interpreter: extract_objects provides a valid source

This ensures that there is no warnings when running meson on
test cases/common/22 object extraction.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

mesonbuild/interpreter/interpreter.py

@@ -90,11 +90,12 @@ if T.TYPE_CHECKING:
 
     # Input source types passed to Targets
     SourceInputs = T.Union[mesonlib.File, build.GeneratedList, build.BuildTarget, build.BothLibraries,
-                           build.CustomTargetIndex, build.CustomTarget, build.GeneratedList, str]
-    # Input source types passed to the build.Target5 classes
+                           build.CustomTargetIndex, build.CustomTarget, build.GeneratedList,
+                           build.ExtractedObjects, str]
+    # Input source types passed to the build.Target classes
     SourceOutputs = T.Union[mesonlib.File, build.GeneratedList,
                             build.BuildTarget, build.CustomTargetIndex, build.CustomTarget,
-                            build.GeneratedList]
+                            build.ExtractedObjects, build.GeneratedList]
 
 
 def stringifyUserArguments(args, quote=False):
@@ -2573,7 +2574,7 @@ Try setting b_lundef to false instead.'''.format(self.coredata.options[OptionKey
                 results.append(s)
             elif isinstance(s, (build.GeneratedList, build.BuildTarget,
                                 build.CustomTargetIndex, build.CustomTarget,
-                                build.GeneratedList)):
+                                build.ExtractedObjects)):
                 results.append(s)
             else:
                 raise InterpreterException(f'Source item is {s!r} instead of '

unittests/allplatformstests.py

@@ -3540,6 +3540,12 @@ class AllPlatformTests(BasePlatformTests):
             self.build()
             self.run_tests()
 
+    def test_extract_objects_custom_target_no_warning(self):
+        testdir = os.path.join(self.common_test_dir, '22 object extraction')
+
+        out = self.init(testdir)
+        self.assertNotRegex(out, "WARNING:.*can't be converted to File object")
+
     def test_multi_output_custom_target_no_warning(self):
         testdir = os.path.join(self.common_test_dir, '228 custom_target source')