This approach isn't going to work. Try,

{
  "allOf": [
    { "const": "a" },
    { "const": "b" }
  ]
}

Hi @jdesrosiers,

thanks for pointing out the issue! I understood the problem:

Issue: with a schema like above one -> allOf: [{ const: "a" }, { const: "b" }], if the instance is "a"

• const: "a" passes (not in errors)
• Only const: "b" fails
• My original code only saw failing constraints -> couldn't detect the contradiction
• My Solution: I updated the handler to collect ALL constraints (both passing and failing), then compute the intersection:

const passed = normalizedErrors[...][schemaLocation] === true;
if (!passed) hasFailure = true;
// always collect
constraints.push({ allowedValues: [...], schemaLocation });

now:

• Both ["a"] and ["b"] are collected
• Intersection = [] (empty)
• Returns getBooleanSchemaErrorMessage()

Tests Added:

• contradictory const - empty intersection (instance matches one const)
• contradictory enum - empty intersection (disjoint enum sets)

All tests pass. Is this approach good, or does it need further improvements?
Thanks!