UnhandledPromiseRejectionWarning: TypeError: Cannot create property 'url' on string 'string'

Describe the bug

When I am editing a YAML file with my custom schema, it validates properly and gives me an error highlight once, but when I fix the error, the highlight never goes away. When I look at the message log, I see a traceback:

[Error - 9:17:30 PM] (node:96798) UnhandledPromiseRejectionWarning: TypeError: Cannot create property 'url' on string 'string'
    at _validateObjectNode (/Users/pprescod/.vscode/extensions/redhat.vscode-yaml-0.22.0/node_modules/yaml-language-server/out/server/src/languageservice/parser/jsonParser07.js:983:44)
    at validate (/Users/pprescod/.vscode/extensions/redhat.vscode-yaml-0.22.0/node_modules/yaml-language-server/out/server/src/languageservice/parser/jsonParser07.js:438:13)
    at _validateArrayNode (/Users/pprescod/.vscode/extensions/redhat.vscode-yaml-0.22.0/node_modules/yaml-language-server/out/server/src/languageservice/parser/jsonParser07.js:843:21)
    at validate (/Users/pprescod/.vscode/extensions/redhat.vscode-yaml-0.22.0/node_modules/yaml-language-server/out/server/src/languageservice/parser/jsonParser07.js:441:13)
    at SingleYAMLDocument.validate (/Users/pprescod/.vscode/extensions/redhat.vscode-yaml-0.22.0/node_modules/yaml-language-server/out/server/src/languageservice/parser/jsonParser07.js:398:13)
    at getDiagnostics (/Users/pprescod/.vscode/extensions/redhat.vscode-yaml-0.22.0/node_modules/vscode-json-languageservice/lib/umd/services/jsonValidation.js:69:59)
    at /Users/pprescod/.vscode/extensions/redhat.vscode-yaml-0.22.0/node_modules/vscode-json-languageservice/lib/umd/services/jsonValidation.js:106:24

jsonParser07.js line 983 is

propertySchema.url = (_a = schema.url) !== null && _a !== void 0 ? _a : originalSchema.url;

Expected Behavior

Errors should change as I edit my file. No tracebacks.

Steps to Reproduce

1. Create this Schema file:

{
    "$id": "https://github.com/SFDO-Tooling/Snowfakery/schema/snowfakery_recipe.schema.json",
    "description": "Snowfakery recipe.",
    "type": "array",
    "minItems": 1
}

2. Create a related Schema

yaml-language-server: $schema=file:snowfakery_recipe.schema.json

• object: fooboffsef
  fields:
  foo: bar

3. Change the file URL to be appropriate for your setup.

4. Try changing - object: fooboffsef to - objectxxx: fooboffsef to get a validation error.

5. Change it back.

Environment

• Windows
• [ X] Mac
• Linux
• other (please specify)

Reproduce the YAML-schema edit cycle and trace validation through jsonParser07.js, especially _validateObjectNode, _validateArrayNode, and SingleYAMLDocument.validate around the reported line. Confirm that changing the invalid property back no longer produces an UnhandledPromiseRejectionWarning and that diagnostics update correctly without a stale highlight.