Merge branch 'jn/merge-diff3-label'

* jn/merge-diff3-label:
  merge-recursive: add a label for ancestor
  cherry-pick, revert: add a label for ancestor
  revert: clarify label on conflict hunks
  compat: add mempcpy()
  checkout -m --conflict=diff3: add a label for ancestor
  merge_trees(): add ancestor label parameter for diff3-style output
  merge_file(): add comment explaining behavior wrt conflict style
  checkout --conflict=diff3: add a label for ancestor
  ll_merge(): add ancestor label parameter for diff3-style output
  merge-file --diff3: add a label for ancestor
  xdl_merge(): move file1 and file2 labels to xmparam structure
  xdl_merge(): add optional ancestor label to diff3-style output
  tests: document cherry-pick behavior in face of conflicts
  tests: document format of conflicts from checkout -m

Conflicts:
	builtin/revert.c

diff --cc builtin/revert.c
index 9a3c14c329713f16d14147b81a4b8031028a4f82,1ddfac15b55a1b0bed7c7e359cb952749225a4f2..778a56eb512edde3aac6c2a4d668cc73ab3d8460
--- 1/builtin/revert.c
--- 2/builtin/revert.c
+++ b/builtin/revert.c
@@@ -271,10 -281,11 +304,10 @@@ static int revert_or_cherry_pick(int ar
  {
        unsigned char head[20];
        struct commit *base, *next, *parent;
+       const char *base_label, *next_label;
        int i, index_fd, clean;
-       char *oneline, *reencoded_message = NULL;
-       const char *message, *encoding;
+       struct commit_message msg = { NULL, NULL, NULL, NULL, NULL };
 -
 -      char *defmsg = git_pathdup("MERGE_MSG");
 +      char *defmsg = NULL;
        struct merge_options o;
        struct tree *result, *next_tree, *base_tree, *head_tree;
        static struct lock_file index_lock;
@@@ -346,13 -348,6 +379,9 @@@
        else
                parent = commit->parents->item;
  
-       if (!(message = commit->buffer))
-               die ("Cannot get commit message for %s",
-                               sha1_to_hex(commit->object.sha1));
- 
 +      if (allow_ff && !hashcmp(parent->object.sha1, head))
 +              return fast_forward_to(commit->object.sha1, head);
 +
        if (parent && parse_commit(parent) < 0)
                die("%s: cannot parse parent commit %s",
                    me, sha1_to_hex(parent->object.sha1));
@@@ -368,26 -366,13 +401,15 @@@
        msg_fd = hold_lock_file_for_update(&msg_file, defmsg,
                                           LOCK_DIE_ON_ERROR);
  
-       encoding = get_encoding(message);
-       if (!encoding)
-               encoding = "UTF-8";
-       if (!git_commit_encoding)
-               git_commit_encoding = "UTF-8";
-       if ((reencoded_message = reencode_string(message,
-                                       git_commit_encoding, encoding)))
-               message = reencoded_message;
- 
-       oneline = get_oneline(message);
- 
 +      index_fd = hold_locked_index(&index_lock, 1);
 +
        if (action == REVERT) {
-               char *oneline_body = strchr(oneline, ' ');
- 
                base = commit;
+               base_label = msg.label;
                next = parent;
+               next_label = msg.parent_label;
                add_to_msg("Revert \"");
-               add_to_msg(oneline_body + 1);
+               add_to_msg(msg.subject);
                add_to_msg("\"\n\nThis reverts commit ");
                add_to_msg(sha1_to_hex(commit->object.sha1));
  

diff --cc git-compat-util.h
Simple merge