Formatter removes final newline on package.json

[tsmaeder]

Bug Description:

The Theia workspace contains a setting to turn on "format on save" for the workspace. This is problematic, since the formatter does not work as intended: if I edit a package.json file, the formatter will remove the final newline. This leads to problems on UNIX-derived platforms.

Steps to Reproduce:

1. Edit a package.json in the Theia source
2. Save
3. Observe: the formatter removes the final newline.

Additional Information

• Operating System: Windows
• Theia Version: 1.47.0

[tsmaeder]

In current version of VS Code, there seems to be a setting files.insertFinalNewline, but that setting does not show up yet in 1.47.100 of Theia IDE. Not sure if we're just missing a monaco update here 🤷

[xai]

I cannot reproduce this on current master.

[tsmaeder]

@xai are you using the a Theia workspace to test? "Format on save" is turned on in the workspace settings. I just observed this again in the Theia IDE 1.47.100.

[xai]

I can reproduce this now (with Theia IDE 1.49.101).

[xai]

Unfortunately, Monaco Editor has no such thing as editor.action.insertFinalNewline that we could call.

I opened a draft PR with a workaround to support the files.insertFinalNewline setting.
Also, I feel my current workaround (i.e., the protected function) is somehow in the wrong place. Any suggestions on where it would fit better?

[tsmaeder]

Do we understand why the formatter removes the final newline? As far as I can tell, this does not happen in VS Code.

[xai]

Do we understand why the formatter removes the final newline? As far as I can tell, this does not happen in VS Code.

I think it does, see attached screencast.

vscode-finalnewline.mp4

[tsmaeder]

I'm sorry, but what am I seeing?

[xai]

I'm sorry, but what am I seeing?

This is vscode (cleaned user data) with a workspace that has formatOnSave enabled (see right pane).

Initially, insertFinalNewline is not set (right pane).
On the first save action, the empty line at the end of the package.json in the left pane is removed automatically (i.e., line 46 is deleted in the package.json).

Then, I enabled the insertFinalNewline setting in the right pane and repeated the experiment with the package.json. The second save does not remove the empty line, i.e. line 46 remains.

[JonasHelming]

@tsmaeder

[tsmaeder]

@xai What's the reason the PR is in draft state?

[xai]

@xai What's the reason the PR is in draft state?

Also, I feel my current workaround (i.e., the protected function) is somehow in the wrong place. Any suggestions on where it would fit better?

This concern of mine was the reason I kept it in draft state.