feat: extend allowed_values option of JSONSchema for Property(ArrayType)

[TyShkan]

Feature scope

Taps (catalog, state, stream maps, etc.)

Description

Currently it's not possible to set allowed_values for Property(ArrayType) since it generates schema like following:

"property_name": {
    "type": ["array", "null"],
    "items": {"type": ["string"]},
    "enum": ["allowed_value1", "allowed_value2"]
}

And checks only types like Integer, String, etc, not arrays.

In order to validate array's allowed values the schema should look like following:

"property_name": {
    "type": ["array", "null"],
    "items": {
        "type": ["string"],
        "enum": ["allowed_value1", "allowed_value2"]
    }
}

Looks like the changes should be implemented here:

sdk/singer_sdk/typing.py

Line 479 in 0948c77

if self.allowed_values:

Something like:

if self.allowed_values:
    if type is array: # pseudocode
        type_dict["items"].update({"enum": self.allowed_values}) # just a concept
    else:
        type_dict.update({"enum": self.allowed_values})

[TyShkan]

Slack thread

[TyShkan]

Would be solved here: #1603