[lsp] - rename symbol keeping the same name

[ericdallo]

It seems that dart_analysis_server crashes when receive a textDocument/rename with the same symbol name on the newName field.

I could not reproduce it on VSCode because vscode seems to not send the textDocument/rename when the symbol name is the name, but on Emacs using lsp-dart, we send the textDocument/rename and after the server returns null on the response(Which is ok following the LSP spec), the dart_analysis_server process crash.

Some log from the lsp-dart client:

[Trace - 04:36:07 PM] Sending request 'textDocument/prepareRename - (183)'.
Params: {
  "textDocument": {
    "uri": "file:///home/greg/dev/flutter_sample/lib/screens/dashboard/components/rightscreen.dart"
  },
  "position": {
    "line": 52,
    "character": 21
  }
}

[Trace - 04:36:07 PM] Received response 'textDocument/prepareRename - (183)' in 8ms.
Result: {
  "placeholder": "_goToNextPage",
  "range": {
    "end": {
      "character": 28,
      "line": 52
    },
    "start": {
      "character": 15,
      "line": 52
    }
  }
}

[Trace - 04:36:12 PM] Sending request 'textDocument/rename - (184)'.
Params: {
  "textDocument": {
    "uri": "file:///home/greg/dev/flutter_sample/lib/screens/dashboard/components/rightscreen.dart"
  },
  "position": {
    "line": 52,
    "character": 21
  },
  "newName": "_goToNextPage"
}

[Trace - 04:36:12 PM] Received response 'textDocument/rename - (184)' in 7ms.
Result: null

Tested on flutter channel stable, dart 2.8.1 and flutter dev channel, Dart 2.9.0 (build 2.9.0-19.0.dev 7e72c9ae7e)

[ericdallo]

emacs-lsp/lsp-dart#41

[bwilkerson]

@scheglov @DanTup

[DanTup]

I get a different response from the server than in the log above (an error instead of null):

Content-Length: 114
Content-Type: application/vscode-jsonrpc; charset=utf-8
{"id":7,"jsonrpc":"2.0","error":{"code":-32010,"message":"The new name must be different than the current name."}}

However, the server still stopped responding (even in a test). It turned out to be a silly mistake - I had reused an error code, and it happened to the the one raised then the client/server are out-of-sync which results in a server shutdown 😞

I've got a fix here: https://dart-review.googlesource.com/c/sdk/+/153341/

[ericdallo]

I see, thank you for the quick fix @DanTup, I'll keep an eye on that :)

[DanTup]

This was fixed by 34ad5a5.

(@bwilkerson @ericdallo I don't have powers to close this, so someone will have to do it for me. Thanks!)

[ericdallo]

Thank you very much @DanTup :)