD_ROOT'], 'generated.h'), 'w').write(template.format(data, sys.argv[1], sys.argv[2]))
+input_file = os.path.join(os.environ['MESON_SOURCE_ROOT'], 'raw.dat')
+output_file = os.path.join(os.environ['MESON_BUILD_ROOT'], 'generated.h')
+
+with open(input_file) as f:
+    data = f.readline().strip()
+with open(output_file, 'w') as f:
+    f.write(template.format(data, sys.argv[1], sys.argv[2]))
diff --git a/test cases/common/113 generatorcustom/catter.py b/test cases/common/113 generatorcustom/catter.py
index 354d6e080..7a6c085df 100755
--- a/test cases/common/113 generatorcustom/catter.py	
+++ b/test cases/common/113 generatorcustom/catter.py	
@@ -8,6 +8,7 @@ inputs = sys.argv[1:-1]
 with open(output, 'w') as ofile:
     ofile.write('#pragma once\n')
     for i in inputs:
-        content = open(i, 'r').read()
+        with open(i, 'r') as ifile:
+            content = ifile.read()
         ofile.write(content)
         ofile.write('\n')
diff --git a/test cases/common/113 generatorcustom/gen.py b/test cases/common/113 generatorcustom/gen.py
index ba02e3fbc..c8434974b 100755
--- a/test cases/common/113 generatorcustom/gen.py	
+++ b/test cases/common/113 generatorcustom/gen.py	
@@ -5,7 +5,9 @@ import sys, os
 ifile = sys.argv[1]
 ofile = sys.argv[2]
 
-resname = open(ifile, 'r').readline().strip()
+with open(ifile, 'r') as f:
+    resname = f.readline().strip()
 
 templ = 'const char %s[] = "%s";\n'
-open(ofile, 'w').write(templ % (resname, resname))
+with open(ofile, 'w') as f:
+    f.write(templ % (resname, resname))
diff --git a/test cases/common/117 custom target capture/my_compiler.py b/test cases/common/117 custom target capture/my_compiler.py
index 3e9ec23cc..b60722a5e 100755
--- a/test cases/common/117 custom target capture/my_compiler.py	
+++ b/test cases/common/117 custom target capture/my_compiler.py	
@@ -6,7 +6,8 @@ if __name__ == '__main__':
     if len(sys.argv) != 2:
         print(sys.argv[0], 'input_file')
         sys.exit(1)
-    ifile = open(sys.argv[1]).read()
+    with open(sys.argv[1]) as f:
+        ifile = f.read()
     if ifile != 'This is a text only input file.\n':
         print('Malformed input')
         sys.exit(1)
diff --git a/test cases/common/16 configure file/generator.py b/test cases/common/16 configure file/generator.py
index de9a423ab..90223f07f 100755
--- a/test cases/common/16 configure file/generator.py	
+++ b/test cases/common/16 configure file/generator.py	
@@ -6,8 +6,8 @@ if len(sys.argv) != 3:
     print("Wrong amount of parameters.")
 
 # Just test that it exists.
-ifile = open(sys.argv[1], 'r')
+with open(sys.argv[1], 'r') as ifile:
+    pass
 
-ofile = open(sys.argv[2], 'w')
-ofile.write("#define ZERO_RESULT 0\n")
-ofile.close()
+with open(sys.argv[2], 'w') as ofile:
+    ofile.write("#define ZERO_RESULT 0\n")
diff --git a/test cases/common/48 test args/tester.py b/test cases/common/48 test args/tester.py
index 36e510d72..0b4010ab9 100755
--- a/test cases/common/48 test args/tester.py	
+++ b/test cases/common/48 test args/tester.py	
@@ -2,5 +2,6 @@
 
 import sys
 
-if open(sys.argv[1]).read() != 'contents\n':
-  sys.exit(1)
+with open(sys.argv[1]) as f:
+    if f.read() != 'contents\n':
+        sys.exit(1)
diff --git a/test cases/common/56 custom target/depfile/dep.py b/test cases/common/56 custom target/depfile/dep.py
index 3a772ec84..585e1927c 100755
--- a/test cases/common/56 custom target/depfile/dep.py	
+++ b/test cases/common/56 custom target/depfile/dep.py	
@@ -9,5 +9,7 @@ depfiles = glob(os.path.join(srcdir, '*'))
 
 quoted_depfiles = [x.replace(' ', '\ ') for x in depfiles]
 
