Support `userHome` and other env variables in settings

[nickeldan]

Type: Bug

The extension cannot resolve the path to my Python interpreter (which I've confirmed exists). In my workspace's settings.json file, I have

"python.defaultInterpreterPath": "${userHome}/path/to/python3"

However, Python's output shows

[error] Error initializing python: [l [Error]: Failed to resolve env "/path/to/project/${userHome}/path/to/python3"

Extension version: 2024.22.1
VS Code version: Code 1.96.2 (Universal) (fabdb6a30b49f79a7aba0f2ad9df9b399473380f, 2024-12-19T10:22:47.216Z)
OS version: Darwin x64 24.2.0
Modes:
Remote OS version: Linux x64 6.8.0-51-generic

A/B Experiments

vsliv368:30146709
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azure-dev_surveyone:30548225
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cppperfnew:31000557
dsvsc020:30976470
pythonait:31006305
dsvsc021:30996838
dvdeprecation:31068756
dwnewjupyter:31046869
nativerepl2:31139839
pythonrstrctxt:31112756
nativeloc1:31192215
cf971741:31144450
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notype1:31157159
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dwcopilot:31170013
stablechunks:31184530
6074i472:31201624

[karthiknadig]

userHome is environment variable and is not supported in this scenario. Note that VS Code itself does not support these variables in settings, it is only supported in launch.json, and tasks.json.

Python extension handles env variables in some cases like in .env files. There are also system variables, like workspace folder, selected file, selected text etc, those are also handled in some cases not all.

vscode-python/src/client/common/variables/systemVariables.ts

Lines 143 to 201 in 74a5cad

	public get cwd(): string {
	return this.workspaceFolder;
	}
	public get workspaceRoot(): string {
	return this._workspaceFolder;
	}
	public get workspaceFolder(): string {
	return this._workspaceFolder;
	}
	public get workspaceRootFolderName(): string {
	return this._workspaceFolderName;
	}
	public get workspaceFolderBasename(): string {
	return this._workspaceFolderName;
	}
	public get file(): string | undefined {
	return this._filePath;
	}
	public get relativeFile(): string | undefined {
	return this.file ? Path.relative(this._workspaceFolder, this.file) : undefined;
	}
	public get relativeFileDirname(): string | undefined {
	return this.relativeFile ? Path.dirname(this.relativeFile) : undefined;
	}
	public get fileBasename(): string | undefined {
	return this.file ? Path.basename(this.file) : undefined;
	}
	public get fileBasenameNoExtension(): string | undefined {
	return this.file ? Path.parse(this.file).name : undefined;
	}
	public get fileDirname(): string | undefined {
	return this.file ? Path.dirname(this.file) : undefined;
	}
	public get fileExtname(): string | undefined {
	return this.file ? Path.extname(this.file) : undefined;
	}
	public get lineNumber(): number | undefined {
	return this._lineNumber;
	}
	public get selectedText(): string | undefined {
	return this._selectedText;
	}
	public get execPath(): string {
	return this._execPath;
	}

[github-actions]

Thanks for the feature request! We are going to give the community 60 days from when this issue was created to provide 7 👍 upvotes on the opening comment to gauge general interest in this idea. If there's enough upvotes then we will consider this feature request in our future planning. If there's unfortunately not enough upvotes then we will close this issue.