Format attribute should not validate data instances that aren't the instance type to validate

[DannyvdSluijs]

Our bowtie report shows that for Draft 3 and Draft 4 has some failing tests with regards to the format attribute.

Some example of these failing test case are:

• Test: all string formats ignore integers
  • Case: email format
  • Case: ipv4 format
  • Case: ipv6 format

Draft 3 specification

From the spec we can read the following

7.1. Foreword
Structural validation alone may be insufficient to validate that an instance meets all the requirements of an application. The "format" keyword is defined to allow interoperable semantic validation for a fixed subset of values which are accurately described by authoritative resources, be they RFCs or other external specifications.

The value of this keyword is called a format attribute. It MUST be a string. A format attribute can generally only validate a given set of instance types. If the type of the instance to validate is not in this set, validation for this format attribute and instance SHOULD succeed.