-open(output, 'w').write('I am the result of globbing.')
-open(depfile, 'w').write('%s: %s\n' % (output, ' '.join(quoted_depfiles)))
+with open(output, 'w') as f:
+    f.write('I am the result of globbing.')
+with open(depfile, 'w') as f:
+    f.write('%s: %s\n' % (output, ' '.join(quoted_depfiles)))
diff --git a/test cases/common/56 custom target/my_compiler.py b/test cases/common/56 custom target/my_compiler.py
index 43e714350..d99029bcc 100755
--- a/test cases/common/56 custom target/my_compiler.py	
+++ b/test cases/common/56 custom target/my_compiler.py	
@@ -6,9 +6,10 @@ if __name__ == '__main__':
     if len(sys.argv) != 3:
         print(sys.argv[0], 'input_file output_file')
         sys.exit(1)
-    ifile = open(sys.argv[1]).read()
+    with open(sys.argv[1]) as f:
+        ifile = f.read()
     if ifile != 'This is a text only input file.\n':
         print('Malformed input')
         sys.exit(1)
-    ofile = open(sys.argv[2], 'w')
-    ofile.write('This is a binary output file.\n')
+    with open(sys.argv[2], 'w') as ofile:
+        ofile.write('This is a binary output file.\n')
diff --git a/test cases/common/57 custom target chain/my_compiler.py b/test cases/common/57 custom target chain/my_compiler.py
index 43e714350..d99029bcc 100755
--- a/test cases/common/57 custom target chain/my_compiler.py	
+++ b/test cases/common/57 custom target chain/my_compiler.py	
@@ -6,9 +6,10 @@ if __name__ == '__main__':
     if len(sys.argv) != 3:
         print(sys.argv[0], 'input_file output_file')
         sys.exit(1)
-    ifile = open(sys.argv[1]).read()
+    with open(sys.argv[1]) as f:
+        ifile = f.read()
     if ifile != 'This is a text only input file.\n':
         print('Malformed input')
         sys.exit(1)
-    ofile = open(sys.argv[2], 'w')
-    ofile.write('This is a binary output file.\n')
+    with open(sys.argv[2], 'w') as ofile:
+        ofile.write('This is a binary output file.\n')
diff --git a/test cases/common/57 custom target chain/my_compiler2.py b/test cases/common/57 custom target chain/my_compiler2.py
index 22a416015..22ec7897b 100755
--- a/test cases/common/57 custom target chain/my_compiler2.py	
+++ b/test cases/common/57 custom target chain/my_compiler2.py	
@@ -6,9 +6,10 @@ if __name__ == '__main__':
     if len(sys.argv) != 3:
         print(sys.argv[0], 'input_file output_file')
         sys.exit(1)
-    ifile = open(sys.argv[1]).read()
+    with open(sys.argv[1]) as f:
+        ifile = f.read()
     if ifile != 'This is a binary output file.\n':
         print('Malformed input')
         sys.exit(1)
-    ofile = open(sys.argv[2], 'w')
-    ofile.write('This is a different binary output file.\n')
+    with open(sys.argv[2], 'w') as ofile:
+        ofile.write('This is a different binary output file.\n')
diff --git a/test cases/common/57 custom target chain/usetarget/subcomp.py b/test cases/common/57 custom target chain/usetarget/subcomp.py
index 207a8ad97..6f4b68603 100755
--- a/test cases/common/57 custom target chain/usetarget/subcomp.py	
+++ b/test cases/common/57 custom target chain/usetarget/subcomp.py	
@@ -3,5 +3,5 @@
 import sys, os
 
