fix: handle boolean JSON Schema nodes in JsonSchemaTransformer

[Dharit13]

• Closes JsonSchemaTransformer crashes on valid boolean JSON Schema nodes #4771

Summary

JsonSchemaTransformer.walk() crashes with AttributeError: 'bool' object has no attribute 'get' when a JSON Schema contains boolean schema nodes (e.g. "value": true). Boolean schemas are valid per the JSON Schema spec (true is equivalent to {}, false is equivalent to {"not": {}}), but the walker unconditionally called .get() on every child node assuming it was a dict.

This PR treats boolean schema nodes as terminal leaves in the internal walker so they pass through untouched, and adds a parametrized regression test covering both True and False.

Pre-Review Checklist

• Any AI generated code has been reviewed line-by-line by the human PR author, who stands by it.
• No breaking changes in accordance with the version policy.
• Linting and type checking pass per make format and make typecheck.
• PR title is fit for the release changelog.

Pre-Merge Checklist

• New tests for any fix or new behavior, maintaining 100% coverage.
• Updated documentation for new features and behaviors, including docstrings for API docs.

Made with Cursor

[devin-ai-integration]

Devin Review found 1 new potential issue.

View 6 additional findings in Devin Review.

[devin-ai-integration]

🚩 OpenAI transformer's result.update(self.defs.get(root_key) or {}) is fragile with widened defs type

The PR widens self.defs from dict[str, JsonSchema] to dict[str, _JsonSchemaNode] at pydantic_ai_slim/pydantic_ai/_json_schema.py:49. The OpenAIJsonSchemaTransformer.walk() at pydantic_ai_slim/pydantic_ai/profiles/openai.py:251 does result.update(self.defs.get(root_key) or {}). If root_key maps to True, True or {} evaluates to True, and result.update(True) raises TypeError: 'bool' object is not iterable. If it maps to False, False or {} silently produces {}, losing the false schema semantics. This is only reachable if a root-level $ref points to a boolean $def, which pydantic never generates — so it's a theoretical concern rather than a practical one. But the type system now claims to support it.

(Refers to line 49)

---

Was this helpful? React with 👍 or 👎 to provide feedback.

[Dharit13]

Re: Devin Review comment on self.defs type widening

This was addressed in the latest push. self.defs is typed as dict[str, JsonSchema] (not _JsonSchemaNode), so .get(root_key) can only return dict[str, Any] | None, never a bool.

Boolean schema nodes only appear inline (as property values, array items, union members) and are handled as terminal leaves in _handle(). They never appear as $defs entries per the JSON Schema spec, so widening self.defs was unnecessary and has been reverted.

The result.update(self.defs.get(root_key) or {}) line in profiles/openai.py:251 is unaffected by this PR.