Split long commit message to multiple lines to respect the maximun of 80 characters per line imposed by Lantian

gitdch

@@ -7,6 +7,7 @@ import logging
 import os
 import re
 import sys
+import textwrap
 
 import git
 
@@ -69,6 +70,18 @@ parser.add_argument(
     help='Generated Debian changelog output path (default: stdout)',
 )
 
+parser.add_argument(
+    '-A',
+    '--append',
+    action='store_true',
+    dest='append',
+    help=(
+        'Append mode: if the output changelog file already exists, append '
+        'generated changelog lines at the begining of the file (optional, '
+        'default: overwriting the file)'
+    )
+)
+
 parser.add_argument(
     '-n',
     '--package-name',
@@ -136,6 +149,17 @@ parser.add_argument(
     help='Specify an optional Markdown release notes output path'
 )
 
+parser.add_argument(
+    '--revision',
+    type=str,
+    dest='revision',
+    help=(
+        'Specify the revision to use to generate the changelog (see '
+        'git-rev-parse for viable options, optional, default: generate the '
+        'changelog with all commits of the current branch) '
+    ),
+    default=None
+)
 
 options = parser.parse_args()
 
@@ -213,7 +237,7 @@ version = (
     )
 )
 messages = []
-for commit in repo.iter_commits():
+for commit in repo.iter_commits(rev=options.revision):
     if version_commit is None:
         version_commit = commit
     log.debug('Commit %s', commit)
@@ -244,11 +268,17 @@ for version in versions:
         )
     )
 
-    # pylint: disable=consider-using-f-string
+    for message in version['messages']:
-    changelog_lines.extend([
+        for idx, line in enumerate(
-      '  * {0}\n'.format(message)
+            textwrap.wrap(message, 76, break_long_words=True)
-      for message in version['messages']
+        ):
-    ])
+            # pylint: disable=consider-using-f-string
+            changelog_lines.append(
+                '{0}{1}\n'.format(
+                    '  * ' if not idx else '    ',
+                    line
+                )
+            )
 
     # pylint: disable=consider-using-f-string
     changelog_lines.append(
@@ -266,6 +296,10 @@ for version in versions:
 
 if options.output:
     log.info('Write generated Debian changelog in file %s', options.output)
+    if options.append and os.path.exists(options.output):
+        with open(options.output, 'r', encoding='utf8') as fd:
+            changelog_lines += [""]
+            changelog_lines += fd.readlines()
     with open(options.output, 'w', encoding='utf8') as fd:
         fd.writelines(changelog_lines)
 else: