Rubocop TIP output is going to files on auto save

After upgrading to 1.5.1, Rubocop by default prints the following message in the console when you run the command:

Tip: Based on detected gems, the following RuboCop extension libraries might be helpful:
  * rubocop-rails (http://github.com/rubocop-hq/rubocop-rails)
  * rubocop-rspec (http://github.com/rubocop-hq/rubocop-rspec)

You can opt out of this message by adding the following to your config (see https://docs.rubocop.org/rubocop/extensions.html#extension-suggestions for more options):
  AllCops:
    SuggestExtensions: false

This exact message appears at the end of every file when I save using the auto formatting in the VSCode Extension.

Versions

• Ruby 2.5.1p57 (2018-03-29 revision 63029)
• gem Rubocop: ~> 1.5.1
• VSCode

Version: 1.51.1
Commit: e5a624b788d92b8d34d1392e4c4d9789406efe8f
Date: 2020-11-10T23:31:29.624Z
Electron: 9.3.3
Chrome: 83.0.4103.122
Node.js: 12.14.1
V8: 8.3.110.13-electron.0
OS: Linux x64 4.15.0-118-generic

• ruby-rubocop: 0.8.5

Relevant VSCode preferences

{
    "ruby.format": "rubocop",
    "editor.formatOnSave": true,
    "editor.formatOnSaveTimeout": 5000,
    "[ruby]": {
        "editor.defaultFormatter": "misogi.ruby-rubocop"
    },
    "ruby.rubocop.useBundler": true,
}

Setting the option SuggestExtensions: false as showed by Rubocop fixes the issue; for now.

[cspotcode]

The bug here is that those messages should not be written into the .rb source file. The extension is writing them into the .rb source file, meaning that attempting to save an .rb file causes the editor to append invalid syntax, (those messages) breaking the file.

Diagnostic, warning, and error messages should be displayed in VSCode’s interface, not written into source code. If the existence of those messages makes it impossible to format a file, then the file should remain unmodified.

On Mon, Dec 21, 2020, 1:54 AM Daniel Vandersluis [e-mail] wrote:

@cspotcode https://github.com/cspotcode the message you’re getting is due to RuboCop marking new cops as pending between major releases. You can choose to automatically enable or disable them by default in your .rubocop.yml along with SuggestExtensions: false, which will continue to use the default rubocop configuration but remove the warning messages you’re experiencing):

AllCops: NewCops: [enable|disable] # choose one SuggestExtensions: false

See https://docs.rubocop.org/rubocop/1.6/versioning.html for more details.

— You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub https://github.com/misogi/vscode-ruby-rubocop/issues/138#issuecomment-748799337, or unsubscribe https://github.com/notifications/unsubscribe-auth/AAC35OHDJY6CM74RWQ7RFT3SV3WJPANCNFSM4UMRHOZQ .

[dvandersluis]

This is not a RuboCop bug, but rather a bug of how this library is calling RuboCop. The suggested extensions text only is added when using a formatter that is intended for human consumption. If this library used a RuboCop formatter meant for parsing (-f j for json for instance), the text would not be output by RuboCop and then added to your code.