 with open(sys.argv[1], 'rb') as ifile:
-    open(sys.argv[2], 'w').write('Everything ok.\n')
-
+    with open(sys.argv[2], 'w') as ofile:
+        ofile.write('Everything ok.\n')
diff --git a/test cases/common/58 run target/converter.py b/test cases/common/58 run target/converter.py
index 6acbc84e1..8dd31fe2f 100644
--- a/test cases/common/58 run target/converter.py	
+++ b/test cases/common/58 run target/converter.py	
@@ -2,4 +2,5 @@
 
 import sys
 
-open(sys.argv[2], 'wb').write(open(sys.argv[1], 'rb').read())
+with open(sys.argv[1], 'rb') as ifile, open(sys.argv[2], 'wb') as ofile:
+    ofile.write(ifile.read())
diff --git a/test cases/common/58 run target/fakeburner.py b/test cases/common/58 run target/fakeburner.py
index a100a6f66..57280024a 100755
--- a/test cases/common/58 run target/fakeburner.py	
+++ b/test cases/common/58 run target/fakeburner.py	
@@ -5,7 +5,8 @@ import sys
 plain_arg = sys.argv[1]
 _, filename, _ = plain_arg.split(':')
 try:
-    content = open(filename, 'rb').read()
+    with open(filename, 'rb') as f:
+        content = f.read()
 except FileNotFoundError:
     print('Could not open file. Missing dependency?')
     sys.exit(1)
diff --git a/test cases/common/61 custom target source output/generator.py b/test cases/common/61 custom target source output/generator.py
index 4bf5c8432..3464b0a85 100755
--- a/test cases/common/61 custom target source output/generator.py	
+++ b/test cases/common/61 custom target source output/generator.py	
@@ -7,8 +7,10 @@ if len(sys.argv) != 2:
 
 odir = sys.argv[1]
 
-open(os.path.join(odir, 'mylib.h'), 'w').write('int func();\n')
-open(os.path.join(odir, 'mylib.c'), 'w').write('''int func() {
+with open(os.path.join(odir, 'mylib.h'), 'w') as f:
+    f.write('int func();\n')
+with open(os.path.join(odir, 'mylib.c'), 'w') as f:
+    f.write('''int func() {
     return 0;
 }
 ''')
diff --git a/test cases/common/64 custom header generator/makeheader.py b/test cases/common/64 custom header generator/makeheader.py
index 9ef2bd5f0..f15683447 100644
--- a/test cases/common/64 custom header generator/makeheader.py	
+++ b/test cases/common/64 custom header generator/makeheader.py	
@@ -6,5 +6,7 @@
 import sys
 
 template = '#define RET_VAL %s\n'
-output = template % (open(sys.argv[1]).readline().strip())
-open(sys.argv[2], 'w').write(output)
+with open(sys.argv[1]) as f:
+    output = template % (f.readline().strip(), )
+with open(sys.argv[2], 'w') as f:
+    f.write(output)
diff --git a/test cases/common/65 multiple generators/mygen.py b/test cases/common/65 multiple generators/mygen.py
index cd786ead1..99dc33136 100755
--- a/test cases/common/65 multiple generators/mygen.py	
+++ b/test cases/common/65 multiple generators/mygen.py	
@@ -6,14 +6,17 @@ if len(sys.argv) != 3:
     print("You is fail.")
     sys.exit(1)
 
-val = open(sys.argv[1]).read().strip()
+with open(sys.argv[1]) as f:
+    val = f.read().strip()
 outdir = sys.argv[2]
 
 outhdr = os.path.join(outdir, 'source%s.h' % val)
 outsrc = os.path.join(outdir, 'source%s.cpp' % val)
 
