file.watcherExclude preference doesn't prevent watcher from being created

[kenneth-marut-work]

Bug Description:

Following the trail of options.exclude from the FileService's watch method doesn't seem to actually prevent a watcher from being created. It instead prevents a change event from being pushed into the event that is emitted from nsfw-filesystem-service (see pushFileChange method). This results in inotify resources still being consumed for no reason (correct me if I'm wrong).

In our downstream IDE, our users import large repositories (only for search/readonly purposes) in parallel with their working directories. These large repositories eat up file watcher resources even though they won't expect to see any changes. This can cause the UI to break and other files to not respond to changes (such as branch changes etc.). Experimenting with the exclude preference seems to have no affect.

Steps to Reproduce:

Using the script below to observe inotify consumers found here

curl -s https://raw.githubusercontent.com/fatso83/dotfiles/master/utils/scripts/inotify-consumers | bash

1. Open Theia with a multiroot workspace with RootA and RootB
2. Run the script and observe that X number of watchers are used by Theia (run it several times to make sure the number has reached steady state)
3. Add RootA to files.watcherExclude and run the script again (reaching steady state as they watchers re count after the change)
4. Observe the same number of file watchers are still being consumed

Additional Information

• Operating System: Linux
• Theia Version: master

[paul-marechal]

There is a fix for that on Linux in the following PR: Axosoft/nsfw#124

The PR is stalled because I wasn't able to figure out what to do with Windows. Help is welcome...

[paul-marechal]

On the other hand VS Code seem to have moved from nsfw and chokidar to https://github.com/parcel-bundler/watcher.