fix: go lint parallel run

.pre-commit-hooks.yaml

@@ -43,6 +43,8 @@
     Requires Go 1.23 or newer on PATH.
   entry: polymath_code_standard go
   types_or: [go, go-mod, go-sum]
+  # golangci-lint holds a file lock per run, so all files go to one process.
+  require_serial: true
 
 - <<: *python-hook
   id: polymath-javascript

CHANGELOG.md

@@ -3,6 +3,13 @@
 All notable changes to this project are documented in this file.
 Releases follow semantic versioning as described in [DEVELOPING.md](./DEVELOPING.md).
 
+## 2.6.1
+
+### Fixed
+
+- `polymath-go` no longer fails with "parallel golangci-lint is running" on commits with many Go files.
+  The hook runs as a single process, and golangci-lint tolerates other instances such as an editor's.
+
 ## 2.6.0
 
 New hooks for Go and the web stack.

README.md

@@ -36,7 +36,7 @@ Use only the hooks that apply to your project.
 ---
 repos:
   - repo: https://github.com/polymathrobotics/polymath_code_standard
-    rev: v2.6.0
+    rev: v2.6.1
     hooks:
       # File hygiene for all staged files
       - id: polymath-general

polymath_code_standard/checkers/go/golangci.yml

@@ -3,6 +3,8 @@ version: '2'
 run:
   # Report paths relative to the module root the hook runs from.
   relative-path-mode: wd
+  # Tolerate another golangci-lint instance, such as an editor's.
+  allow-parallel-runners: true
 formatters:
   enable:
     - gofumpt

pyproject.toml

@@ -4,7 +4,7 @@ build-backend = "setuptools.build_meta"
 
 [project]
 name = "polymath-code-standard"
-version = "2.6.0"
+version = "2.6.1"
 description = "Polymath Code Standard pre-commit hooks"
 requires-python = ">=3.10"
 dependencies = [

tests/test_go.py

@@ -15,6 +15,7 @@
 from pathlib import Path
 
 import pytest
+import yaml
 
 from polymath_code_standard import runner
 from polymath_code_standard.checker import Result
@@ -92,6 +93,18 @@ def test_package_dirs_collapses_to_distinct_directories():
     assert go_checker.package_dirs(relative) == ['.', './pkg', './pkg/sub']
 
 
+def test_hook_runs_as_a_single_process():
+    """pre-commit passes every staged file to one process, since golangci-lint locks per run."""
+    hooks = yaml.safe_load((_PROJECT_ROOT / '.pre-commit-hooks.yaml').read_text())
+    go_hook = next(h for h in hooks if h['id'] == 'polymath-go')
+    assert go_hook['require_serial'] is True
+
+
+def test_bundled_config_allows_parallel_runners():
+    config = yaml.safe_load((go_checker.CONFIG_DIR / 'golangci.yml').read_text())
+    assert config['run']['allow-parallel-runners'] is True
+
+
 def test_file_without_go_mod_fails(tmp_path, monkeypatch):
     monkeypatch.setattr(go_checker.shutil, 'which', lambda _: '/usr/bin/go')
     stray = tmp_path / 'stray.go'