configure_file: Substitute @INPUT@/@OUTPUT@/etc in command

The same substitutions and rules as custom_target().

Also generally fix it to actually work when run in a subdir and with
anything other than absolute paths for input and output files.

We now also log a message when configuring files.

Includes tests for all this.

mesonbuild/interpreter.py

@@ -2218,12 +2218,24 @@ requirements use the version keyword argument instead.''')
             raise InterpreterException('Must not specify both "configuration" '
                                        'and "command" keyword arguments since '
                                        'they are mutually exclusive.')
-        inputfile = kwargs.get('input', None)
+        # Validate input
+        inputfile = None
+        if 'input' in kwargs:
+            inputfile = kwargs['input']
+            if isinstance(inputfile, list):
+                if len(inputfile) != 1:
+                    m = "Keyword argument 'input' requires exactly one file"
+                    raise InterpreterException(m)
+                inputfile = inputfile[0]
+            if not isinstance(inputfile, (str, mesonlib.File)):
+                raise InterpreterException('Input must be a string or a file')
+            ifile_abs = os.path.join(self.environment.source_dir, self.subdir, inputfile)
+        elif 'command' in kwargs:
+            raise InterpreterException('Required keyword argument \'input\' missing')
+        # Validate output
         output = kwargs['output']
-        if inputfile is not None and not isinstance(inputfile, str):
-            raise InterpreterException('Input must be a string.')
         if not isinstance(output, str):
-            raise InterpreterException('Output must be a string.')
+            raise InterpreterException('Output file name must be a string')
         if os.path.split(output)[0] != '':
             raise InterpreterException('Output file name must not contain a subdirectory.')
         (ofile_path, ofile_fname) = os.path.split(os.path.join(self.subdir, output))
@@ -2232,6 +2244,7 @@ requirements use the version keyword argument instead.''')
             conf = kwargs['configuration']
             if not isinstance(conf, ConfigurationDataHolder):
                 raise InterpreterException('Argument "configuration" is not of type configuration_data')
+            mlog.log('Configuring', mlog.bold(output), 'using configuration')
             if inputfile is not None:
                 # Normalize the path of the conffile to avoid duplicates
                 # This is especially important to convert '/' to '\' on Windows
@@ -2239,15 +2252,19 @@ requirements use the version keyword argument instead.''')
                 if conffile not in self.build_def_files:
                     self.build_def_files.append(conffile)
                 os.makedirs(os.path.join(self.environment.build_dir, self.subdir), exist_ok=True)
-                ifile_abs = os.path.join(self.environment.source_dir, self.subdir, inputfile)
                 mesonlib.do_conf_file(ifile_abs, ofile_abs, conf.held_object)
             else:
                 mesonlib.dump_conf_header(ofile_abs, conf.held_object)
             conf.mark_used()
         elif 'command' in kwargs:
-            if 'input' not in kwargs:
-                raise InterpreterException('Required keyword input missing.')
-            res = self.func_run_command(node, kwargs['command'], {})
+            # We use absolute paths for input and output here because the cwd
+            # that the command is run from is 'unspecified', so it could change.
+            # Currently it's builddir/subdir for in_builddir else srcdir/subdir.
+            values = mesonlib.get_filenames_templates_dict([ifile_abs], [ofile_abs])
+            # Substitute @INPUT@, @OUTPUT@, etc here.
+            cmd = mesonlib.substitute_values(kwargs['command'], values)
+            mlog.log('Configuring', mlog.bold(output), 'with command')
+            res = self.func_run_command(node, cmd, {'in_builddir': True})
             if res.returncode != 0:
                 raise InterpreterException('Running configure command failed.\n%s\n%s' %
                                            (res.stdout, res.stderr))

test cases/common/16 configure file/check_file.py

@@ -0,0 +1,6 @@
+#!/usr/bin/env python3
+
+import os
+import sys
+
+assert(os.path.exists(sys.argv[1]))

test cases/common/16 configure file/generator.py

@@ -1,15 +1,17 @@
-#!/usr/bin/env python
+#!/usr/bin/env python3
 
-# On some platforms "python" points to Python 2
-# on others to Python 3. Work with both.
-
-from __future__ import print_function
 import sys, os
+from pathlib import Path
 
 if len(sys.argv) != 3:
     print("Wrong amount of parameters.")
 
-assert(os.path.exists(sys.argv[1]))
+build_dir = Path(os.environ['MESON_BUILD_ROOT'])
+subdir = Path(os.environ['MESON_SUBDIR'])
+inputf = Path(sys.argv[1])
+outputf = Path(sys.argv[2])
+
+assert(inputf.exists())
 
-with open(sys.argv[2], 'w') as ofile:
+with outputf.open('w') as ofile:
     ofile.write("#define ZERO_RESULT 0\n")

test cases/common/16 configure file/installed_files.txt

@@ -1 +1,3 @@
 usr/share/appdir/config2.h
+usr/share/appdireh/config2-1.h
+usr/share/appdirok/config2-2.h

test cases/common/16 configure file/meson.build

@@ -23,18 +23,22 @@ cfile)
 test('inctest', e)
 
 # Now generate a header file with an external script.
-genprog = find_program('python3', required : false)
-if not genprog.found()
-  genprog = find_program('python')
-endif
+genprog = import('python3').find_python()
 scriptfile = '@0@/generator.py'.format(meson.current_source_dir())
 ifile = '@0@/dummy.dat'.format(meson.current_source_dir())
 ofile = '@0@/config2.h'.format(meson.current_build_dir())
 
+check_file = find_program('check_file.py')
+# Configure in source root with command and absolute paths
 configure_file(input : 'dummy.dat',
-output : 'config2.h',
-command : [genprog, scriptfile,  ifile, ofile],
-install_dir : 'share/appdir')
+  output : 'config2.h',
+  command : [genprog, scriptfile,  ifile, ofile],
+  install_dir : 'share/appdir')
+run_command(check_file, join_paths(meson.current_build_dir(), 'config2.h'))
+
+found_script = find_program('generator.py')
+# More configure_file tests in here
+subdir('subdir')
 
 test('inctest2', executable('prog2', 'prog2.c'))
 

test cases/common/16 configure file/subdir/meson.build

@@ -0,0 +1,19 @@
+# Configure in subdir with absolute paths for input and relative for output
+configure_file(input : '../dummy.dat',
+  output : 'config2-1.h',
+  command : [genprog, scriptfile,  ifile, 'config2-1.h'],
+  install_dir : 'share/appdireh')
+run_command(check_file, join_paths(meson.current_build_dir(), 'config2-1.h'))
+
+# Configure in subdir with files() for input and relative for output
+configure_file(input : '../dummy.dat',
+  output : 'config2-2.h',
+  command : [genprog, scriptfile, files('../dummy.dat'), 'config2-2.h'],
+  install_dir : 'share/appdirok')
+run_command(check_file, join_paths(meson.current_build_dir(), 'config2-2.h'))
+
+# Configure in subdir with string templates for input and output
+configure_file(input : '../dummy.dat',
+  output : 'config2-3.h',
+  command : [found_script,  '@INPUT@', '@OUTPUT@'])
+run_command(check_file, join_paths(meson.current_build_dir(), 'config2-3.h'))