[libclang/C++] Fix clang_File_isEqual for in-memory files

[DeinAlptraum]

Add tests for clang_File_isEqual (on-disk and in-memory)

[llvmbot]

@llvm/pr-subscribers-clang

Author: Jannick Kremer (DeinAlptraum)

Changes

Add tests for clang_File_isEqual (on-disk and in-memory)

---

Full diff: https://github.com/llvm/llvm-project/pull/135773.diff

1 Files Affected:

• (modified) clang/unittests/libclang/LibclangTest.cpp (+49)

diff --git a/clang/unittests/libclang/LibclangTest.cpp b/clang/unittests/libclang/LibclangTest.cpp
index 6de4d02bf74f4..b2a87d240e56e 100644
--- a/clang/unittests/libclang/LibclangTest.cpp
+++ b/clang/unittests/libclang/LibclangTest.cpp
@@ -1410,3 +1410,52 @@ TEST_F(LibclangRewriteTest, RewriteRemove) {
   ASSERT_EQ(clang_CXRewriter_overwriteChangedFiles(Rew), 0);
   EXPECT_EQ(getFileContent(Filename), "int () { return 0; }");
 }
+
+TEST_F(LibclangParseTest, FileEqual) {
+  std::string AInc = "a.inc", BInc = "b.inc", Main = "main.cpp";
+  WriteFile(Main, "int a[] = {\n"
+                  "    #include \"a.inc\"\n"
+                  "};\n"
+                  "int b[] = {\n"
+                  "    #include \"b.inc\"\n"
+                  "};");
+  WriteFile(AInc, "1,2,3");
+  WriteFile(BInc, "1,2,3");
+
+  ClangTU = clang_parseTranslationUnit(Index, Main.c_str(), nullptr, 0, nullptr,
+                                       0, TUFlags);
+
+  CXFile AFile = clang_getFile(ClangTU, AInc.c_str()),
+         AFile2 = clang_getFile(ClangTU, AInc.c_str()),
+         BFile = clang_getFile(ClangTU, BInc.c_str()),
+         MainFile = clang_getFile(ClangTU, Main.c_str());
+
+  ASSERT_FALSE(clang_File_isEqual(MainFile, AFile));
+  ASSERT_FALSE(clang_File_isEqual(AFile, BFile));
+  ASSERT_TRUE(clang_File_isEqual(AFile, AFile2));
+}
+
+TEST_F(LibclangParseTest, FileEqualInMemory) {
+  std::string AInc = "a.inc", BInc = "b.inc", Main = "main.cpp";
+  MapUnsavedFile(Main, "int a[] = {\n"
+                       "    #include \"a.inc\"\n"
+                       "};\n"
+                       "int b[] = {\n"
+                       "    #include \"b.inc\"\n"
+                       "};");
+  MapUnsavedFile(AInc, "1,2,3");
+  MapUnsavedFile(BInc, "1,2,3");
+
+  ClangTU = clang_parseTranslationUnit(Index, UnsavedFiles[0].Filename, nullptr,
+                                       0, &UnsavedFiles.front(),
+                                       UnsavedFiles.size(), TUFlags);
+
+  CXFile AFile = clang_getFile(ClangTU, UnsavedFiles[1].Filename),
+         AFile2 = clang_getFile(ClangTU, UnsavedFiles[1].Filename),
+         BFile = clang_getFile(ClangTU, UnsavedFiles[2].Filename),
+         MainFile = clang_getFile(ClangTU, UnsavedFiles[0].Filename);
+
+  ASSERT_FALSE(clang_File_isEqual(MainFile, AFile));
+  ASSERT_FALSE(clang_File_isEqual(AFile, BFile));
+  ASSERT_TRUE(clang_File_isEqual(AFile, AFile2));
+}

[DeinAlptraum]

@AaronBallman this is the fix PR for the bug we discussed at #130383 (comment)

The first test is for completeness' sake, the second one (with in-memory files) fails without the fix

[DeinAlptraum]

Also cc @Endilll

[Endilll]

LGTM, but how this fares against our stability guarantees for libclang APIs? Do we need clang_File_isEqual2?

[DeinAlptraum]

Have we documented exact requirements for this anywhere?
I'm not sure what the point of stability would be here: clang_File_isEqual returns True for all comparisons of in-memory files, which just makes this useless in practice. Any code that relies on this would be wrong to begin with...

[DeinAlptraum]

@AaronBallman ping/reminder for a review 🙇

[AaronBallman]

LGTM, thank you for the fix!

[AaronBallman]

LGTM, but how this fares against our stability guarantees for libclang APIs? Do we need clang_File_isEqual2?

I think this is a bug fix and so it meets our requirements. The ABI is stable, but we can fix logic bugs.