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json schema: propertyNames only shows up under specific conditions #866
Description
Description
I found a weird inconsistency when generating JSON schema:
Variant 1
import msgspec
from typing import Annotated
import json
key_type = Annotated[str, msgspec.Meta(pattern=r'^A$')]
value_type = Annotated[str, msgspec.Meta(pattern=r'^B$')]
dict_type = Annotated[dict[key_type, value_type], msgspec.Meta(min_length=1)]
schema = msgspec.json.schema(dict_type)
print(json.dumps(schema, indent=2))results in:
{
"type": "object",
"propertyNames": {
"pattern": "^A$"
},
"additionalProperties": {
"type": "string",
"pattern": "^B$"
},
"minProperties": 1
}✔️ works as expected
Variant 2
import msgspec
from typing import Annotated
import json
key_type = Annotated[str, msgspec.Meta(title='key', pattern=r'^A$')]
value_type = Annotated[str, msgspec.Meta(pattern=r'^B$')]
dict_type = Annotated[dict[key_type, value_type], msgspec.Meta(min_length=1)]
schema = msgspec.json.schema(dict_type)
print(json.dumps(schema, indent=2))results in:
{
"type": "object",
"additionalProperties": {
"type": "string",
"pattern": "^B$"
},
"minProperties": 1
}❌ Merely adding the title kwarg to key_type results in the propertyNames section being dropped entirely.
Activity
[-]json schema: propertyNames only show up under specific conditions[/-][+]json schema: propertyNames only shows up under specific conditions[/+]Fix JSON schema metadata for dictionary keys (msgspec#1159)