Add Trim Trailing Whitespace Preference

[colin-grant-work]

Signed-off-by: Colin Grant colin.grant@ericsson.com

What it does

Fixes #8059 by adding a preference an and onWillSaveModel hook to perform the action.

How to test

1. Add lots of trailing whitespace to a file.
2. Save it.
3. Observe that the whitespace is not removed.
4. Open preferences.
5. Set files.trimTrailingWhitespace to true in the scope of your white-spacey file (or higher scope).
6. Add even more whitespace.
7. Save the file.
8. Observe that the trailing whitespace is removed.

Since the preference name/description etc. are copied from VSCode, this is likely to require a CQ. I'll get started on that.

Review checklist

• [x ] as an author, I have thoroughly tested my changes and carefully followed the review guidelines

Reminder for reviewers

• as a reviewer, I agree to behave in accordance with the review guidelines

[kenneth-marut-work]

Functionality and code are working for me 👌 One issue I did notice is that there doesn't seem to be an implementation for 'language-overridable' scope in preference-scope.ts, so this preference (as well as file.encoding and files.autoGuessEncoding) do not show up inside Folder scope (which they do in VSCode). This maybe outside of the scope of this PR though

[vince-fugnitto]

@dukengn do you mind performing a review when you get a chance? I'll review as well.

[vince-fugnitto]

The changes work very well, I confirmed that a language-specific preference also works well.
I was a bit confused as to why JS/TS files do not respect the preference (they seem to be auto-formatted) but confirmed it is the same case in vscode.

[DucNgn]

The changes work well for me 👍 Can you please address Paul's comment?

[colin-grant-work]

I think I've created a CQ for copying the preference specification from VSCode here: https://dev.eclipse.org/ipzilla/show_bug.cgi?id=22866 🤞

[kittaakos]

It works as described, but every time I save, I see the following error in the console:

root ERROR onWillSave listeners should provide edits, not directly alter the document.

[vince-fugnitto]

It works as described, but every time I save, I see the following error in the console:

root ERROR onWillSave listeners should provide edits, not directly alter the document.

@kittaakos I remember that the issue is already present on master due to the editor.formatOnSave:

• [json] ERROR onWillSave listeners should provide edits, not directly alter the document when saving editor #6520 (comment)

The fix might be to eventually do as Anton suggested here: #6520 (comment).

[colin-grant-work]

The CQ has been triaged and this code may now be checked in.

[vince-fugnitto]

@colin-grant-work the changes work well 👍
In the future it may be something we want to try to cover in the saveable.spec.js api-tests along with formatOnSave.

[vince-fugnitto]

@colin-grant-work I believe the pull-request can be merged, thank you for the contribution :)