[HTML] server contains invalid implementation of applyEdit

[idanarye]

The protocol has changed to define that multiple edits can have the same position, and should be applied using the order inside the array. The current implementation in VSCode, however, is using unstable sort - meaning the order they will be applied in will be arbitrary.

Specifically, with one equivalence class TypeScript's current implementation of sort will reverse the array - which is exactly the opposite of what the specs specify.

To be compliant with the specs, VSCode must use stable sort on the edits.

[jrieken]

I believe this is @dbaeumer or @aeschli and not the extension api. Fyi, for stable sorting there is arrays#mergeSort

[dbaeumer]

@aeschli assigning to you since this is specifiic HTML code.

@idanarye the editor which usually applies these edits does us a stable sort. So the actual VS Code API is fine in that regard.

[idanarye]

@dbaeumer What do you mean by "the editor which usually applies these edits"? VSCode uses unstable sort (unless it overrides TypeScript's array#sort with a stable implementation?), and other editors, which looked at VSCode's behavior as reference, do a stable sort after reversing the edits - because this happens to be what the current implementation of array#sort does for a single equivalence class.

[dbaeumer]

@idanarye VS Code offers API for extension to apply edits to an open buffer. When this API is called the editor itself sorts the array using a stable sort algorithm as defined in the LSP spec.

See: https://github.com/Microsoft/vscode/blob/master/src/vs/vscode.d.ts#L5556