Check whether a pre-commit hook is used as a part of is_used heuris… (#813)

nathanjmcdougall · web-flow · commit 91e5716aea21 · 2025-06-28T15:15:05.000+12:00
* Check whether a pre-commit hook is used as a part of `is_used` heuristics

* Fix pre-commit schema violation in pre-commit integration test

* Try reading pre-commit config last in `is_used` to improve performance

* Fix undefined FileDecodeError - change to FileConfigError
diff --git a/src/usethis/_tool/base.py b/src/usethis/_tool/base.py
@@ -106,8 +106,9 @@ def is_used(self) -> bool:
 
         Three heuristics are used by default:
         1. Whether any of the tool's characteristic dependencies are in the project.
-        2. Whether any of the tool's managed files are in the project.
-        3. Whether any of the tool's managed config file sections are present.
+        2. Whether any of the tool's characteristic pre-commit hooks are in the project.
+        3. Whether any of the tool's managed files are in the project.
+        4. Whether any of the tool's managed config file sections are present.
         """
         decode_err_by_name: dict[str, FileConfigError] = {}
         _is_used = False
@@ -128,6 +129,13 @@ def is_used(self) -> bool:
             except FileConfigError as err:
                 decode_err_by_name[err.name] = err
 
+        # Do this last since the YAML parsing is expensive.
+        if not _is_used:
+            try:
+                _is_used = self.is_pre_commit_config_present()
+            except FileConfigError as err:
+                decode_err_by_name[err.name] = err
+
         for name, decode_err in decode_err_by_name.items():
             warn_print(decode_err)
             warn_print(
diff --git a/tests/usethis/_tool/test_base.py b/tests/usethis/_tool/test_base.py
@@ -3,6 +3,7 @@
 
 import pytest
 
+from usethis._config_file import files_manager
 from usethis._console import box_print
 from usethis._integrations.file.pyproject_toml.io_ import PyprojectTOMLManager
 from usethis._integrations.file.setup_cfg.io_ import SetupCFGManager
@@ -404,6 +405,23 @@ def preferred_file_manager(self) -> KeyValueFileManager:
                 "\n⚠ Assuming 'setup.cfg' contains no evidence of my_tool being used.\n"
             )
 
+        def test_pre_commit_config(self, uv_init_dir: Path):
+            # Arrange
+            tool = MyTool()
+            with change_cwd(uv_init_dir), files_manager():
+                # Create a pre-commit config file
+                (uv_init_dir / ".pre-commit-config.yaml").write_text("""\
+repos:
+  - repo: local
+    hooks:
+      - id: deptry
+""")
+
+                # Act
+                result = tool.is_used()
+            # Assert
+            assert result
+
     class TestIsDeclaredAsDep:
         def test_dev_deps(self, uv_init_dir: Path):
             # Arrange
