filter-repo: add new --replace-message option

Like --replace-text, add an option --replace-message which replaces text
in commit/tag message bodies, so that users can easily replace text
without constructing a --message-callback.

Signed-off-by: Gwyneth Morgan <gwymor@tilde.club>
Signed-off-by: Elijah Newren <newren@gmail.com>

Documentation/git-filter-repo.txt

@@ -181,6 +181,11 @@ Renaming of refs (see also --refname-callback)
 Filtering of commit messages (see also --message-callback)
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
+--replace-message <expressions_file>::
+	A file with expressions that, if found in commit or tag
+	messages, will be replaced. This file uses the same syntax as
+	--replace-text.
+
 --preserve-commit-hashes::
 	By default, since commits are rewritten and thus gain new
 	hashes, references to old commit hashes in commit messages are
@@ -896,6 +901,26 @@ YYYY-MM-DD.  In the expressions file, there are a few things to note:
 
 See also the `--blob-callback` from <<CALLBACKS>>.
 
+Updating commit/tag messages
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+If you want to modify commit or tag messages, you can do so with the
+same syntax as `--replace-text`, explained above.  For example, with a
+file named expressions.txt containing
+
+--------------------------------------------------
+foo==>bar
+--------------------------------------------------
+
+then running
+--------------------------------------------------
+git filter-repo --replace-message expressions.txt
+--------------------------------------------------
+
+will replace `foo` in commit or tag messages with `bar`.
+
+See also the `--message-callback` from <<CALLBACKS>>.
+
 Refname based filtering
 ~~~~~~~~~~~~~~~~~~~~~~~
 

git-filter-repo

@@ -1843,6 +1843,10 @@ EXAMPLES
 
     messages = parser.add_argument_group(title=_("Filtering of commit messages "
                                                "(see also --message-callback)"))
+    messages.add_argument('--replace-message', metavar='EXPRESSIONS_FILE',
+        help=_("A file with expressions that, if found in commit messages, "
+               "will be replaced. This file uses the same syntax as "
+               "--replace-text."))
     messages.add_argument('--preserve-commit-hashes', action='store_true',
         help=_("By default, since commits are rewritten and thus gain new "
                "hashes, references to old commit hashes in commit messages "
@@ -2189,6 +2193,8 @@ EXAMPLES
       args.mailmap = MailmapInfo(args.mailmap)
     if args.replace_text:
       args.replace_text = FilteringOptions.get_replace_text(args.replace_text)
+    if args.replace_message:
+      args.replace_message = FilteringOptions.get_replace_text(args.replace_message)
     if args.strip_blobs_with_ids:
       with open(args.strip_blobs_with_ids, 'br') as f:
         args.strip_blobs_with_ids = set(f.read().split())
@@ -3374,6 +3380,11 @@ class RepoFilter(object):
     if not self._args.preserve_commit_hashes:
       commit.message = self._hash_re.sub(self._translate_commit_hash,
                                          commit.message)
+    if self._args.replace_message:
+      for literal, replacement in self._args.replace_message['literals']:
+        commit.message = commit.message.replace(literal, replacement)
+      for regex,   replacement in self._args.replace_message['regexes']:
+        commit.message = regex.sub(replacement, commit.message)
     if self._message_callback:
       commit.message = self._message_callback(commit.message)
 
@@ -3474,6 +3485,11 @@ class RepoFilter(object):
 
   def _tweak_tag(self, tag):
     # Tweak the tag message according to callbacks
+    if self._args.replace_message:
+      for literal, replacement in self._args.replace_message['literals']:
+        tag.message = tag.message.replace(literal, replacement)
+      for regex,   replacement in self._args.replace_message['regexes']:
+        tag.message = regex.sub(replacement, tag.message)
     if self._message_callback:
       tag.message = self._message_callback(tag.message)
 

t/t9390-filter-repo.sh

@@ -39,6 +39,7 @@ filter_testcase basic basic-filename --invert-paths --path-glob 't*en*'
 filter_testcase basic basic-numbers  --invert-paths --path-regex 'f.*e.*e'
 filter_testcase basic basic-mailmap  --mailmap ../t9390/sample-mailmap
 filter_testcase basic basic-replace  --replace-text ../t9390/sample-replace
+filter_testcase basic basic-message  --replace-message ../t9390/sample-message
 filter_testcase empty empty-keepme   --path keepme
 filter_testcase empty more-empty-keepme --path keepme --prune-empty=always \
 		                                   --prune-degenerate=always

t/t9390/basic-message

@@ -0,0 +1,78 @@
+feature done
+blob
+mark :1
+data 8
+initial
+
+reset refs/heads/B
+commit refs/heads/B
+mark :2
+author Little O. Me <me@little.net> 1535228562 -0700
+committer Little O. Me <me@little.net> 1535228562 -0700
+data 9
+Modified
+M 100644 :1 filename
+M 100644 :1 ten
+M 100644 :1 twenty
+
+blob
+mark :3
+data 11
+twenty-mod
+
+commit refs/heads/B
+mark :4
+author Little 'ol Me <me@laptop.(none)> 1535229544 -0700
+committer Little 'ol Me <me@laptop.(none)> 1535229544 -0700
+data 18
+add the number 20
+from :2
+M 100644 :3 twenty
+
+blob
+mark :5
+data 8
+ten-mod
+
+commit refs/heads/A
+mark :6
+author Little O. Me <me@machine52.little.net> 1535229523 -0700
+committer Little O. Me <me@machine52.little.net> 1535229523 -0700
+data 8
+add ten
+from :2
+M 100644 :5 ten
+
+commit refs/heads/master
+mark :7
+author Lit.e Me <me@fire.com> 1535229559 -0700
+committer Lit.e Me <me@fire.com> 1535229580 -0700
+data 24
+Merge branch 'A' into B
+from :4
+merge :6
+M 100644 :5 ten
+
+blob
+mark :8
+data 6
+final
+
+commit refs/heads/master
+mark :9
+author Little Me <me@bigcompany.com> 1535229601 -0700
+committer Little Me <me@bigcompany.com> 1535229601 -0700
+data 9
+whatever
+from :7
+M 100644 :8 filename
+M 100644 :8 ten
+M 100644 :8 twenty
+
+tag v1.0
+from :9
+tagger Little John <second@merry.men> 1535229618 -0700
+data 15
+version one :)
+
+done

t/t9390/sample-message

@@ -0,0 +1,4 @@
+Initial==>Modified
+regex:tw.nty==>the number 20
+v1.0==>version one!
+regex:!$==> :)