-open(outhdr, 'w').write('int func%s();\n' % val)
-open(outsrc, 'w').write('''int func%s() {
+with open(outhdr, 'w') as f:
+    f.write('int func%s();\n' % val)
+with open(outsrc, 'w') as f:
+    f.write('''int func%s() {
     return 0;
 }
 ''' % val)
diff --git a/test cases/common/72 build always/version_gen.py b/test cases/common/72 build always/version_gen.py
index c82678db6..d7b01ca1a 100755
--- a/test cases/common/72 build always/version_gen.py	
+++ b/test cases/common/72 build always/version_gen.py	
@@ -14,14 +14,17 @@ def generate(infile, outfile, fallback):
             version = stdo.decode().strip()
     except:
         pass
-    newdata = open(infile).read().replace('@VERSION@', version)
+    with open(infile) as f:
+        newdata = f.read().replace('@VERSION@', version)
     try:
-        olddata = open(outfile).read()
+        with open(outfile) as f:
+            olddata = f.read()
         if olddata == newdata:
             return
     except:
         pass
-    open(outfile, 'w').write(newdata)
+    with open(outfile, 'w') as f:
+        f.write(newdata)
 
 if __name__ == '__main__':
     infile = sys.argv[1]
diff --git a/test cases/common/76 configure file in custom target/src/mycompiler.py b/test cases/common/76 configure file in custom target/src/mycompiler.py
index d5dcab54f..b00c862db 100644
--- a/test cases/common/76 configure file in custom target/src/mycompiler.py	
+++ b/test cases/common/76 configure file in custom target/src/mycompiler.py	
@@ -2,7 +2,8 @@
 
 import sys
 
-ifile = open(sys.argv[1])
-if ifile.readline().strip() != '42':
-    print('Incorrect input')
-open(sys.argv[2], 'w').write('Success\n')
+with open(sys.argv[1]) as ifile:
+    if ifile.readline().strip() != '42':
+        print('Incorrect input')
+with open(sys.argv[2], 'w') as ofile:
+    ofile.write('Success\n')
diff --git a/test cases/common/78 ctarget dependency/gen1.py b/test cases/common/78 ctarget dependency/gen1.py
index 64b8e6d69..0fa6ea1eb 100755
--- a/test cases/common/78 ctarget dependency/gen1.py	
+++ b/test cases/common/78 ctarget dependency/gen1.py	
@@ -6,5 +6,7 @@ import time, sys
 # is missing.
 time.sleep(0.5)
 
-contents = open(sys.argv[1], 'r').read()
-open(sys.argv[2], 'w').write(contents)
+with open(sys.argv[1], 'r') as f:
+    contents = f.read()
+with open(sys.argv[2], 'w') as f:
+    f.write(contents)
diff --git a/test cases/common/78 ctarget dependency/gen2.py b/test cases/common/78 ctarget dependency/gen2.py
index 3a8be7df7..b087b02cc 100755
--- a/test cases/common/78 ctarget dependency/gen2.py	
+++ b/test cases/common/78 ctarget dependency/gen2.py	
@@ -6,4 +6,5 @@ from glob import glob
 files = glob(os.path.join(sys.argv[1], '*.tmp'))
 assert(len(files) == 1)
 
-open(sys.argv[2], 'w').write(open(files[0], 'r').read())
+with open(files[0], 'r') as ifile, open(sys.argv[2], 'w') as ofile:
+    ofile.write(ifile.read())
diff --git a/test cases/common/93 private include/stlib/compiler.py b/test cases/common/93 private include/stlib/compiler.py
index 3e74c8816..98dbe46fa 100755
--- a/test cases/common/93 private include/stlib/compiler.py	
+++ b/test cases/common/93 private include/stlib/compiler.py	
@@ -26,5 +26,7 @@ hfile = os.path.join(outdir, base + '.h')
 c_code = c_templ % (base, base)
 h_code = h_templ % base
 
-open(cfile, 'w').write(c_code)
-open(hfile, 'w').write(h_code)
+with open(cfile, 'w') as f:
+    f.write(c_code)
+with open(hfile, 'w') as f:
+    f.write(h_code)
diff --git a/test cases/common/98 gen extra/srcgen.py b/test cases/common/98 gen extra/srcgen.py
index 55e777e0f..73bc33743 100755
--- a/test cases/common/98 gen extra/srcgen.py	
+++ b/test cases/common/98 gen extra/srcgen.py	
@@ -19,8 +19,10 @@ c_templ = '''int %s() {
 
 options = parser.parse_args(sys.argv[1:])
 
