`pfg polyfactory migrate`

Polyfactory adopters can inventory existing ModelFactory overrides and auto-generate fixturegen config snippets instead of rewriting factories by hand. The command inspects every discovered factory, compares its field overrides to fixturegen’s current provider plan, and emits actionable reports plus [tool.pydantic_fixturegen.overrides] entries.

Highlights

Detects Use, Ignore, Require, PostGenerated, and literal field overrides defined on Polyfactory classes.
Shows the provider/heuristic fixturegen would use today so you can decide whether an override is still required.
Translates supported overrides into fixturegen config that relies on helper adapters (invoke_use, invoke_post_generate) so callables keep working.
Flags unsupported constructs (lambdas, non-serializable values, nested factories, etc.) so you know where manual work remains.

Usage

pfg polyfactory migrate ./app/models.py \

  --include app.models.User \

  --factory-module app.factories \

  --overrides-out overrides-polyfactory.toml

Key options

Flag	Description
`TARGET`	Path to a Python module containing Pydantic models. Required.
`--include/-i`, `--exclude/-e`	Glob filters (comma-separated) applied before discovery.
`--factory-module/-m`	Extra module(s) to scan for Polyfactory factories (repeatable, mirrors `[polyfactory].modules`).
`--format/-f`	`table` (default) for a readable report or `json` for machine processing.
`--overrides-out`	Write translated overrides to a TOML file that can be merged into `pyproject.toml`.

The command loads the current configuration (presets, heuristics, provider defaults, etc.) so the fixturegen provider columns in the report match what your next pfg gen ... run would use.

Sample table output

Model: app.models.User

Factory: app.factories.UserFactory

  - slug [translated]

      Polyfactory: Use(slugify)

      Fixturegen: string:slug [heuristic:slug-format]

      Override: {"factory": "pydantic_fixturegen.polyfactory_support.migration_helpers:invoke_use", "factory_args": ["app.factories:slugify", ["user-"], {}]}

  - alias [translated]

      Polyfactory: Ignore()

      Fixturegen: string

      Override: {"ignore": true}

  - legacy_id [manual]

      Polyfactory: Use(<lambda>)

      Fixturegen: string

      Note: callable could not be resolved

With --format json the same data is emitted as structured JSON so you can feed it into custom tooling or dashboards.

Generated overrides

Whenever translation succeeds the command aggregates a [tool.pydantic_fixturegen.overrides] snippet. The helper adapters live in pydantic_fixturegen.polyfactory_support.migration_helpers and handle bridging fixturegen’s override API with Polyfactory’s callable semantics.

[tool.pydantic_fixturegen.overrides."app.models.User".slug]

factory = "pydantic_fixturegen.polyfactory_support.migration_helpers:invoke_use"

factory_args = ["app.factories:slugify", ["user-"], {}]

[tool.pydantic_fixturegen.overrides."app.models.User".alias]

ignore = true

The adapters expect importable callable paths (either module:attr or dotted module paths). If a callable cannot be resolved (lambdas, closures, dynamically generated functions), the report lists it under the “manual” bucket so you can decide how to recreate the behaviour.

Workflow

Run pfg polyfactory migrate against your project module.
Address any “manual” notes in the report (rewrite lambdas, export helper functions, etc.).
Merge the generated TOML snippet into [tool.pydantic_fixturegen.overrides].
Re-run pfg coverage report / pfg doctor or spot-check with pfg gen explain to validate that fixturegen now honours the overrides.
Remove the original Polyfactory factories when you’re satisfied with the parity.

ℹ️ The command requires the polyfactory extra (pip install "pydantic-fixturegen[polyfactory]"). On Python 3.14+ you must opt in via PFG_POLYFACTORY__ALLOW_PY314=1 because upstream Polyfactory still depends on Pydantic v1 APIs.

Edit this page