which() prefers the executable found in $PATH

which() kept looking after shutil.which found a name in $PATH, so a later
fallback path (e.g. '/usr/bin/git' in which('git', '/usr/bin/git'))
always replaced it.  Its docstring says $PATH comes first; stop at the
first match.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

wrolpi/cmd.py

@@ -41,6 +41,7 @@ def which(*possible_paths: str, warn: bool = False) -> Optional[Path]:
         if path and (path := Path(path).absolute()) and is_executable(path):
             # `path` was a name or relative path.
             found = path
+            break
 
     if not found and warn and not PYTEST and not DOCKERIZED:
         logger.warning(f'Cannot find executable {possible_paths[0]}')

wrolpi/test/test_cmd.py

@@ -26,6 +26,20 @@ def test_which(test_directory):
     assert cmd.which('asdf', str(foo)) == foo
 
 
+def test_which_prefers_path(test_directory, monkeypatch):
+    """A name found in $PATH wins over a fallback path, even when the fallback exists too."""
+    on_path, fallback = test_directory / 'bin', test_directory / 'fallback'
+    for directory in (on_path, fallback):
+        directory.mkdir()
+        (directory / 'tool').touch()
+        os.chmod(directory / 'tool', 0o777)
+    monkeypatch.setenv('PATH', str(on_path))
+
+    assert cmd.which('tool', str(fallback / 'tool')) == on_path / 'tool'
+    # The fallback is used when the name is not in $PATH.
+    assert cmd.which('missing', str(fallback / 'tool')) == fallback / 'tool'
+
+
 TEST_SCRIPT = '''#!/bin/sh
 echo stdout
 echo stderr >&2