Bug 1733308 - Forbid sources files with the same base name. r=firefox-build-system-reviewers,andi

While the build system could be improved to actually support those
cases, because of all the legacy things involved, it would be a lot more
work for a low reward.

Instead, we forbid them, which allows to remove the non-unified builds
exception in xpcom/rust/gtest.

Differential Revision: https://phabricator.services.mozilla.com/D127035

python/mozbuild/mozbuild/frontend/emitter.py

@@ -621,7 +621,7 @@ class TreeMetadataEmitter(LoggingMixin):
             dependencies,
             features,
             is_gkrust,
-            **static_args
+            **static_args,
         )
 
     def _handle_gn_dirs(self, context):
@@ -989,6 +989,22 @@ class TreeMetadataEmitter(LoggingMixin):
             wasm_linkables.append(lib)
             self._wasm_compile_dirs.add(context.objdir)
 
+        seen = {}
+        for symbol in ("SOURCES", "UNIFIED_SOURCES"):
+            for src in context.get(symbol, []):
+                basename = os.path.splitext(os.path.basename(src))[0]
+                if basename in seen:
+                    other_src, where = seen[basename]
+                    extra = ""
+                    if "UNIFIED_SOURCES" in (symbol, where):
+                        extra = " in non-unified builds"
+                    raise SandboxValidationError(
+                        f"{src} from {symbol} would have the same object name "
+                        f"as {other_src} from {where}{extra}.",
+                        context,
+                    )
+                seen[basename] = (src, symbol)
+
         # Only emit sources if we have linkables defined in the same context.
         # Note the linkables are not emitted in this function, but much later,
         # after aggregation (because of e.g. USE_LIBS processing).

python/mozbuild/mozbuild/test/backend/data/database/moz.build

@@ -11,4 +11,4 @@ def Library(name):
 
 Library("dummy")
 
-SOURCES = ["bar.c", "bar.cpp", "foo.c", "foo.cpp"]
+SOURCES = ["bar.c", "baz.cpp", "foo.c", "qux.cpp"]

python/mozbuild/mozbuild/test/backend/data/sources/moz.build

@@ -14,13 +14,13 @@ Library("dummy")
 SOURCES += ["bar.s", "foo.asm"]
 
 HOST_SOURCES += ["bar.cpp", "foo.cpp"]
-HOST_SOURCES += ["bar.c", "foo.c"]
+HOST_SOURCES += ["baz.c", "qux.c"]
 
-SOURCES += ["bar.c", "foo.c"]
+SOURCES += ["baz.c", "qux.c"]
 
-SOURCES += ["bar.mm", "foo.mm"]
+SOURCES += ["fuga.mm", "hoge.mm"]
 
-SOURCES += ["baz.S", "foo.S"]
+SOURCES += ["titi.S", "toto.S"]
 
 WASM_SOURCES += ["bar.cpp"]
-WASM_SOURCES += ["bar.c"]
+WASM_SOURCES += ["baz.c"]

python/mozbuild/mozbuild/test/backend/test_database.py

@@ -42,17 +42,17 @@ class TestCompileDBBackends(BackendTester):
             },
             {
                 "directory": topobjdir,
-                "command": "clang++ -o /dev/null -c -ferror-limit=0 {}/bar.cpp".format(
+                "command": "clang++ -o /dev/null -c -ferror-limit=0 {}/baz.cpp".format(
                     topsrcdir
                 ),
-                "file": "{}/bar.cpp".format(topsrcdir),
+                "file": "{}/baz.cpp".format(topsrcdir),
             },
             {
                 "directory": topobjdir,
-                "command": "clang++ -o /dev/null -c -ferror-limit=0 {}/foo.cpp".format(
+                "command": "clang++ -o /dev/null -c -ferror-limit=0 {}/qux.cpp".format(
                     topsrcdir
                 ),
-                "file": "{}/foo.cpp".format(topsrcdir),
+                "file": "{}/qux.cpp".format(topsrcdir),
             },
         ]
 

python/mozbuild/mozbuild/test/backend/test_recursivemake.py

@@ -376,18 +376,18 @@ class TestRecursiveMakeBackend(BackendTester):
 
