Allow debug adapters prioritize suggestions via breaking alphabetic sorting

[pavelfeldman]

Suggestions returned by the debug adapter are currently sorted by label then by type. This prevents debug adapters from suggesting their own completion order. For example, for JavaScript objects, useless __defineGetter__ suggestions are shown at the very top:

Begin able to control the order allows adapters listing properties as they wish, for example by prototype, hence pushing the object's properties to the very bottom.

[pavelfeldman]

I experimented with addressing it and the simplest way I found was prepending zero-width space to the suggestions in order to push them lower the stack. VS Code shows these suggestions, but does not quite like applying them out of the box. With a single line change to isWhitespaceAtPos that starts treating \u200B as a space makes it happy.

That might sound hacky, but formally it looks Ok and allows not introducing any additional completions settings and/or DAP capabilities. I'm happy to submit a PR if you find the approach reasonable.

[weinand]

@isidorn We can take the "hacky" fix for now, but we should start addressing this in a better way, which might involve extending the DAP.

[isidorn]

@pavelfeldman agree with your point that putting the useless properties at the end is the right thing to do.
@weinand as for extending the DAP I think the right apporach would be to go with sortText which we already expose in vscode.d.ts.

As for the hacky solution we can also go down that route, however for changes at isWhitespaceAtPos we need @jrieken approval since that would change all fuzzy scoring used by the suggest widget.
Thus I would lean towards extending the DAP.

[weinand]

Ok, I've created a DAP feature request for adding an optional sortText" to the "CompletionItem" type.

[jrieken]

With a single line change to isWhitespaceAtPos that starts treating \u200B as a space makes it happy.

Generally that's a fair change - the list of whitespace characters in definitely not complete. Anyways, the proper way to tackle this is @weinand's sortText extension.

[pavelfeldman]

Any solution works for me. DAP sourText extension sounds great. It requires more changes in VS Code itself - it seemed fairly opinionated in how it wanted to alphabetically sort items, but overall sounds like a great addition!

[weinand]

@isidorn
I've added an optional "sortText" attribute to the "CompletionItem" type.
Please implement sorting completion items based on this.

[isidorn]

Debug console now supports the sortText.
Try it out from Wednesday vscode insiders and let me know how it behaves.

[weinand]

I've added sample code for completions to mock-debug and verified that sorting completion items work.

[isidorn]

Adding verified label per @weinand comments. And seems to work for Pavel as well.