[CP] Fix missing closure code completion entries for function parameters

[DanTup]

Commit(s) to merge

28d9ac0

Target

stable

Prepared changelist for beta/stable

https://dart-review.googlesource.com/c/sdk/+/337341

Issue Description

In the latest SDK release, completions for functions/closures are missing for LSP/VS Code:

Flutter 3.13

Flutter 3.16

This was a bug introduced in eb73dba that resulted in them not having the correct labels set and being filtered out by the client.

What is the fix

The fix is to ensure the labels for closure completions are not accidentally replaced by empty strings when cleaning up label/filterText in LSP (something done to improve the display of function names, parameters, signatures in code completion).

This is a simple change to not split completion labels (to remove parameters/etc.) if the split character is at the start of the string (this means foo() would be split to keep only foo, but () => would not result in an empty string).

Why cherry-pick

Although this is just completion and users can certainly type the function signature themselves, this feels like a significant usability regression - you'd have to hover over the parameter name to see the signature and the hover may obscure where you're typing.

This issue is being reported a lot (despite a pinned issue) 😔

• Completion does not suggest function structure Flutter 3.16 Dart-Code/Dart-Code#4845
• In the new version vscode auto complete stopped working Dart-Code/Dart-Code#4846
• VS code auto completion for function not working Dart-Code/Dart-Code#4848
• flutter suggestion problem Dart-Code/Dart-Code#4850
• Function Snippet Dart-Code/Dart-Code#4854

It may have been reported more, but I pinned my original issue about it to try and avoid duplicates.

Risk

low

Issue link(s)

Dart-Code/Dart-Code#4837

Extra Info

(FYI @jacob314 @bwilkerson)

[athomas]

Risk looks small, has a test. +1

[athomas]

Released in 3.2.2.