[clang][Tooling] Make the filename behaviour consistent

Dotdots were removed only when converting a relative path to absolute
one. This patch makes the behaviour consistent for absolute file paths by
removing them in that case as well. Also updates the documentation to mention
the behaviour.

Fixes https://github.com/clangd/clangd/issues/1317

Differential Revision: https://reviews.llvm.org/D137962

2 files changed, 27 insertions, 12 deletions

diff --git a/clang/lib/Tooling/JSONCompilationDatabase.cpp b/clang/lib/Tooling/JSONCompilationDatabase.cpp
index 5e18d7a..158b9a5 100644
--- a/clang/lib/Tooling/JSONCompilationDatabase.cpp
+++ b/clang/lib/Tooling/JSONCompilationDatabase.cpp
@@ -419,14 +419,13 @@ bool JSONCompilationDatabase::parse(std::string &ErrorMessage) {
     SmallString<128> NativeFilePath;
     if (llvm::sys::path::is_relative(FileName)) {
       SmallString<8> DirectoryStorage;
-      SmallString<128> AbsolutePath(
-          Directory->getValue(DirectoryStorage));
+      SmallString<128> AbsolutePath(Directory->getValue(DirectoryStorage));
       llvm::sys::path::append(AbsolutePath, FileName);
-      llvm::sys::path::remove_dots(AbsolutePath, /*remove_dot_dot=*/ true);
       llvm::sys::path::native(AbsolutePath, NativeFilePath);
     } else {
       llvm::sys::path::native(FileName, NativeFilePath);
     }
+    llvm::sys::path::remove_dots(NativeFilePath, /*remove_dot_dot=*/true);
     auto Cmd = CompileCommandRef(Directory, File, *Command, Output);
     IndexByFile[NativeFilePath].push_back(Cmd);
     AllCommands.push_back(Cmd);
diff --git a/clang/unittests/Tooling/CompilationDatabaseTest.cpp b/clang/unittests/Tooling/CompilationDatabaseTest.cpp
index 3314ecd..89763f9 100644
--- a/clang/unittests/Tooling/CompilationDatabaseTest.cpp
+++ b/clang/unittests/Tooling/CompilationDatabaseTest.cpp
@@ -92,16 +92,32 @@ TEST(JSONCompilationDatabase, GetAllFiles) {
   expected_files.push_back(std::string(PathStorage.str()));
   llvm::sys::path::native("//net/file1", PathStorage);
   expected_files.push_back(std::string(PathStorage.str()));
+  llvm::sys::path::native("//net/dir/file3", PathStorage);
+  expected_files.push_back(std::string(PathStorage.str()));
   EXPECT_EQ(expected_files,
-            getAllFiles("[{\"directory\":\"//net/dir\","
-                        "\"command\":\"command\","
-                        "\"file\":\"file1\"},"
-                        " {\"directory\":\"//net/dir\","
-                        "\"command\":\"command\","
-                        "\"file\":\"../file1\"},"
-                        " {\"directory\":\"//net/dir\","
-                        "\"command\":\"command\","
-                        "\"file\":\"file2\"}]",
+            getAllFiles(R"json(
+            [
+              {
+                "directory": "//net/dir",
+                "command": "command",
+                "file": "file1"
+              },
+              {
+                "directory": "//net/dir",
+                "command": "command",
+                "file": "../file1"
+              },
+              {
+                "directory": "//net/dir",
+                "command": "command",
+                "file": "file2"
+              },
+              {
+                "directory": "//net/dir",
+                "command": "command",
+                "file": "//net/dir/foo/../file3"
+              }
+            ])json",
                         ErrorMessage, JSONCommandLineSyntax::Gnu))
       << ErrorMessage;
 }