0.28.8: malformed JSON response to `initialize` message

Using 0.28.8, the JSON that comes back from an initialize message looks like this:

{
    "jsonrpc": "2.0",
    "id": 1,
    "result": {
        "capabilities": {
            "textDocumentSync": {
                "openClose": true,
                "change": 2,
                "willSave": false,
                "willSaveWaitUntil": false,
                "save": true
            },
            "completionProvider": {
                "triggerCharacters": [
                    ".",
                    "'",
                    "\""
                ],
                "resolveProvider": true
            },
            "hoverProvider": true,
            "signatureHelpProvider": {
                "triggerCharacters": [
                    "(",
                    ","
                ]
            },
            "declarationProvider": null,
            "definitionProvider": true,
            "typeDefinitionProvider": null,
            "implementationProvider": null,
            "referencesProvider": true,
            "documentHighlightProvider": true,
            "documentSymbolProvider": true,
            "codeActionProvider": {
                "codeActionKinds": [
                    "refactor.inline",
                    "refactor.extract"
                ]
            },
            "codeLensProvider": null,
            "documentLinkProvider": null,
            "colorProvider": null,
            "documentFormattingProvider": null,
            "documentRangeFormattingProvider": null,
            "documentOnTypeFormattingProvider": null,
            "renameProvider": true,
            "foldingRangeProvider": null,
            "executeCommandProvider": {
                "commands": []
            },
            "selectionRangeProvider": null,
            "workspaceSymbolProvider": true,
            "workspace": {
                "workspaceFolders": {
                    "supported": true,
                    "changeNotifications": true
                }
            }
        }
    }
}

The null values for declarationProvider and others aren’t correct. According to the spec, those values should be true or false, and null isn’t translatable to a Boolean.

Because those keys are optional, it may be better to omit them entirely rather than reporting null; but if that’s not an option, false is probably a better choice.

This appears to be a regression from previous versions, which omitted those keys.

[dimbleby]

pygls fix is now released in their 0.10.3

[siegel]

@pappasam Yes! It appears to be resolved; I’m not seeing any null values coming back.