extract_objects: skip headers when building custom_target command line

As seen in the testcase, passing objects to custom_target does not work
if headers are passed extract_objects(), or if extract_all_objects() is used
and the sources include any header files.  To fix this, use the code that
already exists for unity build to filter out the nonexistent ".h.o" files.
This already gives for free the handling of genlist, which was mentioned
in a TODO comment.

1 files changed, 6 insertions, 4 deletions

diff --git a/mesonbuild/build.py b/mesonbuild/build.py
index 436a55d..0a792fc 100644
--- a/mesonbuild/build.py
+++ b/mesonbuild/build.py
@@ -375,7 +375,8 @@ class ExtractedObjects:
         r = '<{0} {1!r}: {2}>'
         return r.format(self.__class__.__name__, self.target.name, self.srclist)
 
-    def classify_all_sources(self, sources, generated_sources):
+    @staticmethod
+    def get_sources(sources, generated_sources):
         # Merge sources and generated sources
         sources = list(sources)
         for gensrc in generated_sources:
@@ -386,8 +387,10 @@ class ExtractedObjects:
                 sources.append(s)
 
         # Filter out headers and all non-source files
-        sources = [s for s in sources if environment.is_source(s) and not environment.is_header(s)]
+        return [s for s in sources if environment.is_source(s) and not environment.is_header(s)]
 
+    def classify_all_sources(self, sources, generated_sources):
+        sources = self.get_sources(sources, generated_sources)
         return classify_unity_sources(self.target.compilers.values(), sources)
 
     def check_unity_compatible(self):
@@ -407,10 +410,9 @@ class ExtractedObjects:
                                      'the object files for each compiler at once.')
 
     def get_outputs(self, backend):
-        # TODO: Consider if we need to handle genlist here
         return [
             backend.object_filename_from_source(self.target, source)
-            for source in self.srclist
+            for source in self.get_sources(self.srclist, self.genlist)
         ]
 
 class EnvironmentVariables: