Format on Save

[jrieken]

Given the infrastructure we have built for #239 we can offer something like files.formatOnSave whichs mean format a document whenever we are about to save it.

[jrieken]

cc @ramya-rao-a , @mattetti, @lukehoban I see that vscode-go has this which won't be needed much longer. With #239 we will add the onWillSaveTextDocument event and with this isse we will utilise our new infrastructure to format on save.

I wanna poke your brains wrt to format on save and auto save. This is obviously a hot topic because auto-save happens while typing meaning formatting might kick in unpleasantly. Did you get feedback in that direction? Do you have ideas - like not formatting when it's auto-save and messing for your cursors?

[jrieken]

re #12449 (comment)

@HookyQR same question. How do people react to auto-save and format on save?

[jrieken]

Proposal is to ignore formatting when auto-save happens in an focused editor and when the edits overlap with any of the cursors - https://github.com/Microsoft/vscode/blob/joh/formatOnSave/src/vs/workbench/api/node/mainThreadSaveParticipant.ts#L124

[ramya-rao-a]

@jrieken Below is an excerpt from the README for the Go extension

If you do turn Auto Save on, you may also want to turn format-on-save off ("go.formatOnSave": "false"), so that it is not triggered while typing

It is suggested to not use both together.

There have been a few instances (microsoft/vscode-go#368, microsoft/vscode-go#447) which left users baffled when their code kept disappearing which was Auto Save triggering formatting that deleted unused imports or multiple new lines.
Long time users of the extension do not use this combination due to the exact same issue.

Since files.autosave is off by default, it was safe for go.formatOnSave to be on by default as per microsoft/vscode-go#253. The same issue has some feedback about this combination of settings.

[ramya-rao-a]

@jrieken Would the new files.formatOnSave format all files during Save All ? There is a feature ask for the same in Go extension microsoft/vscode-go#279

[jrieken]

re #12449 (comment) - yes formatOnSave will work together with Save All

[jrieken]

re #12449 (comment) - we now don't format on auto save