language server is too greedy searching for files

[daltairwalter]

Environment

Version: 1.105.1 (user setup)
Commit: 7d842fb85a0275a4a8e4d7e040d2625abbf7f084
Date: 2025-10-14T22:33:36.618Z
Electron: 37.6.0
ElectronBuildId: 12502201
Chromium: 138.0.7204.251
Node.js: 22.19.0
V8: 13.8.258.32-electron.0
OS: Windows_NT x64 10.0.26100

• C/C++ Extension Version: 1.28.3

Bug Summary and Steps to Reproduce

The C++ language server is scanning too many files and the directions in: https://github.com/microsoft/vscode-cpptools/wiki/Optimizing-your-configuration are not very effective because they focus on excluding paths rather than specifying the paths that I am interested in. This is like asking me to identify my team by finding all of the other teams and excluding each of them. The other options like reducing the folders with a multi-root workspace would be very difficult because there is a significant list of include paths. The browse.path seems like it may be useful, but the documentation is vague and indicates the the includePath will be used if unspecified, so it seems like this would already be used.

Are there any ways to directly indicate what should be scanned rather than what should not be scanned?

Configuration and Logs

"C_Cpp.autoAddFileAssociations": false,
        "C_Cpp.clang_format_style": "...",
        "C_Cpp.clang_format_sortIncludes": true,
        "C_Cpp.dimInactiveRegions": false,
        "C_Cpp.workspaceParsingPriority": "medium",
        "C_Cpp.default.intelliSenseMode": "msvc-x64",
        "C_Cpp.default.cStandard": "c11",
        "C_Cpp.default.cppStandard": "c++17",
        "C_Cpp.default.defines": [...],
        "C_Cpp.default.includePath": [...]

Other Extensions

No response

Additional context

No response

[sean-mcmanus]

@daltairwalter Yes, you can set the browse.path to include fewer directories than what would be used from the includePath if browse.path is not set. Does that work for you? For a multi-root workspace, the effective browse.path would be accumulated from all the workspace folders.

[daltairwalter]

It seems like it would be useful to scan everything in the includePath, but my includePath directories don't have anywhere near 700,000 files in them. I am not sure how changing this to a browse.path would help.

[daltairwalter]

setting browse path to empty seems to reduce the scanning, is there anything that needs the browse.path if the includePath is correct?

"C_Cpp.default.browse.path": []

[sean-mcmanus]

@daltairwalter Yes, the browse.path is required for global symbols, i.e. find workspace symbols (find all refs, go to def for a definition in a different TU), anything that needs to be stored in our database. You could add more paths to the browse.path for symbols you care about finding. The current TU (open source file and it's included headers using the includePath) is able to find all those symbols via IntelliSense. And if you open files those symbols will also get added to the database even if they're not part of the browse.path, but they may get removed after reloading the workspace.

[sean-mcmanus]

@daltairwalter Also, the browse.path is recursive by default and the includePath is not. You need to end a browse.path with /* if you want to make it non-recursive. If you're seeing 700,000 files being scanned when the includePath is used as the browse.path, it could be due to a recursive scan, potentially into a symlink.

[daltairwalter]

This explanation of browse.path and includePath is very helpful - thank you @sean-mcmanus.

With this understanding of browse.path and includePath, it seems like limiting the browse.path to my teams source and a few other related teams sources is sufficient, more helpful, and much smaller than the includes. I think having a clearer explanation of this in the documentation would be really helpful. Are there any other types of searches that are processed like browse.path and includePath, or these two it?

I tried a little digging with logging features, and it was not sufficiently easy to figure out where the 700,000 files that the language server is scanning were hiding. I looked for symlinks and the recursive sizes of all of the directories and I did not find anything that seemed like it would produce anywhere near this number. I think there is likely some type of bug here still and I would be happy to look again if more logging is added in the future that shows individual counts, but for my purposes setting browse.path is a better solution.

[sean-mcmanus]

Our existing docs on browse.path are at https://code.visualstudio.com/docs/cpp/customize-cpp-settings#_browse-properties .

What do you mean by "types of searches"? Only browse.path is used for "searching" for symbols if includePath is different, in which case the includePath is just used by IntelliSense for resolving #include references.

@daltairwalter If you temporarily set C_Cpp.loggingLevel to the hidden value of "8" you can see "update_file_if_needed" logging which shows which files are being searched through.