"Format on Paste" & "Format on Save Mode: Modification" Deletes Lines Incorrectly

[andrewaustin]

VS Code version

1.87.2

Extension version

2.2.2

Biome version

1.6.1

Operating system

• Windows
• macOS
• Linux

Description

Spent a lot of time trying to track this down on discord, and was finally able to figure it out with the help of @Sec-ant

If your vscode settings are format on paste or are format mode: modification it seems that weird things happen. I assume this is because only small code fragments are being sent to biome instead of the full file, which biome does not support. See the repo case below.

To fix my issues I had to turn off both Format on Paste and the Format Save Mode to file

Steps to reproduce

This small snippet was enough to cause problems for me:

// let us set an empty customer
if (userJson.customer != undefined && userJson.customer !== null) {
  fakeItem.stripe_customer = { S: userJson.customer };
}

To recreate it you can just enable format on paste and then copy paste the comment let us set an empty customer and you'll see the if block deleted. If you want to test the format on modification mode, you can correct the biome issue (!= should be !==) and you'll also see the if block get deleted.

Expected behavior

Would expect the correct formatting.

Does this issue occur when using the CLI directly?

Not sure / Not applicable

Logs

No response

[nhedger]

This is most likely an LSP issue; I'm moving this issue to the main repo.

[ematipico]

which biome does not support.

It does support it. The heuristic to deduce a valid node might be flawed in this case, but it is supported.

Can you explain what format mode: modification does? We don't usually recommend this kind of setting.

See the repo case below.

Did you mean reproduction or repository?

Would expect the correct formatting.

Which is? What kind of formatting would you expect in this particular case?

Also, can you provide us with the trace logs coming from the extension?

Also, could run biome rage --daemon-logs provide us only the logs emitted during the paste action?

[Sec-ant]

I'd like to add a bit more backaground to clear things out. OP and I were chatting in the discord server and I'm able to reproduce this issue. Here is a video demo when editor.formatOnPaste is enabled:

format.on.paste.mp4

What kind of formatting would you expect in this particular case?

The expected behavior is that no extra lines should be deleted.

I haven't look into this issue yet but I agree providing daemon logs and biome trace output emitted during the paste action would be helpful for people who may be interested in solving this issue. ❤️

[ghiscoding]

probably related to the issue #1890 that I've opened couple weeks ago (which in my case was related to "Format on Save: modification" and after I've switched to the entire "file" save then the issue went away).

[sylvainpolletvillard]

I got the same issue and can confirm i fixed it by changing the format on save setting to "file"

[kenn]

Do we have a link to the upstream LSP bug so that we can track progress?