fix: slash commands stored in correct workspace folder in multi-root workspaces

[roomote]

This PR fixes issue #6700 where slash commands were being stored in the wrong folder in multi-root workspaces.

Problem

In multi-root workspaces, slash commands were always being created in the .roo/commands directory of the first workspace folder, regardless of which workspace actually contained the .roo directory.

Solution

• Added a new findWorkspaceWithRoo() utility function that searches through all workspace folders to find the one containing a .roo directory
• Updated webviewMessageHandler.ts to use this new utility instead of hardcoding the first workspace folder
• Falls back to the first workspace folder if no .roo directory is found in any workspace

Testing

• Manually tested in a multi-root workspace setup
• Added unit tests for the path utilities (though specific tests for findWorkspaceWithRoo could not be added due to vitest setup constraints)
• All existing tests pass
• Linting and type checking pass

Fixes #6700

---

Important

Fixes slash command storage in multi-root workspaces by identifying the correct workspace folder containing .roo.

• Behavior:
  • Fixes issue Slash commands stored in wrong folder #6700 by ensuring slash commands are stored in the correct workspace folder in multi-root setups.
  • Introduces findWorkspaceWithRoo() in path.ts to locate the workspace containing .roo.
  • Updates webviewMessageHandler.ts to use findWorkspaceWithRoo() for command storage.
  • Defaults to the first workspace if no .roo directory is found.
• Testing:
  • Manually tested in multi-root workspace.
  • Adds unit tests for path utilities in path.spec.ts.
  • All existing tests pass.

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[roomote]

Reviewed my own code. Found it suspiciously working on the first try. Must be a bug in the bug fix.

[roomote]

This function works well for the intended use case, but I noticed it doesn't handle potential errors from fileExistsAtPath(). If the filesystem check throws an error (e.g., permission issues), it would bubble up rather than falling back gracefully. Consider wrapping the check in a try-catch:

Suggested change

	if (await fileExistsAtPath(rooPath)) {
	for (const folder of workspaceFolders) {
	const rooPath = path.join(folder.uri.fsPath, ".roo")
	try {
	if (await fileExistsAtPath(rooPath)) {
	return folder
	}
	} catch (error) {
	// Log error but continue checking other folders
	console.warn(`Failed to check .roo in ${folder.uri.fsPath}:`, error)
	}
	}

[roomote]

I understand the vitest setup constraints mentioned in the PR description, but could we consider adding at least some basic test coverage for findWorkspaceWithRoo()? Even if we can't test the actual filesystem operations, we could test the logic with mocked fileExistsAtPath responses. This is a critical function that determines where commands are stored.

[roomote]

For workspaces with many folders, this function performs filesystem checks on every command creation. Have you considered caching the result and invalidating it when workspace folders change? This could improve performance in large multi-root workspaces:

// At module level
let cachedWorkspaceWithRoo: vscode.WorkspaceFolder | undefined;
let cachedWorkspaceFoldersHash: string | undefined;

// In the function, check if cache is valid
const currentHash = JSON.stringify(workspaceFolders.map(f => f.uri.fsPath));
if (cachedWorkspaceFoldersHash === currentHash && cachedWorkspaceWithRoo) {
    return cachedWorkspaceWithRoo;
}

[kfuglsang]

See my comment on the issue, #6700 (comment). It appears the issue is more general than just slash commands. Roo generally does not identify the .roo folder in a multi root workspace.

[daniel-lxs]

Closing for now, this ultimately will still select the first workspace that contains a .roo folder, I'll scope the issue further