[json] JSON Schema anyOf error reporting is misleading

[jackmtpt]

Does this issue occur when all extensions are disabled?: Yes

• VS Code Version:
• OS Version:

Steps to Reproduce:

1. Save the following as repo_schema.json

{
  "$schema": "https://json-schema.org/draft-07/schema",
  "$id": "repo_schema.json",
  "type": "object",
  "properties": {
    "$schema": {
          "type": "string"
        },
    "merge_types": {
      "type": "object",
      "patternProperties": {
        "^.*$": {
          "properties": {
            "allow_squash": {
              "type": "boolean"
            },
            "allow_rebase_and_fast_forward": {
              "type": "boolean"
            },
            "allow_basic_no_fast_forward": {
              "type": "boolean"
            },
            "allow_rebase_with_merge": {
              "type": "boolean"
            }
          },
          "additionalProperties": false,
          "required": [
            "allow_squash",
            "allow_rebase_and_fast_forward",
            "allow_basic_no_fast_forward",
            "allow_rebase_with_merge"
          ],
          "anyOf": [
            {
              "properties": {
                "allow_squash": {
                  "const": true,
                  "description": "At least one merge type must be enabled."
                }
              }
            },
            {
              "properties": {
                "allow_rebase_and_fast_forward": {
                  "const": true,
                  "description": "At least one merge type must be enabled."
                }
              }
            },
            {
              "properties": {
                "allow_basic_no_fast_forward": {
                  "const": true,
                  "description": "At least one merge type must be enabled."
                }
              }
            },
            {
              "properties": {
                "allow_rebase_with_merge": {
                  "const": true,
                  "description": "At least one merge type must be enabled."
                }
              }
            }
          ]
        }
      },
      "additionalProperties": false
    }
  },
  "required": [],
  "additionalProperties": false
}

2. Save the following as test.json

{
    "$schema": "repo_schema.json",
    "merge_types": {
        "main": {
            "allow_squash": false,
            "allow_rebase_and_fast_forward": false,
            "allow_basic_no_fast_forward": false,
            "allow_rebase_with_merge": false
        }
    }
}

3. Ensure that the setting json.validate.enable=true
4. You'll get a single yellow squiggly like this:

This implies that the issue is with the first property, but in reality changing any of them to true makes the squiggly go away (which is correct).

The squiggly line should appear on all of the properties, since it's not just the first property that's failing to validate. Indeed other validators such as https://www.jsonschemavalidator.net/ do generate an error for each property:

[aeschli]

The current implementation looks at all alternatives. If all of them result in an error, it picks the one that matches most and shows the errors of that one.
In your case, they all match equally.
IMO Showing all errors es equally confusing.

[jackmtpt]

IMO Showing all errors es equally confusing.

In the case of everything matching equally why should one possibility be preferred over the others? In this example we really don't want users just blindly accepting the suggestion from VSCode, so if there's no way to configure the schema validation to show all alternatives I'll have to just remove this check from the schema and handle it in code instead which is a worse user experience since it can't be validated before commit/push.

For context this is a json file (actually yaml, but it uses the json schema validation) to define repos in Azure DevOps; users edit the files locally and a pipeline applies the changes once their PR is merged.