* fix(schema): support list-form "type" arrays in JSON schema conversion
_json_schema_to_pydantic_type already handles anyOf/oneOf for nullable
unions -- the form Pydantic's own schema generation produces for
Optional[T] fields -- but had no handling for the other, equally valid
JSON Schema way of expressing the same thing: a list-form type array,
e.g. {"type": ["string", "null"]}. This is what .NET/System.Text.Json
-based schema generators produce instead, so any MCP tool schema from
a non-Python server using this form crashed create_model_from_schema
outright with "Unsupported JSON schema type: ['string', 'null']" --
taking down the entire MCPServerAdapter connection, not just the one
affected tool.
Confirmed against a real self-hosted MCP server (Equibles,
github.com/daniel3303/Equibles): several of its tools (e.g.
ListCompanyDocuments's startDate/endDate filters) use exactly this
pattern, and MCPServerAdapter couldn't connect to it at all as a
result -- reproduced identically on both Windows and macOS.
Fix mirrors the existing anyOf/oneOf handling: treat each entry in a
list-form type the same way an anyOf member is handled, building a
Union of the corresponding Python types. A single-element list
collapses to that one type via typing.Union's own behavior, and
"null" entries resolve to None (matching how the type == "null"
branch already behaves), producing the same Optional[T] shape as the
anyOf case would.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
* fix(schema): preserve union members when applying FORMAT_TYPE_MAP
CodeRabbit flagged this reviewing #7058: the format override in
_json_schema_to_pydantic_field replaced the whole resolved type with
FORMAT_TYPE_MAP[format_], even when that type was a Union built from a
list-form `type` (or anyOf/oneOf) rather than a plain `str`. For a
schema like {"type": ["string", "null"], "format": "date-time"}, this
collapsed Union[str, None] down to plain datetime, silently dropping
the null option -- masked for non-required fields by the
Optional-rewrap at the end of the same function, but not for a
required-but-nullable field (a valid, if unusual, JSON Schema shape).
The same override also drops any non-string members of a multi-type
array (e.g. ["string", "integer", "null"]) regardless of required
status, since nothing rewraps those.
Narrow the override to the `str` member specifically: replace `type_`
outright when it's already plain `str`, or substitute only the `str`
element inside a Union via get_origin/get_args, leaving null and
other type-array members untouched.
Added two tests covering the previously-broken cases: a required
nullable formatted field, and a multi-type array (string/integer/null)
with a format.
Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
---------
Co-authored-by: Claude Sonnet 5 <noreply@anthropic.com>
Co-authored-by: Vidit Ostwal <110953813+Vidit-Ostwal@users.noreply.github.com>
resolve_refs now returns type-preserving stubs instead of {} for
circular $refs, and create_model_from_schema catches JsonRefError
to fall back to lazy top-level-only inlining.
