Test: new default file watcher

[bpasero]

Refs: #132483

• macOS @TylerLeonhardt
• linux @lramos15
• windows @joaomoreno

Complexity: 5

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The file watcher (vscode-nsfw) that was previously only used in multi-root workspaces is now enabled by default on all platforms even when opening a single folder. On top of that, the watcher service that leveraged it in VSCode was rewritten.

Setup: best to test this on a larger code base (like VSCode itself) and doing changes not only in root but also in deep hierarchies. In order to diagnose issues you can:

• run code-insiders --verbose
• filter the Console by putting nsfw into the filter
• monitor the output: you will see every raw file event reported from the nsfw library and a normalised event signalling the event that is actually being sent to VSCode

IMPORTANT: over the years we have built a lot of measures to workaround missing file events making it actually a bit harder to test the functionality of these events. As such:

• never do a file modification in the same VSCode window that you observe because when e.g. deleting a file using VSCode explorer, we remove it instantly knowing that it was deleted
• even when you do a change outside of the VSCode window, make sure to observe the change in the window without moving focus into the window - we refresh the explorer and opened editors when that happens assuming there was a change

Testing Events

• basic operations are reflected in the VSCode explorer when done from a VSCode explorer in another window
  • file/folder create
  • file/folder delete
  • file/folder move
  • file/folder rename
  • file/folder copy
• the same is true when doing these operations from the native OS explorer (e.g. Windows explorer, macOS Finder)
• changes to files are reflected in the editor if the file is opened in the editor

Testing Robustness

• even under large pressure the watching never stops working (e.g. large npm install or git operation) - monitor devtools output for information in case it stops working
• macOS/Linux: delete the folder that you opened as workspace and bring it back and verify the file watcher continues to work without window reload
• Linux: configure a low fs.inotify.max_user_watches (instructions), restart and open a large folder with VSCode and verify you see a warning notification telling you how to increase that limit

Testing New Settings

• ensure you have a folder in your workspace that is a symbolic link to a folder outside the workspace and use the new files.watcherInclude setting to enable it for watching and verify that works
• ensure you can force to use our old watcher when configuring files.legacyWatcher. if you run with --verbose and search for "watcher", the name of the watcher will be printed (chokidar for macOS, Linux and C# for Windows)

[TylerLeonhardt]

ensure you can force to use our old watcher when configuring files.legacyWatcher. if you run with --verbose and search for "watcher", the name of the watcher will be printed (chokidar for macOS, Linux and C# for Windows)

I only see [File Watcher (node.js)] does that imply chokidar? It does say [File Watcher (nsfw)] before the change.

[TylerLeonhardt]

ensure you have a folder in your workspace that is a symbolic link to a folder outside the workspace and use the new files.watcherInclude setting to enable it for watching and verify that works

So does this mean I could add a ton of paths to this setting that are not opened in VS Code and nsfw will still watch them regardless? Could I add / as a path in my workspace settings and slow down the user's machine?

[bpasero]

@TylerLeonhardt you should see [File Watcher (chokidar)] but I forgot to mention that for the file watcher to be used, you need to open a folder or multi-root workspace and not be in an empty window with loose files. And even when you are in a folder or workspace: any file that is outside of that workspace is watched by a custom node.js based watcher that is only watching that particular file. So maybe that happened here? You can try again by opening a folder and observing files of that folder?

So does this mean I could add a ton of paths to this setting that are not opened in VS Code and nsfw will still watch them regardless? Could I add / as a path in my workspace settings and slow down the user's machine?

No, we only allow paths that are inside the workspace:

vscode/src/vs/workbench/contrib/files/browser/workspaceWatcher.ts

Lines 132 to 144 in 24b3b58

	// Absolute: verify a child of the workspace
	if (isAbsolute(includePath)) {
	const candidate = URI.file(includePath).with({ scheme: workspace.uri.scheme });
	if (isEqualOrParent(candidate, workspace.uri)) {
	pathsToWatch.set(candidate, candidate);
	}
	}
	// Relative: join against workspace folder
	else {
	const candidate = workspace.toResource(includePath);
	pathsToWatch.set(candidate, candidate);
	}