pydantic-devtools

A collection of utilities to facilitate debugging of Pydantic's internals.

Pretty-print core schemas

The pps() function can be used to debug Pydantic core schemas:

class Model(BaseModel): ...

# If the provided argument is a Pydantic model/dataclass type adapter,
# the core schema is automatically fetched:
pps(
    Model,
    max_depth=2,  # Default: None
    strip_metadata=False  # Default: True
)
> {
>     'type': 'model',
>     ...,
> }

The Pydantic debugger

pydantic-devtools provides a custom Pdb class, adding various commands.pps (pretty-print schema) command to debug Pydantic core schemas.

To use the Pydantic debugger:

• set the PYTHONBREAKPOINT environment variable to pydantic_devtools.pdb.
• In your code, add a breakpoint() call. The Pydantic debugger will be used.

pps command

The pps (pretty-print schema) command can be used to debug Pydantic core schemas (same as the pps() function):

(Pydantic pdb) pps schema
{
    'type': 'model-field',
    'schema': {'type': 'definition-ref', 'schema_ref': '...'},
    'metadata': {'<stripped>'}
}

By default, generic metadata (related to JSON Schema generation) is stripped.

Optionally, a max_depth argument can be provided (pps <schema> <depth>). A default value can also be specified as a keyword argument to breakpoint().

pc command

The pc (Pydantic context) command can be used to get information related to the current schema generation process: