python 3.9+: use removeprefix

asottile · asottile · commit 08478ec176b7 · 2023-12-09T16:04:25.000-05:00
diff --git a/pre_commit/languages/python.py b/pre_commit/languages/python.py
@@ -65,7 +65,7 @@ def _find_by_py_launcher(
         version: str,
 ) -> str | None:  # pragma: no cover (windows only)
     if version.startswith('python'):
-        num = version[len('python'):]
+        num = version.removeprefix('python')
         cmd = ('py', f'-{num}', '-c', 'import sys; print(sys.executable)')
         env = dict(os.environ, PYTHONIOENCODING='UTF-8')
         try:
@@ -124,7 +124,7 @@ def _sys_executable_matches(version: str) -> bool:
         return False
 
     try:
-        info = tuple(int(p) for p in version[len('python'):].split('.'))
+        info = tuple(int(p) for p in version.removeprefix('python').split('.'))
     except ValueError:
         return False
 
diff --git a/pre_commit/languages/rust.py b/pre_commit/languages/rust.py
@@ -134,7 +134,7 @@ def install_environment(
 
     packages_to_install: set[tuple[str, ...]] = {('--path', '.')}
     for cli_dep in cli_deps:
-        cli_dep = cli_dep[len('cli:'):]
+        cli_dep = cli_dep.removeprefix('cli:')
         package, _, crate_version = cli_dep.partition(':')
         if crate_version != '':
             packages_to_install.add((package, '--version', crate_version))
diff --git a/tests/commands/install_uninstall_test.py b/tests/commands/install_uninstall_test.py
@@ -349,8 +349,9 @@ def test_install_existing_hooks_no_overwrite(tempdir_factory, store):
         # We should run both the legacy and pre-commit hooks
         ret, output = _get_commit_output(tempdir_factory)
         assert ret == 0
-        assert output.startswith('legacy hook\n')
-        NORMAL_PRE_COMMIT_RUN.assert_matches(output[len('legacy hook\n'):])
+        legacy = 'legacy hook\n'
+        assert output.startswith(legacy)
+        NORMAL_PRE_COMMIT_RUN.assert_matches(output.removeprefix(legacy))
 
 
 def test_legacy_overwriting_legacy_hook(tempdir_factory, store):
@@ -375,8 +376,9 @@ def test_install_existing_hook_no_overwrite_idempotent(tempdir_factory, store):
         # We should run both the legacy and pre-commit hooks
         ret, output = _get_commit_output(tempdir_factory)
         assert ret == 0
-        assert output.startswith('legacy hook\n')
-        NORMAL_PRE_COMMIT_RUN.assert_matches(output[len('legacy hook\n'):])
+        legacy = 'legacy hook\n'
+        assert output.startswith(legacy)
+        NORMAL_PRE_COMMIT_RUN.assert_matches(output.removeprefix(legacy))
 
 
 def test_install_with_existing_non_utf8_script(tmpdir, store):
diff --git a/tests/store_test.py b/tests/store_test.py
@@ -185,7 +185,7 @@ def test_db_repo_name(store):
 
 def test_local_resources_reflects_reality():
     on_disk = {
-        res[len('empty_template_'):]
+        res.removeprefix('empty_template_')
         for res in os.listdir('pre_commit/resources')
         if res.startswith('empty_template_')
     }

Original file line number	Diff line number	Diff line change
`@@ -185,7 +185,7 @@ def test_db_repo_name(store):`
`185`	`185`
`186`	`186`	`def test_local_resources_reflects_reality():`
`187`	`187`	`on_disk = {`
`188`		`- res[len('empty_template_'):]`
	`188`	`+ res.removeprefix('empty_template_')`
`189`	`189`	`for res in os.listdir('pre_commit/resources')`
`190`	`190`	`if res.startswith('empty_template_')`
`191`	`191`	`}`