-funcname = open(options.input).readline().strip()
+with open(options.input) as f:
+    funcname = f.readline().strip()
 if options.upper:
     funcname = funcname.upper()
 
-open(options.output, 'w').write(c_templ % funcname)
+with open(options.output, 'w') as f:
+    f.write(c_templ % funcname)
diff --git a/tools/ac_converter.py b/tools/ac_converter.py
index 571481e1d..e88f2e2bb 100755
--- a/tools/ac_converter.py
+++ b/tools/ac_converter.py
@@ -25,28 +25,6 @@ that are unrelated to configure checks.
 
 import sys
 
-print('''cc = meson.get_compiler('c')
-cdata = configuration_data()''')
-
-print('check_headers = [')
-
-for line in open(sys.argv[1]):
-    line = line.strip()
-    if line.startswith('#mesondefine') and \
-       line.endswith('_H'):
-        token = line.split()[1]
-        tarr = token.split('_')[1:-1]
-        tarr = [x.lower() for x in tarr]
-        hname = '/'.join(tarr) + '.h'
-        print("  ['%s', '%s']," % (token, hname))
-print(']\n')
-
-print('''foreach h : check_headers
-  if cc.has_header(h.get(1))
-    cdata.set(h.get(0), 1)
-  endif
-endforeach
-''')
 
 # Add stuff here as it is encountered.
 function_data = \
@@ -242,18 +220,71 @@ function_data = \
      'HAVE_PTHREAD_SET_NAME_NP': ('pthread_set_name_np', 'pthread.h'),
     }
 
-print('check_functions = [')
+headers = []
+functions = []
+sizes = []
+with open(sys.argv[1]) as f:
+    for line in f:
+        line = line.strip()
+        arr = line.split()
+
+        # Check for headers.
+        if line.startswith('#mesondefine') and line.endswith('_H'):
+            token = line.split()[1]
+            tarr = token.split('_')[1:-1]
+            tarr = [x.lower() for x in tarr]
+            hname = '/'.join(tarr) + '.h'
+            headers.append((token, hname))
+
+        # Check for functions.
+        try:
+            token = arr[1]
+            if token in function_data:
+                fdata = function_data[token]
+                functions.append((token, fdata[0], fdata[1]))
+            elif token.startswith('HAVE_') and not token.endswith('_H'):
+                functions.append((token, ))
+        except Exception:
+            pass
+
+        # Check for sizeof tests.
+        if len(arr) != 2:
+            continue
+        elem = arr[1]
+        if elem.startswith('SIZEOF_'):
+            typename = elem.split('_', 1)[1] \
+                .replace('_P', '*') \
+                .replace('_', ' ') \
+                .lower() \
+                .replace('size t', 'size_t')
+            sizes.append((elem, typename))
 
-for line in open(sys.argv[1]):
-    try:
-        token = line.split()[1]
-        if token in function_data:
-            fdata = function_data[token]
-            print("  ['%s', '%s', '#include<%s>']," % (token, fdata[0], fdata[1]))
-        elif token.startswith('HAVE_') and not token.endswith('_H'):
-            print('# check token', token)
-    except Exception:
-        pass
+print('''cc = meson.get_compiler('c')
+cdata = configuration_data()''')
+
+# Convert header checks.
+
+print('check_headers = [')
+for token, hname in headers:
+    print("  ['%s', '%s']," % (token, hname))
+print(']\n')
+
+print('''foreach h : check_headers
+  if cc.has_header(h.get(1))
+    cdata.set(h.get(0), 1)
+  endif
+endforeach
+''')
+
+# Convert function checks.
+
+print('check_functions = [')
+for token in functions:
+    if len(func) == 3:
+        token, fdata0, fdata1 = token
+        print("  ['%s', '%s', '#include<%s>']," % (token, fdata0, fdata1))
+    else:
+        print('# check token', token)
 print(']\n')
 
 print('''foreach f : check_functions
@@ -265,14 +296,8 @@ endforeach
 
 # Convert sizeof checks.
 
-for line in open(sys.argv[1]):
-    arr = line.strip().split()
-    if len(arr) != 2:
-        continue
-    elem = arr[1]
-    if elem.startswith('SIZEOF_'):
-        typename = elem.split('_', 1)[1].replace('_P', '*').replace('_', ' ').lower().replace('size t', 'size_t')
-        print("cdata.set('%s', cc.sizeof('%s'))" % (elem, typename))
+for elem, typename in size:
+    print("cdata.set('%s', cc.sizeof('%s'))" % (elem, typename))
 
 print('''
 configure_file(input : 'config.h.meson',
diff --git a/tools/cmake2meson.py b/tools/cmake2meson.py
index 098a6e0c8..7465d4513 100755
--- a/tools/cmake2meson.py
+++ b/tools/cmake2meson.py
@@ -252,39 +252,46 @@ class Converter:
             subdir = self.cmake_root
         cfile = os.path.join(subdir, 'CMakeLists.txt')
         try:
-            cmakecode = open(cfile).read()
+            with open(cfile) as f:
+                cmakecode = f.read()
         except FileNotFoundError:
             print('\nWarning: No CMakeLists.txt in', subdir, '\n')
             return
         p = Parser(cmakecode)
-        outfile = open(os.path.join(subdir, 'meson.build'), 'w')
-        for t in p.parse():
-            if t.name == 'add_subdirectory':
-                #print('\nRecursing to subdir', os.path.join(self.cmake_root, t.args[0].value), '\n')
-                self.convert(os.path.join(subdir, t.args[0].value))
-                #print('\nReturning to', self.cmake_root, '\n')
-            self.write_entry(outfile, t)
+        with open(os.path.join(subdir, 'meson.build'), 'w') as outfile:
+            for t in p.parse():
+                if t.name == 'add_subdirectory':
+                    # print('\nRecursing to subdir',
+                    #       os.path.join(self.cmake_root, t.args[0].value),
+                    #       '\n')
+                    self.convert(os.path.join(subdir, t.args[0].value))
+                    # print('\nReturning to', self.cmake_root, '\n')
+                self.write_entry(outfile, t)
         if subdir == self.cmake_root and len(self.options) > 0:
             self.write_options()
 
     def write_options(self):
-        optfile = open(os.path.join(self.cmake_root, 'meson_options.txt'), 'w')
-        for o in self.options:
-            (optname, description, default) = o
-            if default is None:
-                defaultstr = ''
-            else:
-                if default == 'OFF':
-                    typestr = ' type : boolean,'
-                    default = 'false'
-                elif default == 'ON':
-                    default = 'true'
-                    typestr = ' type : boolean,'
+        filename = os.path.join(self.cmake_root, 'meson_options.txt')
+        with open(filename, 'w') as optfile:
+            for o in self.options:
+                (optname, description, default) = o
+                if default is None:
+                    defaultstr = ''
                 else:
-                    typestr = ' type : string,'
-                defaultstr = ' value : %s,' % default
-            line = "option(%s,%s%s description : '%s')\n" % (optname, typestr, defaultstr, description)
-            optfile.write(line)
+                    if default == 'OFF':
+                        typestr = ' type : boolean,'
+                        default = 'false'
+                    elif default == 'ON':
+                        default = 'true'
+                        typestr = ' type : boolean,'
+                    else:
+                        typestr = ' type : string,'
+                    defaultstr = ' value : %s,' % default
+                line = "option(%s,%s%s description : '%s')\n" % (optname,
+                                                                 typestr,
+                                                                 defaultstr,
+                                                                 description)
+                optfile.write(line)
 
 if __name__ == '__main__':
     if len(sys.argv) != 2: