insert-license hook: switching to --comment-style + more doc

README.md

@@ -21,13 +21,25 @@ Hooks that require Python dependencies, or specific to a language, have been ext
         -   id: remove-tabs
             args: [ --whitespaces-count, 2 ]  # defaults to: 4
         -   id: insert-license
-            files: \.py$
+            files: \.groovy$
             args:
             - --license-filepath
             - src/license_header.txt          # defaults to: LICENSE.txt
-            - --comment-prefix
+            - --comment-style
             - //                              # defaults to: #
 
+### insert-license
+
+For Java / Javascript / CSS, set `--comment-style /*| *| */`.
+
+In case you want to remove the comment headers introduced by the `insert-license` hook,
+e.g. because you want to change the wording of your `LICENSE.txt` and update the comments in your source files:
+
+1. temporarily add the `--remove-header` arg in your `.pre-commit-config.yaml`
+2. run the hook on all your files: `pre-commit run insert-license --all-files`
+3. remove the `--remove-header` arg and update your `LICENSE.txt`
+4. re-run the hook on all your files
+
 
 ## Other useful local hooks
 

pre_commit_hooks/insert_license.py

@@ -6,21 +6,26 @@ def main(argv=None):
     parser = argparse.ArgumentParser()
     parser.add_argument('filenames', nargs='*', help='filenames to check')
     parser.add_argument('--license-filepath', default='LICENSE.txt')
-    parser.add_argument('--comment-start', default='/*\n')
-    parser.add_argument('--comment-prefix', default=' *')
-    parser.add_argument('--comment-end', default='\n */')
+    parser.add_argument('--comment-style', default='#',
+                        help='Can be a single prefix or a triplet: <comment-sart>|<comment-prefix>|<comment-end>'
+                             'E.g.: /*| *| */')
     parser.add_argument('--detect-license-in-X-top-lines', type=int, default=5)
     parser.add_argument('--remove-header', action='store_true')
     args = parser.parse_args(argv)
 
+    if '|' in args.comment_style:
+        comment_start, comment_prefix, comment_end = args.comment_style.split('|')
+    else:
+        comment_start, comment_prefix, comment_end = None, args.comment_style, None
+
     with open(args.license_filepath) as license_file:
-        prefixed_license = ['{}{}{}'.format(args.comment_prefix, ' ' if line.strip() else '', line)
+        prefixed_license = ['{}{}{}'.format(comment_prefix, ' ' if line.strip() else '', line)
                             for line in license_file.readlines()]
     eol = '\r\n' if prefixed_license[0][-2:] == '\r\n' else '\n'
-    if args.comment_start:
-        prefixed_license = [args.comment_start] + prefixed_license
-    if args.comment_end:
-        prefixed_license = prefixed_license + [args.comment_end]
+    if comment_start:
+        prefixed_license = [comment_start+'\n'] + prefixed_license
+    if comment_end:
+        prefixed_license = prefixed_license + ['\n'+comment_end]
 
     changes_made = False
     for src_filepath in args.filenames:

tests/insert_license_test.py

@@ -18,11 +18,10 @@
     ),
 )
 def test_insert_license(src_file_path, comment_prefix, new_src_file_expected, tmpdir):
-    default_args = ['--comment-start', '', '--comment-end', '', '--comment-prefix']
     with chdir_to_test_resources():
         path = tmpdir.join('src_file_path')
         shutil.copy(src_file_path, path.strpath)
-        assert insert_license(default_args + [comment_prefix, path.strpath]) == (1 if new_src_file_expected else 0)
+        assert insert_license(['--comment-style', comment_prefix, path.strpath]) == (1 if new_src_file_expected else 0)
         if new_src_file_expected:
             with open(new_src_file_expected) as expected_content_file:
                 expected_content = expected_content_file.read()
@@ -56,7 +55,9 @@ def test_remove_license(src_file_path, is_python, new_src_file_expected, tmpdir)
         shutil.copy(src_file_path, path.strpath)
         argv = ['--remove-header', path.strpath]
         if is_python:
-            argv = ['--comment-start', '', '--comment-end', '', '--comment-prefix', '#'] + argv
+            argv = ['--comment-style', '#'] + argv
+        else:
+            argv = ['--comment-style', '/*| *| */'] + argv
         assert insert_license(argv) == (1 if new_src_file_expected else 0)
         if new_src_file_expected:
             with open(new_src_file_expected) as expected_content_file: