SemanticTokensBuilder.buildEdits() returning incorrect deleteCount

I’m working on an issue where the users of a language server that I’m the maintainer of see their semantic coloring go haywire when doing deletes. I’ve confirmed that if I modify my language server to provide full tokens for a document every time (it currently registers as a full and delta provider), the tokens are correct after a delete. However, when registering as a delta provider and using the SemanticTokensBuilder.buildEdits() function, I observe this behavior:

My document upon open contains this text:

Class User.short
{

/// desc
ClassMethod t()
{
    q 1
}

}

And these tokens:

[ 0, 0, 5, 4, 0 ]
[ 0, 6, 4, 5, 0 ]
[ 0, 4, 1, 5, 0 ]
[ 0, 1, 5, 5, 0 ]
[ 1, 0, 1, 8, 0 ]
[ 2, 0, 3, 7, 0 ]
[ 0, 4, 4, 7, 0 ]
[ 1, 0, 11, 4, 0 ]
[ 0, 12, 1, 11, 0 ]
[ 0, 1, 2, 8, 0 ]
[ 1, 0, 1, 8, 0 ]
[ 1, 4, 1, 60, 0 ]
[ 0, 2, 1, 51, 0 ]
[ 1, 0, 1, 8, 0 ]
[ 2, 0, 1, 8, 0 ]

If I delete the line /// desc (tokens 6 & 7), the result of textDocument/semanticTokens/full/delta is:

{
    "resultId": "1618608792098",
    "edits": [
        {
            "start": 27,
            "deleteCount": 9,
            "data": []
        }
    ]
}

and the expected result is:

{
    "resultId": "1618608792098",
    "edits": [
        {
            "start": 27,
            "deleteCount": 10,
            "data": []
        }
    ]
}

I’m using VSCode 1.55.2 and vscode-languageclient/server 7.0.0

Original issue: https://github.com/intersystems/language-server/issues/29

[dbaeumer]

Release server@7.1.0-next.5 and client@7.1.0-next.5

[dbaeumer]

Sorry for that. I can make a next version beginning on next week.