Substitute output file then check for conflict.

Fixes Issue #4323.
The check to see if a call to configure_file() overwrites the output of
a preceding call should perform the substitution for the output file
before doing the check.

Added tests to ensure the proper behaviour.

mesonbuild/interpreter.py

@@ -3540,9 +3540,13 @@ root and issuing %s.
             raise InterpreterException('@INPUT@ used as command argument, but no input file specified.')
         # Validate output
         output = kwargs['output']
-        ofile_rpath = os.path.join(self.subdir, output)
         if not isinstance(output, str):
             raise InterpreterException('Output file name must be a string')
+        if ifile_abs:
+            values = mesonlib.get_filenames_templates_dict([ifile_abs], None)
+            outputs = mesonlib.substitute_values([output], values)
+            output = outputs[0]
+        ofile_rpath = os.path.join(self.subdir, output)
         if ofile_rpath in self.configure_file_outputs:
             mesonbuildfile = os.path.join(self.subdir, 'meson.build')
             current_call = "{}:{}".format(mesonbuildfile, self.current_lineno)
@@ -3550,10 +3554,6 @@ root and issuing %s.
             mlog.warning('Output file', mlog.bold(ofile_rpath, True), 'for configure_file() at', current_call, 'overwrites configure_file() output at', first_call)
         else:
             self.configure_file_outputs[ofile_rpath] = self.current_lineno
-        if ifile_abs:
-            values = mesonlib.get_filenames_templates_dict([ifile_abs], None)
-            outputs = mesonlib.substitute_values([output], values)
-            output = outputs[0]
         if os.path.dirname(output) != '':
             raise InterpreterException('Output file name must not contain a subdirectory.')
         (ofile_path, ofile_fname) = os.path.split(os.path.join(self.subdir, output))

run_unittests.py

@@ -2682,6 +2682,8 @@ recommended as it is not supported on some platforms''')
         self.assertRegex(out, "WARNING:.*\"double_output.txt\".*overwrites")
         self.assertRegex(out, "WARNING:.*\"subdir.double_output2.txt\".*overwrites")
         self.assertNotRegex(out, "WARNING:.*no_write_conflict.txt.*overwrites")
+        self.assertNotRegex(out, "WARNING:.*@BASENAME@.*overwrites")
+        self.assertRegex(out, "WARNING:.*\"sameafterbasename\".*overwrites")
         # No warnings about empty configuration data objects passed to files with substitutions
         self.assertNotRegex(out, "WARNING:.*empty configuration_data.*nosubst-nocopy1.txt.in")
         self.assertNotRegex(out, "WARNING:.*empty configuration_data.*nosubst-nocopy2.txt.in")

test cases/common/14 configure file/meson.build

@@ -218,6 +218,30 @@ configure_file(
   output: 'no_write_conflict.txt',
   configuration: conf)
 
+# Test that @BASENAME@ is substituted before checking and does not create a warning.
+configure_file(
+  input: 'differentafterbasename1.in',
+  output: '@BASENAME@',
+  configuration: conf
+)
+configure_file(
+  input: 'differentafterbasename2.in',
+  output: '@BASENAME@',
+  configuration: conf
+)
+
+# Test that @BASENAME@ is substituted before checking and does create a warning on conflict.
+configure_file(
+  input: 'sameafterbasename.in',
+  output: '@BASENAME@',
+  configuration: conf
+)
+configure_file(
+  input: 'sameafterbasename.in2',
+  output: '@BASENAME@',
+  configuration: conf
+)
+
 test('configure-file', test_file)
 
 cdata = configuration_data()