VScode clangd failed to find my header file not found `clang(pp_file_not_found)`

Description:

I'm using clangd as my language server for coding c/c++ with CMake in vscode.

However, I'm experiencing some annoying bugs that keep interrupting me.

forehead/include.h' file not found clang(pp_file_not_found)

Bugs Reproduction:

I got a directory called include which looks like this:

.
├── CMakeLists.txt
├── forehead
│   └── include.h
├── graph
│   └── graph.h
├── list
│   ├── linklist.h
...

In linklist.h, clangd works fine with no errors or warnings, and I can jump to file include.h with gd:

#include <forehead/include.h>

But the exactly same line in graph.h, clangd keeps give me the error:forehead/include.h' file not found clang(pp_file_not_found), preventing me from jumping to that file, every keyword or function from include.h are treated as errors by clangd.

Environment:

• OS: macOS ventura 13.0
• clangd: 16.0.3
• CMake: 3.26.3

root/CMakeLists.txt:

set(CMAKE_EXPORT_COMPILE_COMMANDS ON)

vscode/setting.json:

  "clangd.path": "/opt/homebrew/opt/llvm/bin/clangd",
  "clangd.arguments": ["--header-insertion=never"],
  "clangd.serverCompletionRanking": true,

Expectation:

It is worth mentioning that I can navigate within Vim and successfully build the .o and executable files using CMake.

I'm tired of dealing with this annoying bug that keeps popping up every time I write a new header file.

(BTW: The bug may disappear for no apparent reason, perhaps the next time I open VSCode -- However, deliberately restarting the clangd or reloading the VSCode window does not seem to be effective.

Clangd works by partially compiling your file and parsing the AST. For source files (.cpp/.c/etc.) it just compiles that file directly, which should be fine.

For header files, it can't compile them directly, so it seems the current approach is to pick a source file that should match your header file. The problem is that this is based on heuristics and frequently fails, finding nonsense files inside your dependencies or elsewhere (see https://github.com/clangd/clangd/issues/519 or https://github.com/clangd/clangd/issues/123).

If this is your issue, you can diagnose it by opening the "clangd" language server output on VSCode, and looking for a line like this:

ASTWorker building file e:\your\folder\forehead\include.h version 1 with command inferred from E:\somewhere\else\Include.cpp

This is very annoying and I don't think there's a clean way around it.. except maybe renaming your file and some matching .cpp file to something more distinctive, like forehead_include.h and having a relevant forehead.cpp next to it? Otherwise a name like include.h may be paired with random files somewhere else.

Edit: I have also had some partial success trying to include with quotes and relative paths, like #include "../forehead/include.h"