Clangd LSP set incorrect root and missing arguments

[wangzw]

Description

Currently clangd root directory is detected by NearestRoot(["compile_commands.json", "compile_flags.txt", ".clangd", "CMakeLists.txt", "Makefile"]), which is usually result in the up directory which contains "CMakeLists.txt" or "Makefile" of active file, and is not the root directory of project. Instead, clangd should run in the root directory.

clangd will search from active file directory up to root directory to find .clangd or compile_flags.txt. We do not need to do the search again in LSPServer.

compile_commands.json is important to clangd, clangd will look in the parent directories of active file looking for it, and also in subdirectories named "build/". But it usually fails if one build project out of source tree. Argument of clangd (--compile-commands-dir) can be used to pass the location.

So all we need to do:

1. set root directory of the project correctly.
2. pass compile_commands.json using argument.

Plugins

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OpenCode version

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Steps to reproduce

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Screenshot and/or share link

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Operating System

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Terminal

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[github-actions]

This issue might be a duplicate of existing issues. Please check:

• clangd LSP always fails #9521: clangd LSP always fails - reports bogus STL include errors when projects provide compile_commands.json via symlink
• [FEATURE]: LSP support for choosing between multiple build directories (c++ / clangd) #7780: [FEATURE]: LSP support for choosing between multiple build directories (c++ / clangd) - discusses the need to configure build directory for clangd, similar to passing compile_commands.json location

Feel free to ignore if none of these address your specific case.

[BLumia]

Not sure if you are using Windows, if so, you might need to ensure opencode is using the clangd that you expect it to use. For me OpenCode by default will attempt to download and use its own clangd but I need to make it use MSYS2's clangd, thus custom configuration needed. See #7405 (comment) for example configuration.

[wangzw]

Not sure if you are using Windows, if so, you might need to ensure opencode is using the clangd that you expect it to use. For me OpenCode by default will attempt to download and use its own clangd but I need to make it use MSYS2's clangd, thus custom configuration needed. See #7405 (comment) for example configuration.

I'm working MacOS and Linux. I have already submitted a patch (#11579), but the PR was ignored. So I gave up.

[nonbanana]

I agree with this issue. In most Make and CMake projects, Makefile and CMakeLists.txt do not indicate the project root — they exist in countless subdirectories throughout the tree.

llvm-project (https://github.com/llvm/llvm-project) is good example. llvm-project has CMakeLists.txt in every single subdirectory like clang/lib/Sema/, clang/lib/AST/, clang/lib/CodeGen/, etc. Opening any file there causes clangd to start in the wrong directory.
These markers should be removed from the clangd root detection. Only compile_commands.json, compile_flags.txt, and .clangd reliably indicate where clangd should run.