savannahostrowski · Nov 12, 2026 · May 8, 2026 · May 8, 2026 · Nov 6, 2026 · Nov 6, 2026
diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
@@ -8,19 +8,6 @@ name: ci
       - main
 
 jobs:
-  lint:
-    runs-on: ubuntu-latest
-    steps:
-      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
-      - uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
-        with:
-          python-version: "3.11"
-          cache: pip
-      - name: Install dependencies
-        run: python -m pip install .[test]
-      - name: Run lints
-        run: ./lint.sh
-
   test:
     runs-on: ubuntu-latest
     strategy:

diff --git a/.github/workflows/lint.yml b/.github/workflows/lint.yml
@@ -0,0 +1,21 @@
+---
+name: lint
+
+"on":
+  pull_request:
+  push:
+    branches:
+      - main
+
+jobs:
+  lint:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+      - uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
+        with:
+          python-version: "3.11"
+          cache: pip
+      - name: Install dependencies
+        run: python -m pip install ".[test]"
+      - uses: j178/prek-action@1382ad72dea72f9d53832f2bcb65b3e87a947204 # v3.0.1
diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
@@ -0,0 +1,18 @@
+repos:
+  - repo: https://github.com/astral-sh/ruff-pre-commit
+    rev: e05c5c0818279e5ac248ac9e954431ba58865e61  # frozen: v0.15.7
+    hooks:
+      - id: ruff-check
+        args: [--exit-non-zero-on-fix]
+      - id: ruff-format
+        args: [--exit-non-zero-on-fix]
+
+  - repo: local
+    hooks:
+      - id: pyright
+        name: pyright
+        entry: python -m pyright bench_runner
+        language: system
+        pass_filenames: false
+        types: [python]
+        stages: [pre-commit]
diff --git a/DEVELOPER.md b/DEVELOPER.md
@@ -2,6 +2,17 @@
 
 This repository contains a number of GitHub Actions workflows to run benchmarks on a set of private, self-hosted, bare metal machines.
 
+## Linting
+
+We recommend [prek](https://prek.j178.dev/) to run the hooks in
+`.pre-commit-config.yaml`. From the repository root, with a virtual environment active:
+
+```sh
+python -m pip install -e ".[test]" prek
+prek install
+prek run --all-files
+```
+
 ## The workflows
 
 There is a single user-facing workflow, `benchmark.yml`, that [reuses](https://docs.github.com/en/actions/using-workflows/reusing-workflows) the other workflows, prefixed with `_`.

diff --git a/bench_runner/config.py b/bench_runner/config.py
@@ -82,7 +82,8 @@ def __post_init__(self):
             )
         self.runners = {
             name: mrunners.Runner(
-                nickname=name, **runner  # pyright: ignore[reportCallIssue]
+                nickname=name,
+                **runner,  # pyright: ignore[reportCallIssue]
             )
             for name, runner in self.runners.items()
         }

diff --git a/bench_runner/plot.py b/bench_runner/plot.py
@@ -248,9 +248,9 @@ def __post_init__(self):
 def longitudinal_plot(
     results: Iterable[result.Result],
     output_filename: PathLike,
-    getter: Callable[
-        [result.BenchmarkComparison], float | None
-    ] = lambda r: r.geometric_mean_float,
+    getter: Callable[[result.BenchmarkComparison], float | None] = lambda r: (
+        r.geometric_mean_float
+    ),
     differences: tuple[str, str] = ("slower", "faster"),
     title="Performance improvement by configuration",
 ):
@@ -442,9 +442,9 @@ def __post_init__(self):
 def flag_effect_plot(
     results: Iterable[result.Result],
     output_filename: PathLike,
-    getter: Callable[
-        [result.BenchmarkComparison], float | None
-    ] = lambda r: r.geometric_mean_float,
+    getter: Callable[[result.BenchmarkComparison], float | None] = lambda r: (
+        r.geometric_mean_float
+    ),
     differences: tuple[str, str] = ("slower", "faster"),
     title="Performance improvement by configuration",
 ):
@@ -496,11 +496,10 @@ def get_comparison_value(ref, r, force_valid):
         ] = r
 
     for subplot, ax in zip(subplots, axs):
-
         ax.set_title(f"Effect of {subplot.name}")
         version = tuple(int(x) for x in subplot.version.split("."))
         assert len(version) == 2, (
-            "Version config in {subplot.name}" " should only be major.minor"
+            "Version config in {subplot.name} should only be major.minor"
         )
 
         for runner in cfg.runners.values():

diff --git a/bench_runner/result.py b/bench_runner/result.py
@@ -280,7 +280,7 @@ def _calculate_geometric_mean(self) -> str:
         elif gm > 1.0:
             return f"{gm:.03f}x faster"
         else:
-            return f"{1.0+(1.0-gm):.03f}x slower"
+            return f"{1.0 + (1.0 - gm):.03f}x slower"
 
     @property
     def geometric_mean(self) -> str:
@@ -874,9 +874,7 @@ def track(it, *_args, **_kwargs):
                 result,
                 candidates,
                 "base",
-                lambda ref: (
-                    ref.cpython_hash == result.cpython_hash and ref.flags == []
-                ),
+                lambda ref: ref.cpython_hash == result.cpython_hash and ref.flags == [],
             )
 
 

diff --git a/bench_runner/scripts/compare.py b/bench_runner/scripts/compare.py
@@ -61,7 +61,7 @@ def compare_pair(
     output_dir = Path(output_dir)
 
     rich.print(
-        f"Comparing {counter[0]+1: 2}/{counter[1]: 2}: {head_name} vs. {ref_name}"
+        f"Comparing {counter[0] + 1: 2}/{counter[1]: 2}: {head_name} vs. {ref_name}"
     )
     counter[0] += 1
 

diff --git a/bench_runner/scripts/install.py b/bench_runner/scripts/install.py
@@ -226,9 +226,9 @@ def generate_benchmark(dst: Any) -> Any:
             continue
         if "with" in job:
             for flag in flags.FLAGS:
-                job["with"][
-                    flag.gha_variable
-                ] = f"${{{{ inputs.{flag.gha_variable} }}}}"
+                job["with"][flag.gha_variable] = (
+                    f"${{{{ inputs.{flag.gha_variable} }}}}"
+                )
 
     # Include all of the flags in the human-readable workflow "run name"
     dst["run-name"] += " " + " ".join(

diff --git a/bench_runner/scripts/run_benchmarks.py b/bench_runner/scripts/run_benchmarks.py
@@ -337,8 +337,8 @@ def run_summarize_stats(
     - benchmark: {benchmark}
     - fork: {fork}
     - ref: {ref}
-    - commit hash: {git.get_git_hash(Path('cpython'))[:7]}
-    - commit date: {git.get_git_commit_date(Path('cpython'))}
+    - commit hash: {git.get_git_hash(Path("cpython"))[:7]}
+    - commit date: {git.get_git_commit_date(Path("cpython"))}
 
     """
     )

diff --git a/bench_runner/table.py b/bench_runner/table.py
@@ -18,7 +18,7 @@ def output_table(
     """
 
     def output_row(row):
-        fd.write(f'| {" | ".join(row)} |\n')
+        fd.write(f"| {' | '.join(row)} |\n")
 
     output_row(head)
     output_row(col.endswith(":") and "---:" or "---" for col in head)

diff --git a/lint.sh b/lint.sh
diff --git a/pyproject.toml b/pyproject.toml
@@ -27,9 +27,7 @@ dynamic = ["version"]
 
 [project.optional-dependencies]
 test = [
-    "black==25.1.0",
     "filelock==4.2.9",
-    "flake8==7.5.0",
     "pyright==1.1.414",
     "pytest==9.2.0",
     "pytest-cov==6.2.1",
@@ -44,6 +42,15 @@ include-package-data = true
 [tool.setuptools.package-data]
 bench_runner = ["templates/*"]
 
+[tool.ruff]
+target-version = "py311"
+line-length = 88
+fix = true
+
+[tool.ruff.lint]
+extend-select = ["W605"]
+extend-ignore = ["E203", "E402"]
+
 [tool.pytest.ini_options]
 markers = [
     "long_running: marks tests as long_running (deselect with '-m \"not running\"')",
@@ -54,4 +61,4 @@ source = [
     "bench_runner",
     "/tmp/pytest-of-*/pytest-*/*/repo/outer_venv/lib/python*/site-packages/bench_runner",
     "/tmp/pytest-of-*/pytest-*/*/repo/venv/lib/python*/site-packages/bench_runner",
-]
+]
diff --git a/setup.cfg b/setup.cfg
diff --git a/tests/test_generate_results.py b/tests/test_generate_results.py
@@ -76,9 +76,9 @@ def test_main(tmp_path, monkeypatch):
     )
     with open(result_with_base) as fd:
         contents = json.load(fd)
-    contents["metadata"][
-        "commit_merge_base"
-    ] = "9d38120e335357a3b294277fd5eff0a10e46e043"
+    contents["metadata"]["commit_merge_base"] = (
+        "9d38120e335357a3b294277fd5eff0a10e46e043"
+    )
     with open(result_with_base, "w") as fd:
         json.dump(contents, fd)
     # End hack

diff --git a/tests/test_result.py b/tests/test_result.py
@@ -57,9 +57,9 @@ def test_merge_base(tmp_path, monkeypatch):
     )
     with open(result_with_base) as fd:
         contents = json.load(fd)
-    contents["metadata"][
-        "commit_merge_base"
-    ] = "9d38120e335357a3b294277fd5eff0a10e46e043"
+    contents["metadata"]["commit_merge_base"] = (
+        "9d38120e335357a3b294277fd5eff0a10e46e043"
+    )
     with open(result_with_base, "w") as fd:
         json.dump(contents, fd)
     # End hack