Fix '# Visual Studio <>' comment in sln files with VS backend

such that Visual Studio Version Selector works.

mesonbuild/backend/vs2010backend.py

@@ -98,6 +98,8 @@ class Vs2010Backend(backends.Backend):
         super().__init__(build, interpreter)
         self.name = 'vs2010'
         self.project_file_version = '10.0.30319.1'
+        self.sln_file_version = '11.00'
+        self.sln_version_comment = '2010'
         self.platform_toolset = None
         self.vs_version = '2010'
         self.windows_target_platform_version = None
@@ -348,10 +350,11 @@ class Vs2010Backend(backends.Backend):
     def generate_solution(self, sln_filename, projlist):
         default_projlist = self.get_build_by_default_targets()
         sln_filename_tmp = sln_filename + '~'
-        with open(sln_filename_tmp, 'w', encoding='utf-8') as ofile:
-            ofile.write('Microsoft Visual Studio Solution File, Format '
-                        'Version 11.00\n')
-            ofile.write('# Visual Studio ' + self.vs_version + '\n')
+        # Note using the utf-8 BOM requires the blank line, otherwise Visual Studio Version Selector fails.
+        # Without the BOM, VSVS fails if there is a blank line.
+        with open(sln_filename_tmp, 'w', encoding='utf-8-sig') as ofile:
+            ofile.write('\nMicrosoft Visual Studio Solution File, Format Version %s\n' % self.sln_file_version)
+            ofile.write('# Visual Studio %s\n' % self.sln_version_comment)
             prj_templ = 'Project("{%s}") = "%s", "%s", "{%s}"\n'
             for prj in projlist:
                 coredata = self.environment.coredata

mesonbuild/backend/vs2012backend.py

@@ -24,6 +24,8 @@ class Vs2012Backend(Vs2010Backend):
         super().__init__(build, interpreter)
         self.name = 'vs2012'
         self.vs_version = '2012'
+        self.sln_file_version = '12.00'
+        self.sln_version_comment = '2012'
         if self.environment is not None:
             # TODO: we assume host == build
             comps = self.environment.coredata.compilers.host

mesonbuild/backend/vs2013backend.py

@@ -24,6 +24,8 @@ class Vs2013Backend(Vs2010Backend):
         super().__init__(build, interpreter)
         self.name = 'vs2013'
         self.vs_version = '2013'
+        self.sln_file_version = '12.00'
+        self.sln_version_comment = '2013'
         if self.environment is not None:
             # TODO: we assume host == build
             comps = self.environment.coredata.compilers.host

mesonbuild/backend/vs2015backend.py

@@ -24,6 +24,8 @@ class Vs2015Backend(Vs2010Backend):
         super().__init__(build, interpreter)
         self.name = 'vs2015'
         self.vs_version = '2015'
+        self.sln_file_version = '12.00'
+        self.sln_version_comment = '14'
         if self.environment is not None:
             # TODO: we assume host == build
             comps = self.environment.coredata.compilers.host

mesonbuild/backend/vs2017backend.py

@@ -27,6 +27,8 @@ class Vs2017Backend(Vs2010Backend):
         super().__init__(build, interpreter)
         self.name = 'vs2017'
         self.vs_version = '2017'
+        self.sln_file_version = '12.00'
+        self.sln_version_comment = '15'
         # We assume that host == build
         if self.environment is not None:
             comps = self.environment.coredata.compilers.host
@@ -59,4 +61,4 @@ class Vs2017Backend(Vs2010Backend):
         if 'c' in file_args:
             optargs = [x for x in file_args['c'] if x.startswith('/std:c')]
             if optargs:
-                ET.SubElement(clconf, 'LanguageStandard_C').text = optargs[0].replace("/std:c", "stdc")
+                ET.SubElement(clconf, 'LanguageStandard_C').text = optargs[0].replace("/std:c", "stdc")

mesonbuild/backend/vs2019backend.py

@@ -25,6 +25,8 @@ class Vs2019Backend(Vs2010Backend):
     def __init__(self, build: T.Optional[Build], interpreter: T.Optional[Interpreter]):
         super().__init__(build, interpreter)
         self.name = 'vs2019'
+        self.sln_file_version = '12.00'
+        self.sln_version_comment = 'Version 16'
         if self.environment is not None:
             comps = self.environment.coredata.compilers.host
             if comps and all(c.id == 'clang-cl' for c in comps.values()):

mesonbuild/backend/vs2022backend.py

@@ -25,6 +25,8 @@ class Vs2022Backend(Vs2010Backend):
     def __init__(self, build: T.Optional[Build], interpreter: T.Optional[Interpreter]):
         super().__init__(build, interpreter)
         self.name = 'vs2022'
+        self.sln_file_version = '12.00'
+        self.sln_version_comment = 'Version 17'
         if self.environment is not None:
             comps = self.environment.coredata.compilers.host
             if comps and all(c.id == 'clang-cl' for c in comps.values()):