fix(hook): catch an option and its value passed as one argument

README.md

@@ -172,6 +172,9 @@ repos:
 
 **NOTE:** when using as a pre-commit hook, `input` is supplied automatically (with the current commit's message).
 
+**NOTE:** pre-commit passes each item in `args` as a single argument, so an option and its value go in separate items,
+like `[--scopes, api]` (or `[--scopes=api]`), not `[--scopes api]`.
+
 ## Development
 
 `conventional-pre-commit` comes with a [VS Code devcontainer](https://code.visualstudio.com/learn/develop-cloud/containers)

conventional_pre_commit/hook.py

@@ -44,6 +44,14 @@ def main(argv=[]):
 
     try:
         args = parser.parse_args(argv)
+        # pre-commit passes each item in `args` as one argument, so `--scopes api` arrives
+        # as a single string. argparse doesn't see an option in it and takes it as a type.
+        for commit_type in args.types:
+            if commit_type.startswith("-"):
+                parser.error(
+                    f'"{commit_type}" looks like an option and its value in one argument. '
+                    + "Pass them separately, e.g. [--scopes, api] or [--scopes=api]."
+                )
     except SystemExit:
         return RESULT_FAIL
 

tests/test_hook.py

@@ -78,6 +78,19 @@ def test_main_success__conventional_with_scope(cmd, conventional_commit_with_sco
     assert result == RESULT_SUCCESS
 
 
+def test_main_fail__option_and_value_in_one_arg(conventional_commit_with_scope_path, capsys):
+    result = main(["--force-scope", "--scopes api", conventional_commit_with_scope_path])
+
+    assert result == RESULT_FAIL
+    assert '"--scopes api" looks like an option and its value in one argument' in capsys.readouterr().err
+
+
+def test_main_success__option_and_value_with_equals(conventional_commit_with_scope_path):
+    result = main(["--force-scope", "--scopes=scope", conventional_commit_with_scope_path])
+
+    assert result == RESULT_SUCCESS
+
+
 def test_main_success__fixup_commit(fixup_commit_path):
     result = main([fixup_commit_path])