⚡ perf(workflows): install only the formatter hook

.github/workflows/prepare-release-creator.yaml

@@ -106,12 +106,6 @@ jobs:
         with:
           crate: cargo-edit
           version: 0.13.13
-      - name: 🧹 Install prek hooks
-        id: hooks
-        uses: $/cooled-prek
-        with:
-          args: install-hooks
-        background: true
       - name: 🏷️ Select release version
         id: version
         env:
@@ -203,8 +197,6 @@ jobs:
             args+=(--package "$PACKAGE")
           fi
           release-creator contributors "${args[@]}"
-      - name: ⏳ Wait for prek hooks
-        wait: hooks
       - name: 🧹 Format changelog
         id: format
         continue-on-error: true

.github/workflows/prepare-towncrier-release.yaml

@@ -73,12 +73,6 @@ jobs:
           venv: .venv
           exclude-newer: ${{ inputs.exclude-newer }}
           exclude-newer-package: ${{ inputs.exclude-newer-package }}
-      - name: 🧹 Install prek hooks
-        id: hooks
-        uses: $/cooled-prek
-        with:
-          args: install-hooks
-        background: true
       - id: prepare
         name: 📝 Build changelog
         uses: $/prepare-towncrier
@@ -87,8 +81,6 @@ jobs:
           tag-prefix: ${{ inputs.tag-prefix }}
           changelog-prefix: ${{ inputs.changelog-prefix }}
           phase: build
-      - name: ⏳ Wait for prek hooks
-        wait: hooks
       - name: 📝 Finalize release patch
         uses: $/prepare-towncrier
         with:

README.md

@@ -586,8 +586,8 @@ these examples means that commit.
 
 Assembly needs release history to select a tag. The writer can check out the source commit with `fetch-depth: 1`. All
 jobs use `persist-credentials: false`. Assembly installs the caller's locked release tools and needs `contents: read`
-and `pull-requests: read` to resolve PR authors. It starts `prek install-hooks` while building the changelog, then waits
-for the hooks before formatting and uploading the patch. The writer uses the `release-auth` environment with
+and `pull-requests: read` to resolve PR authors. It installs only the changelog formatter's hook, when it formats, so a
+hook the release never runs cannot fail it. The writer uses the `release-auth` environment with
 `RELEASE_APP_PRIVATE_KEY` and `RELEASE_APP_CLIENT_ID`. Restrict that environment to `main`. Install the App on this
 repository only, with Contents write and Metadata read, and grant the necessary branch and tag ruleset bypass.
 
@@ -653,11 +653,11 @@ token exists. Trigger the caller on `push`, `schedule`, `workflow_dispatch`, or
 
 ### Dry run on pull requests
 
-A release assembles under rules a pull request's own checks never apply: hooks install with packages from the last seven
-days held back, fragments link to their pull requests, and the changelog builds and formats. A pull request that breaks
-any of these merges green and fails the next release. `dry-run: true` runs `assemble` alone and skips `push`, so the
-pull request fails instead. A dry run needs no App key and uses its own concurrency group per ref, so it never queues
-behind a real release.
+A release assembles under rules a pull request's own checks never apply: the changelog formatter's hook installs with
+packages from the last seven days held back, fragments link to their pull requests, and the changelog builds and
+formats. A pull request that breaks any of these merges green and fails the next release. `dry-run: true` runs
+`assemble` alone and skips `push`, so the pull request fails instead. A dry run needs no App key and uses its own
+concurrency group per ref, so it never queues behind a real release.
 
 Make the caller's prepare workflow callable and run it from the workflow that holds the required gate, so the dry run
 uses the same inputs as the release:
@@ -747,8 +747,8 @@ formatting must all succeed.
   whose release headings use `v1.2.3`.
 - `version`: Explicit version for a caller with its own version selector. It takes precedence over `bump`.
 - `phase`: `all` (default) runs the complete Action. The reusable workflow uses `build` to select the version, link
-  authors, and build the changelog while hooks install; it then uses `finalize` to format, render, and write the patch.
-  Pass the version selected by `build` to `finalize`.
+  authors, and build the changelog; it then uses `finalize` to format, render, and write the patch. Pass the version
+  selected by `build` to `finalize`.
 
 The committed `tool.towncrier` configuration gives the `filename` and `directory`. `docstrfmt` formats a `.rst`
 changelog and `mdformat` any other; the formatter must be a configured `prek` hook. The Action writes the patch at

changelog.d/+install-one-hook.performance.md

@@ -0,0 +1,3 @@
+`prepare-towncrier-release` and `prepare-release-creator` install only the changelog formatter's hook instead of every
+hook, so release preparation and its pull request dry run finish faster, and a hook the release never runs cannot fail
+it.

tests/cooled_prek/test_cooled_prek.py

@@ -5,6 +5,7 @@
 import subprocess
 from pathlib import Path
 
+import pytest
 import yaml
 from conftest import action
 
@@ -31,14 +32,13 @@ def test_no_hook_run_bypasses_cooled_prek() -> None:
     assert not commands, commands
 
 
-def test_prepare_hook_install_uses_cooled_prek() -> None:
+@pytest.mark.parametrize("name", ["prepare-towncrier-release.yaml", "prepare-release-creator.yaml"])
+def test_prepare_installs_no_hook_it_does_not_run(name: str) -> None:
     workflow = yaml.load(
-        (Path(__file__).resolve().parents[2] / ".github/workflows/prepare-towncrier-release.yaml").read_text(),
-        Loader=yaml.BaseLoader,
+        (Path(__file__).resolve().parents[2] / ".github/workflows" / name).read_text(), Loader=yaml.BaseLoader
     )
-    step = next(step for step in workflow["jobs"]["assemble"]["steps"] if step.get("id") == "hooks")
 
-    assert (step["uses"], step["with"]) == ("$/cooled-prek", {"args": "install-hooks"})
+    assert "install-hooks" not in str(workflow["jobs"]["assemble"]["steps"])
 
 
 def test_cooled_prek_action_passes_each_argument(tmp_path: Path, action_scripts: Path) -> None: