Hello GNU Emacs folks!

I’ve recently noticed lots of error messages printed by Eglot when
working on a Swift project:

  Error running timer: (error "Keyword argument :logName not one of
  (:type :message)") [2 times]

After digging a little bit, I found out that SourceKit-LSP is now
sending window/logMessage messages with a ‘logName’ field set [0], which
is not defined in the LSP specification [1].

Since Eglot isn’t doing anything particular with those messages, I think
it would be reasonable to allow other keys in that message.

Here’s how to reproduce the issue:
  1. Install swift-mode.
  2. Configure Eglot to support SourceKit-LSP:
       (use-package eglot
         :config (add-to-list 'eglot-server-programs
                              '(swift-mode . ("sourcekit-lsp")))  
         :defer t)
  3. Create an empty Swift 6.1 project:
     - mkdir /tmp/EglotTest; cd /tmp/EglotTest
     - swift package init
  4. Open the Package.swift file, enable Eglot, and take a look at the
     messages buffer.

I’m attaching a patch that fixes the issue. Let me know what you think!


Thanks,
-- gregoire

[0]: https://github.com/swiftlang/sourcekit-lsp/blob/12dc0483e32378a2f3c5afcc8337bd977644f182/Sources/LanguageServerProtocol/Notifications/LogMessageNotification.swift#L27-L37
[1]: https://microsoft.github.io/language-server-protocol/specifications/lsp/3.17/specification/#window_logMessage