rety 0.2.0

One codebase. Multiple type checkers. One honest view.

Install · Usage · Development · License

rety runs mypy, Pyright, Pyrefly, and ty on the same Python code, normalizes their diagnostics, and shows where they agree, where they disagree, and why.

$ rety check src/

  src/api.py ────────────────────────────────────────────────
  3/4  * HIGH  L42  in handle_request  [Call]
      mypy      error    42:18  Argument 1 to "process" has incompatible type "str"; expected "int" [arg-type]
      pyright   error    42:18  Argument of type "str" cannot be assigned to parameter "x" of type "int" [reportArgumentType]
      pyrefly   error    42:18  Expected `int`, got `str` [bad-argument-type]

Install

pipx install rety
# or
uv tool install rety

Usage

rety check src/                          # run all available checkers
rety check --checker mypy,pyright src/   # run specific checkers
rety check --format json src/            # machine-readable output
rety check --verbose src/                # show why diagnostics were grouped
rety check --fail-on error src/          # exit 1 on errors (for CI)
rety check --python .venv/bin/python src/  # make every checker use your project's environment

Exit codes

By default (--fail-on none) rety exits 0 whenever the run itself succeeded, regardless of what the checkers found.

Confidence scores

Confidence reflects cross-checker evidence only:

Use as a library

from rety import ALL_ADAPTERS, run_checkers
from rety.align import align

adapters = [ALL_ADAPTERS[name]() for name in ("mypy", "pyright")]
results = run_checkers(adapters, paths=["src"], cwd="/path/to/project")
diagnostics = [d for r in results if r.succeeded for d in r.diagnostics]
for cluster in align(diagnostics, root="/path/to/project"):
    print(cluster.checkers_present, cluster.confidence, cluster.file)

Development

uv sync --all-groups
uv run pytest -q
uv run mypy src
uv run ruff check src tests

License

MIT