interpreter: allow extract_objects to receive generated sources

Fixes: #8333

docs/markdown/snippets/extract-more-objects.md

@@ -0,0 +1,4 @@
+## ``extract_objects()`` supports generated sources
+
+Custom targets or generated files (returned by ``generator.process()``)
+can now be passed to ``extract_objects()``.

mesonbuild/build.py

@@ -987,21 +987,30 @@ class BuildTarget(Target):
             if t in self.kwargs:
                 self.kwargs[t] = listify(self.kwargs[t], flatten=True)
 
-    def extract_objects(self, srclist: T.List['FileOrString']) -> ExtractedObjects:
-        obj_src: T.List['File'] = []
+    def extract_objects(self, srclist: T.List[T.Union['FileOrString', 'GeneratedTypes']]) -> ExtractedObjects:
         sources_set = set(self.sources)
+        generated_set = set(self.generated)
+
+        obj_src: T.List['File'] = []
+        obj_gen: T.List['GeneratedTypes'] = []
         for src in srclist:
-            if isinstance(src, str):
-                src = File(False, self.subdir, src)
-            elif isinstance(src, File):
-                FeatureNew.single_use('File argument for extract_objects', '0.50.0', self.subproject)
+            if isinstance(src, (str, File)):
+                if isinstance(src, str):
+                    src = File(False, self.subdir, src)
+                else:
+                    FeatureNew.single_use('File argument for extract_objects', '0.50.0', self.subproject)
+                if src not in sources_set:
+                    raise MesonException(f'Tried to extract unknown source {src}.')
+                obj_src.append(src)
+            elif isinstance(src, (CustomTarget, CustomTargetIndex, GeneratedList)):
+                FeatureNew.single_use('Generated sources for extract_objects', '0.61.0', self.subproject)
+                target = src.target if isinstance(src, CustomTargetIndex) else src
+                if src not in generated_set and target not in generated_set:
+                    raise MesonException(f'Tried to extract unknown source {target.get_basename()}.')
+                obj_gen.append(src)
             else:
-                raise MesonException(f'Object extraction arguments must be strings or Files (got {type(src).__name__}).')
-            # FIXME: It could be a generated source
-            if src not in sources_set:
-                raise MesonException(f'Tried to extract unknown source {src}.')
-            obj_src.append(src)
-        return ExtractedObjects(self, obj_src)
+                raise MesonException(f'Object extraction arguments must be strings, Files or targets (got {type(src).__name__}).')
+        return ExtractedObjects(self, obj_src, obj_gen)
 
     def extract_all_objects(self, recursive: bool = True) -> ExtractedObjects:
         return ExtractedObjects(self, self.sources, self.generated, self.objects,

mesonbuild/interpreter/interpreterobjects.py

@@ -828,8 +828,8 @@ class BuildTargetHolder(ObjectHolder[_BuildTarget]):
         return self.interpreter.backend.get_target_dir(self._target_object)
 
     @noKwargs
-    @typed_pos_args('extract_objects', varargs=(mesonlib.File, str))
-    def extract_objects_method(self, args: T.Tuple[T.List[mesonlib.FileOrString]], kwargs: TYPE_nkwargs) -> build.ExtractedObjects:
+    @typed_pos_args('extract_objects', varargs=(mesonlib.File, str, build.CustomTarget, build.CustomTargetIndex, build.GeneratedList))
+    def extract_objects_method(self, args: T.Tuple[T.List[T.Union[mesonlib.FileOrString, 'build.GeneratedTypes']]], kwargs: TYPE_nkwargs) -> build.ExtractedObjects:
         return self._target_object.extract_objects(args[0])
 
     @noPosargs

test cases/common/22 object extraction/create-source.py

@@ -0,0 +1,3 @@
+#! /usr/bin/env python3
+import sys
+print(f'#include "{sys.argv[1]}"')

test cases/common/22 object extraction/meson.build

@@ -20,6 +20,18 @@ else
   e5 = executable('main5', 'main.c', objects : obj5)
   e6 = executable('main6', 'main.c', objects : obj6)
 
+  ct_src = custom_target('lib3.c', output: 'lib3.c', capture: true,
+                         command: [find_program('create-source.py'), 'lib.c'])
+  lib3 = library('somelib3', ct_src)
+  e7 = executable('main7', 'main.c', objects: lib3.extract_objects(ct_src[0]))
+  e8 = executable('main8', 'main.c', objects: lib3.extract_objects(ct_src))
+
+  gen = generator(find_program('create-source.py'), arguments: ['@INPUT@'],
+                  output: '@BASENAME@4.c', capture: true)
+  gen_src = gen.process('lib.c')
+  lib4 = library('somelib4', gen_src)
+  e9 = executable('main9', 'main.c', objects: lib4.extract_objects(gen_src))
+
   custom_target('custom_target with object inputs', output: 'objs',
                 input: [obj1, obj2, obj3, obj5, obj6],
                 build_by_default: true,
@@ -32,4 +44,7 @@ else
   test('extraction test 4', e4)
   test('extraction test 5', e5)
   test('extraction test 6', e6)
+  test('extraction test 7', e7)
+  test('extraction test 8', e8)
+  test('extraction test 9', e9)
 endif