Formats on save even if excluded by `deno.json`

[felipecrs]

Describe the bug

The Deno extension for VS Code formats files on save even if they are excluded by deno.json.

To Reproduce

.vscode/settings.json:

{
  "[jsonc]": {
    "editor.defaultFormatter": "denoland.vscode-deno",
    "editor.formatOnSave": true
  }
}

deno.json:

{
  "fmt": {
    "exclude": [
      "fixture.jsonc"
    ]
  }
}

fixture.jsonc:

{"a": "property"} // should not be formatted

Gets formatted to:

{
    "a": "property"
} // should not be formatted

Expected behavior

Deno should not format files on save if excluded by deno.json. Similar to Deno CLI:

$ deno fmt fixture.jsonc
error: No target files found.

Screenshots

No response.

Versions

• vscode: 1.105.1
• deno: 2.5.4
• extension: 3.45.2

[ayonli]

This behavior is intended, since the formatter is integrated into VSCode's formatting functionality. The Deno extension does not control whether a document should or should not be formatted; VSCode itself does.

[felipecrs]

Just note that's now how the VS Code extension for Prettier works.

In that case, it honors the prettier ignore settings.

Deno could simply not format the file if it's in the ignore list, i.e. return early without modifying the file.

[ayonli]

But if the formatter respects the exclude configuration, when the user tries to format a document that is listed in the exclude list, for example, via the Format Document context menu item, the formatter will not work, and it would seem like VSCode is broken.

[felipecrs]

Yes, and that's exactly what happens with the Prettier VS Code.

In my opinion that's the correct behavior, because it's exactly what happens when invoked by CLI.

[ayonli]

The CLI is an individual program, but when integrated into VS Code, the formatter becomes part of the editor, and it should follow the editor's rules instead of on its own.

[felipecrs]

Your point makes sense from the Format Document command point of view. But my point was about format on save.

Do we agree it doesn't make sense that the Deno extension format files on save if they are listed in the Deno format ignore list?

Otherwise, the users need to keep toggling format on save on and off depending on whether they are working with ignored files or not, which I don't believe is ideal.

[ayonli]

After more thought, perhaps it'd be better if the exclude rule is respected. But instead of silently ignoring the formatting action, the extension should pop up a message that explains that the current file is excluded by the deno.json[c] configuration, and provide a setting to turn the warning on or off.

The Format on Save and Format Document are VSCode built-in functions and controlled by VSCode itself. The extension simply registers a formatting provider, so this is the best solution I can think.

[felipecrs]

I agree with the warning because it's indeed frustrating when calling the Format Document command and it doesn't do anything.

And it's too bad VS Code does not allow to differentiate between explicit formatting requests and implicit ones like on save.

You may be able to hook on onWillSaveTextDocument or maybe even on onDidExecuteCommand (editor.action.formatDocument) to detect whether the next formatting operation is explicit or not. But I also agree that's a bit hacky.