         expected = {
             "ASFILES": ["ASFILES += $(srcdir)/bar.s", "ASFILES += $(srcdir)/foo.asm"],
-            "CMMSRCS": ["CMMSRCS += $(srcdir)/bar.mm", "CMMSRCS += $(srcdir)/foo.mm"],
-            "CSRCS": ["CSRCS += $(srcdir)/bar.c", "CSRCS += $(srcdir)/foo.c"],
+            "CMMSRCS": ["CMMSRCS += $(srcdir)/fuga.mm", "CMMSRCS += $(srcdir)/hoge.mm"],
+            "CSRCS": ["CSRCS += $(srcdir)/baz.c", "CSRCS += $(srcdir)/qux.c"],
             "HOST_CPPSRCS": [
                 "HOST_CPPSRCS += $(srcdir)/bar.cpp",
                 "HOST_CPPSRCS += $(srcdir)/foo.cpp",
             ],
             "HOST_CSRCS": [
-                "HOST_CSRCS += $(srcdir)/bar.c",
-                "HOST_CSRCS += $(srcdir)/foo.c",
+                "HOST_CSRCS += $(srcdir)/baz.c",
+                "HOST_CSRCS += $(srcdir)/qux.c",
             ],
-            "SSRCS": ["SSRCS += $(srcdir)/baz.S", "SSRCS += $(srcdir)/foo.S"],
-            "WASM_CSRCS": ["WASM_CSRCS += $(srcdir)/bar.c"],
+            "SSRCS": ["SSRCS += $(srcdir)/titi.S", "SSRCS += $(srcdir)/toto.S"],
+            "WASM_CSRCS": ["WASM_CSRCS += $(srcdir)/baz.c"],
             "WASM_CPPSRCS": ["WASM_CPPSRCS += $(srcdir)/bar.cpp"],
         }
 

python/mozbuild/mozbuild/test/frontend/data/asflags/moz.build

@@ -10,6 +10,6 @@ def Library(name):
 
 Library("dummy")
 
-SOURCES += ["test1.c", "test1.S"]
+SOURCES += ["test1.c", "test2.S"]
 
 ASFLAGS += ["-no-integrated-as"]

python/mozbuild/mozbuild/test/frontend/data/object-conflicts/1/moz.build

@@ -0,0 +1,4 @@
+SOURCES += [
+    "Test.c",
+    "Test.cpp",
+]

python/mozbuild/mozbuild/test/frontend/data/object-conflicts/2/moz.build

@@ -0,0 +1,4 @@
+SOURCES += [
+    "subdir/Test.cpp",
+    "Test.cpp",
+]

python/mozbuild/mozbuild/test/frontend/data/object-conflicts/3/moz.build

@@ -0,0 +1,7 @@
+SOURCES += [
+    "Test.c",
+]
+
+UNIFIED_SOURCES += [
+    "Test.cpp",
+]

python/mozbuild/mozbuild/test/frontend/data/object-conflicts/4/moz.build

@@ -0,0 +1,4 @@
+UNIFIED_SOURCES += [
+    "Test.c",
+    "Test.cpp",
+]

python/mozbuild/mozbuild/test/frontend/test_emitter.py

@@ -1514,6 +1514,40 @@ class TestEmitterBasic(unittest.TestCase):
             )
             self.assertFalse(sources.have_unified_mapping)
 
+    def test_object_conflicts(self):
+        """Test that object name conflicts are detected."""
+        reader = self.reader("object-conflicts/1")
+        with self.assertRaisesRegex(
+            SandboxValidationError,
+            "Test.cpp from SOURCES would have the same object name as"
+            " Test.c from SOURCES\.",
+        ):
+            self.read_topsrcdir(reader)
+
+        reader = self.reader("object-conflicts/2")
+        with self.assertRaisesRegex(
+            SandboxValidationError,
+            "Test.cpp from SOURCES would have the same object name as"
+            " subdir/Test.cpp from SOURCES\.",
+        ):
+            self.read_topsrcdir(reader)
+
+        reader = self.reader("object-conflicts/3")
+        with self.assertRaisesRegex(
+            SandboxValidationError,
+            "Test.cpp from UNIFIED_SOURCES would have the same object name as"
+            " Test.c from SOURCES in non-unified builds\.",
+        ):
+            self.read_topsrcdir(reader)
+
+        reader = self.reader("object-conflicts/4")
+        with self.assertRaisesRegex(
+            SandboxValidationError,
+            "Test.cpp from UNIFIED_SOURCES would have the same object name as"
+            " Test.c from UNIFIED_SOURCES in non-unified builds\.",
+        ):
+            self.read_topsrcdir(reader)
+
     def test_final_target_pp_files(self):
         """Test that FINAL_TARGET_PP_FILES works properly."""
         reader = self.reader("dist-files")

xpcom/rust/gtest/moz.build

@@ -6,11 +6,9 @@
 
 UNIFIED_SOURCES += [
     "bench-collections/Bench.cpp",
-    "moz_task/Test.cpp",
-    "nsstring/Test.cpp",
-    "xpcom/Test.cpp",
+    "moz_task/TestMozTask.cpp",
+    "nsstring/TestnsString.cpp",
+    "xpcom/TestXpcom.cpp",
 ]
 
 FINAL_LIBRARY = "xul-gtest"
-
-REQUIRES_UNIFIED_BUILD = True