Support configurable root directory for project absolute (//) paths

[magreenblatt]

I have a project that builds using a separate Git repository placed inside the chromium/src directory (e.g. placed at chromium/src/cef). This separate Git repository contains BUILD.gn files referencing files rooted in the Chromium src directory via absolute paths (like import("//base/allocator/allocator.gni")). However, because the cef directory is a separate Git repository the GN Language Server assumes that cef is the project root and "Follow link (ctrl + click)" in the VSCode editor does not resolve correctly (e.g. assumes absolute paths are relative to chromium/src/cef instead of chromium/src as desired). Please add an option to configure the project absolute root directory for Follow link purposes. Thanks.

[Qusic]

currently the project root is determined by looking for the file .gn

gnls/addon/addon.cc

Lines 284 to 299 in 1169ebd

	auto FindRoot() -> base::FilePath {
	base::FilePath current =
	UTF8ToFilePath(file_.dir().SourceWithNoTrailingSlash());
	for (;;) {
	base::FilePath file = current.Append(FILE_PATH_LITERAL(".gn"));
	if (base::PathExists(file)) {
	return current;
	}
	base::FilePath upper = current.StripTrailingSeparators().DirName();
	if (current == upper) {
	break;
	}
	current = std::move(upper);
	}
	return {};
	}

are you also using gn command line args like --root or --dotfile to override the default behavior? https://gn.googlesource.com/gn/+/main/docs/reference.md#dotfile

[magreenblatt]

Thanks for the details!

currently the project root is determined by looking for the file .gn

That may not be the best approach for Chromium, as (for example) the chromium/src/v8 directory is a separate repository that contains a .gn file. Consequently, absolute paths in v8/BUILD.gn do not work with "Follow link (ctrl + click)" either when loading chromium/src as the VSCode workspace.

are you also using gn command line args like --root or --dotfile to override the default behavior?

No, I'm using a default Chromium checkout with an additional chromium/src/cef directory (contents here), and the chromium/src/BUILD.gn file modified to include the //cef target. The cef directory does not contain a .gn file, so I'm unsure why this is a problem for me. I'll try to debug the extension code to see if I can figure out what's going in.

[magreenblatt]

I'll try to debug the extension code to see if I can figure out what's going in.

Looks like I was too optimistic 😅. How would I go about debugging a language server extension installed in my existing VSCode workspace? Is it possible to build/install a debug version of this extension? Thanks.

[Qusic]

https://github.com/microsoft/gnls/blob/main/CONTRIBUTING.md#build-and-run

please check this out. basically we have some predefined tasks/configs that can be used out of box (hopefully still working after this long time 🫠)

[magreenblatt]

Thanks for the link. The npm install command doesn't appear to work with my current Node.js version (v14.18.0) on MacOS ARM. I have Python, Xcode (+Command Line Tools), Ninja and node-gyp installed. Is there a particular Node.js version that I should install, or other prerequisites that I should be aware of?

% npm install  
npm WARN deprecated eslint@8.57.1: This version is no longer supported. Please see https://eslint.org/version-support for other options.
npm WARN deprecated glob@7.2.3: Glob versions prior to v9 are no longer supported
npm WARN deprecated glob@8.1.0: Glob versions prior to v9 are no longer supported
npm WARN deprecated @humanwhocodes/config-array@0.13.0: Use @eslint/config-array instead
npm WARN deprecated inflight@1.0.6: This module is not supported, and leaks memory. Do not use it. Check out lru-cache if you want a good and tested way to coalesce async requests by a key value, which is much more comprehensive and powerful.
npm WARN deprecated @humanwhocodes/object-schema@2.0.3: Use @eslint/object-schema instead
npm WARN deprecated rimraf@3.0.2: Rimraf versions prior to v4 are no longer supported

> keytar@7.9.0 install /Users/marshall/code/gnls/node_modules/keytar
> prebuild-install || npm run build


> @vscode/vsce-sign@2.0.5 postinstall /Users/marshall/code/gnls/node_modules/@vscode/vsce-sign
> node ./src/postinstall.js


