Go to Symbol in Workspace... breaks if custom file system provider folders exist in workspace #4107

Environment data

• VS Code version: 1.30.2
• Extension version (available under the Extensions sidebar): 2018.12.1
• OS and version: Windows 10
• Python version (& distribution if applicable, e.g. Anaconda): 3.6.8, Anaconda
• Type of virtual environment used (N/A | venv | virtualenv | conda | ...): conda
• Relevant/affected Python packages and their versions: N/A

Expected behaviour

When using Go To Symbol in Workspace... I should get a list populated with symbols in the workspace, at least for the directories which are not virtual.

Actual behaviour

An error is thrown when trying to process virtual directories, resulting in the popup prompting the user to install ctags (even though it is installed) being fired.

Steps to reproduce:

1. Use some method to add a virtual directory to your workspace. I used GitLens and "Explore Repository from Here" on a branch, which gives be a virtual directory representing the repository's state in that branch.
2. Try "Go to Symbol in Workspace..."

Logs

Output for Python in the Output panel (View→Output, change the drop-down the upper-right of the Output panel to Python)

I fixed this locally, so I can't post logs without undoing my fix which is cumbersome.

Output from Console under the Developer Tools panel (toggle Developer Tools on under Help; turn on source maps to make any tracebacks be useful by running Enable source map support for extension debugging)

Ditto.

Fix

To fix this issue locally, I edited the extension.js file replacing
get enabled(){return this.pythonSettings.workspaceSymbols.enabled}
with
get enabled(){return this.pythonSettings.workspaceSymbols.enabled&&this.workspaceFolder.scheme === "file"}

Refer to this line of the actual TypeScript source of the extension for where I placed the check, essentially disabling generators if the related folder does not have the file scheme for the uri. This might not be the best approach, but it was easiest to hack into extension.js.

The idea of the approach should work though, don't try to generate symbols for virtual directories.