1.0.60 Expects type To Be Array

[tomdeering-wf]

When dependabot brought us from using json-schema-validator 1.0.59 to 1.0.60 in an internal project, many tests started failing. The root cause seems to be that json-schema-validator 1.0.60 expects that "type" should be an array rather than a simple string, even though a simple string is allowed by the spec.

Here is a test case that reproduces the issue:

{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "type": "object",
  "properties": {
    "firstName": {
      "type": "string"
    },
    "lastName": {
      "type": "string"
    },
    "address": {
      "type": "object",
      "properties": {
        "street": {
          "type": "string"
        },
        "city": {
          "type": "string"
        }
      },
      "required": [
        "street",
        "city"
      ]
    }
  },
  "required": [
    "firstName",
    "lastName",
    "address"
  ]
}

Validated using:

final var config = new SchemaValidatorsConfig();
config.addKeywordWalkListener(ValidatorTypeCode.PROPERTIES.getValue(), new JsonSchemaWalkListener() {
      private final List<ParseResult.Property> path = Lists.newArrayList();

      @Override
      public WalkFlow onWalkStart(final WalkEvent walkEvent) {
        // This method is more confusing than it should be on first blush. The reason for this is
        // that technically properties can have the literal name "properties" and can also contain
        // periods which means we need complex logic as we can use simple string splitting or
        // jsonpath. We have to track the state of our recursive descent to strip out known prefixes
        // from our current path.

        // The first event is always the outer object properties.
        if (walkEvent.getAt().equalsIgnoreCase("$")) {
          path.add(new ParseResult.Property("properties", "$.properties"));
          return WalkFlow.CONTINUE;
        }

        final var previous = path.get(path.size() - 1);
        final var path = walkEvent.getAt();

        var name = StringUtils.removeStart(path, previous.getPath() + ".");
        final var property = new ParseResult.Property(name, walkEvent.getAt());

        properties.add(property);

        final var nextProperty = new ParseResult.Property(name, walkEvent.getAt() + ".properties");
        this.path.add(nextProperty);

        return WalkFlow.CONTINUE;
      }

      @Override
      public void onWalkEnd(final WalkEvent walkEvent,
                            final Set<ValidationMessage> validationMessages) {

        this.path.remove(path.size() - 1);
      }
    });
final var jsFactory = JsonSchemaFactory.getInstance(V7);
final var schema = jsFactory.getSchema(stream /*Of draft 7 schema definition*/, config);
final var result = schema.walk(value, true);

Expected: No validation errors
Actual (1.0.59): No validation errors
Actual (1.0.60): [$.type: string found, array expected, $.properties.firstName.type: string found, array expected, $.properties.lastName.type: string found, array expected, $.properties.address.type: string found, array expected, $.properties.address.properties.street.type: string found, array expected, $.properties.address.properties.city.type: string found, array expected]

The only change that could have broken us seems to be #452, but I'm not sure how

[stevehu]

@tomdeering-wf Thanks for raising this issue. This is the reason we have short release cycles so that we can easily identify broken issues.

@bartoszm I am wondering if you could take a look at this issue?

[bartoszm]

@tomdeering-wf sure will look at it.

[stevehu]

@tomdeering-wf, I have released 1.0.61 with the fix from @bartoszm. Could you please test it to confirm the issue is resolved in your case? Thanks a lot for raising the issue. Also, thank you @bartoszm for the quick response.