> gnls@0.1.4 prepare /Users/marshall/code/gnls
> ts-node script prepare

HEAD is now at e4702d74 Optimize base::EscapeJSONString for ASCII inputs.
HEAD is now at e4702d74 Optimize base::EscapeJSONString for ASCII inputs.
Error: ENOENT: no such file or directory, copyfile 'build/Debug/compile_commands.json' -> 'compile_commands.json'
    at Object.copyFileSync (fs.js:2061:3)
    at copy (/Users/marshall/code/gnls/script/index.ts:45:6)
    at compdb (/Users/marshall/code/gnls/script/index.ts:122:3)
    at run (/Users/marshall/code/gnls/script/index.ts:149:7)
    at Object.<anonymous> (/Users/marshall/code/gnls/script/index.ts:191:1)
    at Module._compile (internal/modules/cjs/loader.js:1085:14)
    at Module.m._compile (/Users/marshall/code/gnls/node_modules/ts-node/src/index.ts:1618:23)
    at Module._extensions..js (internal/modules/cjs/loader.js:1114:10)
    at Object.require.extensions.<computed> [as .ts] (/Users/marshall/code/gnls/node_modules/ts-node/src/index.ts:1621:12)
    at Module.load (internal/modules/cjs/loader.js:950:32) {
  errno: -2,
  syscall: 'copyfile',
  code: 'ENOENT',
  path: 'build/Debug/compile_commands.json',
  dest: 'compile_commands.json'
}
npm ERR! code ELIFECYCLE
npm ERR! errno 1
npm ERR! gnls@0.1.4 prepare: `ts-node script prepare`
npm ERR! Exit status 1
npm ERR! 
npm ERR! Failed at the gnls@0.1.4 prepare script.
npm ERR! This is probably not a problem with npm. There is likely additional logging output above.

npm ERR! A complete log of this run can be found in:
npm ERR!     /Users/marshall/.npm/_logs/2025-03-27T17_14_25_238Z-debug.log

[Qusic]

oh it should be pnpm. i forgot to update the doc
and v14 is too old, i guess.

btw you can try this branch, i am trying to upgrade some deprecated dependencies. it works for me but the CI is still failing
#49

[magreenblatt]

Thanks! After installing node 23.10.0 and updating to your PR (now merged), the pnpm install command works for me. However, the pnpm run build command fails with:

% pnpm run build

> gnls@0.1.4 build /Users/marshall/code/gnls
> jiti script build


src/index.ts, src/server.ts → build...
(!) Circular dependency
node_modules/.pnpm/semver@7.7.1/node_modules/semver/classes/range.js -> node_modules/.pnpm/semver@7.7.1/node_modules/semver/classes/comparator.js -> node_modules/.pnpm/semver@7.7.1/node_modules/semver/classes/range.js
created build in 2.4s
Failed to execute: python build/gen.py --out-path out/x64 (spawnSync python ENOENT)
 ELIFECYCLE  Command failed with exit code 255.

In case this is an issue pnpm itself, I installed it with:

npm install -g pnpm@latest-10

[magreenblatt]

Failed to execute: python build/gen.py --out-path out/x64 (spawnSync python ENOENT)

Switched to python3 in index.ts, now the pnpm run build step is proceeding.

[magreenblatt]

Using DebugExtension and AttachNode configurations I'm able to set and hit breakpoints in addon.cc.

FindRoot() appears to be working correctly when processing the import() link that was clicked (e.g. import("//base/allocator/allocator.gni") has root src/base).

Now I'm attempting to find the code that builds the path that the editor will open (e.g. when the import() is from src/cef/BUILD.gn it attempts to open src/cef/base/allocator/allocator.gni, which is incorrect).

[magreenblatt]

Using the AttachServer configuration I can see that filepath is correct in server.ts getDefinition targetUri.

[magreenblatt]

I'm not having much luck finding where/how VSCode determines the path to actually open. Any suggestions on where to debug further are welcome.

[Qusic]

like the code link you shared, it's just appending path in that string to root path from the native addon. a new GNDocument object will be created for every opening file in vscode (a root will be determined for each file too, by looking for .gn from that directory). in other words, this extension is not aware of the workspace directory in vscode. 🤔

[magreenblatt]

a new GNDocument object will be created for every opening file in vscode

Does this occur before or after VSCode opens the new file? If it occurs after, do you know what code opens the new file (determines the path to open) in VSCode?

in other words, this extension is not aware of the workspace directory in vscode

Right, I suspect that the issue is with the code that opens the new file (determines the path to open) in VSCode, and possibly not with the gnls extension directly.

[Qusic]

nothing is done if no gn files are opened. when using goto to open another file, this extension gives vscode the full path so there shouldn't be any ambiguity.

here is the call to native addon when a file is opened or changed
gn.update is implemented here
and here is a map of file path to GNDocument objects