fix: disable pre-commit.ci checks if using dependabot pre-commit (#758)

* fix: disable pre-commit.ci checks if using dependabot pre-commit

Signed-off-by: Henry Schreiner <henryfs@princeton.edu>

* docs: also mention in guide

Signed-off-by: Henry Schreiner <henryfs@princeton.edu>

---------

Signed-off-by: Henry Schreiner <henryfs@princeton.edu>

Author: henryiii

docs/pages/guides/style.md

@@ -108,6 +108,24 @@ ci:
 
 The frequencies can be "weekly" (the default), "monthly", and "quarterly".
 
+If you prefer, you can use Dependabot, which will also auto-update, though it
+doesn't run the checks. The config looks like this:
+
+```yaml
+version: 2
+updates:
+  - package-ecosystem: "pre-commit"
+    directory: "/"
+    schedule:
+      interval: "monthly"
+    groups:
+      pre-commit:
+        patterns:
+          - "*"
+    cooldown:
+      default-days: 7
+```
+
 ## Format
 
 {% rr PC110 %} [Black](https://black.readthedocs.io/en/latest/) is a popular

src/sp_repo_review/checks/precommit.py

@@ -204,7 +204,7 @@ class PC901(PreCommit):
     "Custom pre-commit CI update message"
 
     @staticmethod
-    def check(precommit: dict[str, Any]) -> bool:
+    def check(precommit: dict[str, Any], dependabot: dict[str, Any]) -> bool | None:  # type: ignore[override]
         """
         Should have something like this in `.pre-commit-config.yaml`:
 
@@ -213,6 +213,11 @@ def check(precommit: dict[str, Any]) -> bool:
           autoupdate_commit_msg: 'chore(deps): update pre-commit hooks'
         ```
         """
+        if any(
+            ecosystem.get("package-ecosystem", "") == "github-actions"
+            for ecosystem in dependabot.get("updates", [])
+        ):
+            return None
 
         return "autoupdate_commit_msg" in precommit.get("ci", {})
 
@@ -221,7 +226,7 @@ class PC902(PreCommit):
     "Custom pre-commit CI autofix message"
 
     @staticmethod
-    def check(precommit: dict[str, Any]) -> bool:
+    def check(precommit: dict[str, Any], dependabot: dict[str, Any]) -> bool | None:  # type: ignore[override]
         """
         Should have something like this in `.pre-commit-config.yaml`:
 
@@ -230,6 +235,11 @@ def check(precommit: dict[str, Any]) -> bool:
           autofix_commit_msg: "style: pre-commit fixes"
         ```
         """
+        if any(
+            ecosystem.get("package-ecosystem", "") == "github-actions"
+            for ecosystem in dependabot.get("updates", [])
+        ):
+            return None
 
         return "autofix_commit_msg" in precommit.get("ci", {})
 
@@ -238,7 +248,7 @@ class PC903(PreCommit):
     "Specified pre-commit CI schedule"
 
     @staticmethod
-    def check(precommit: dict[str, Any]) -> bool:
+    def check(precommit: dict[str, Any], dependabot: dict[str, Any]) -> bool | None:  # type: ignore[override]
         """
         Should set some schedule: `weekly` (default), `monthly`, or `quarterly`.
 
@@ -247,6 +257,11 @@ def check(precommit: dict[str, Any]) -> bool:
           autoupdate_schedule: "monthly"
         ```
         """
+        if any(
+            ecosystem.get("package-ecosystem", "") == "github-actions"
+            for ecosystem in dependabot.get("updates", [])
+        ):
+            return None
 
         return "autoupdate_schedule" in precommit.get("ci", {})
 

tests/test_precommit.py

@@ -243,14 +243,22 @@ def test_pc901():
         ci:
           autoupdate_commit_msg: 'chore: update pre-commit hooks'
     """)
-    assert compute_check("PC901", precommit=precommit).result
+    assert compute_check("PC901", precommit=precommit, dependabot={}).result
+
+
+def test_pc901_not_needed():
+    dependabot = yaml.safe_load("""
+        updates:
+          - package-ecosystem: "github-actions"
+    """)
+    assert compute_check("PC901", precommit={}, dependabot=dependabot).result is None
 
 
 def test_pc901_no_msg():
     precommit = yaml.safe_load("""
     repos:
     """)
-    res = compute_check("PC901", precommit=precommit)
+    res = compute_check("PC901", precommit=precommit, dependabot={})
     assert not res.result
     assert "autoupdate_commit_msg" in res.err_msg
 
@@ -260,36 +268,52 @@ def test_pc902():
         ci:
           autofix_commit_msg: 'style: pre-commit fixes'
     """)
-    assert compute_check("PC902", precommit=precommit).result
+    assert compute_check("PC902", precommit=precommit, dependabot={}).result
 
 
 def test_pc902_no_msg():
     precommit = yaml.safe_load("""
     repos:
     """)
-    res = compute_check("PC902", precommit=precommit)
+    res = compute_check("PC902", precommit=precommit, dependabot={})
     assert not res.result
     assert "autofix_commit_msg" in res.err_msg
 
 
+def test_pc902_not_needed():
+    dependabot = yaml.safe_load("""
+        updates:
+          - package-ecosystem: "github-actions"
+    """)
+    assert compute_check("PC902", precommit={}, dependabot=dependabot).result is None
+
+
 def test_pc903():
     precommit = yaml.safe_load("""
         ci:
           autoupdate_schedule: "monthly"
 
     """)
-    assert compute_check("PC903", precommit=precommit).result
+    assert compute_check("PC903", precommit=precommit, dependabot={}).result
 
 
 def test_pc903_no_msg():
     precommit = yaml.safe_load("""
     repos:
     """)
-    res = compute_check("PC903", precommit=precommit)
+    res = compute_check("PC903", precommit=precommit, dependabot={})
     assert not res.result
     assert "autoupdate_schedule" in res.err_msg
 
 
+def test_pc903_not_needed():
+    dependabot = yaml.safe_load("""
+        updates:
+          - package-ecosystem: "github-actions"
+    """)
+    assert compute_check("PC903", precommit={}, dependabot=dependabot).result is None
+
+
 def test_repo_review_checks_skips_with_lefthook_only(tmp_path: Path) -> None:
     """PreCommit checks should be omitted if only lefthook.yml is present.