`strictTypes` does not expect "narrowing" `integer` with number keywords

[JacobLey]

What version of Ajv are you using? Does the issue happen if you use the latest version?

8.10.0 With all included schemas (default, 2019, 2020)

Ajv options object

{ strictTypes: true }

JSON Schema

{
    "type": "number",
    "if": {
        "type": "integer",
        "maximum": 5
     },
     "else": {
         "minimum": 10
     }
}

In english: A number that must be an integer <= 5, or any number >= 10.

Sample data

Resolves as follows if strictTypes is 'log' or false

4 // valid
4.5 // invalid
7 // invalid
11.5 // valid
"" // invalid
null // invalid

Your code

new Ajv({ strictTypes: true }).compile({
    type: 'number',
    if: {
        type: 'integer',
        maximum: 5
     },
     else {
         minimum: 10
     }
});

Validation result, data AFTER validation, error messages

Error: strict mode: missing type "number" for keyword "maximum" at "#/if" (strictTypes)

What results did you expect? No error message.

Documentation of strictTypes

"number" vs "integer" Type "number" can be narrowed to "integer", the opposite would violate strictTypes.

maximum is a valid keyword for integer type, which is a "narrowing" of number.

Note that the else does not error on missing type: 'number' and the error goes away if type: 'integer' is removed (as type is properly inferred from parent schema). Error also goes away if maximum: 5 is removed.

Dropping type: 'integer' or maximum: 5, would logically alter schema, as above examples of 4.5 and 7 would then be valid.

Are you going to resolve the issue? Current local solution for me is to drop strictTypes (which does not impact validation, but is an overall appreciated feature).

I'd be open to taking a swing at resolving, but would probably need some serious guidance on where to even start.

[JacobLey]

new Ajv({ strictTypes: true }).compile({
    type: 'number',
    if: {
        allOf: [
            { type: 'integer' },
            { maximum: 5 }
        ]
     },
     else {
         minimum: 10
     }
});

Appears to perform as expected with no errors. But IMHO that makes the schema less readable, and should not be necessary given the documentation of strictTypes handling of number -> integer

[epoberezkin]

yes, agreed, the logic for tracking types should be extended to ifs