Merge branch 'js/merge-edit-option'

* js/merge-edit-option:
  Teach merge the '[-e|--edit]' option

Conflicts:
	builtin/merge.c

diff --cc builtin/merge.c
index 7d593097dea987e580d1e79f010faf23c1f98fb0,a8dbf4a32f09a1377eb489459837e5a07e36f490..dffd5ec1245865259fd4e72cc304286a1a5b4633
--- 1/builtin/merge.c
--- 2/builtin/merge.c
+++ b/builtin/merge.c
@@@ -861,15 -852,39 +863,39 @@@ static void read_merge_msg(struct strbu
                die_errno(_("Could not read from '%s'"), git_path("MERGE_MSG"));
  }
  
- static void run_prepare_commit_msg(void)
+ static void write_merge_state(void);
+ static void abort_commit(const char *err_msg)
  {
-       write_merge_msg();
+       if (err_msg)
+               error("%s", err_msg);
+       fprintf(stderr,
+               _("Not committing merge; use 'git commit' to complete the merge.\n"));
+       write_merge_state();
+       exit(1);
+ }
+ 
+ static void prepare_to_commit(void)
+ {
+       struct strbuf msg = STRBUF_INIT;
+       strbuf_addbuf(&msg, &merge_msg);
+       strbuf_addch(&msg, '\n');
+       write_merge_msg(&msg);
        run_hook(get_index_file(), "prepare-commit-msg",
                 git_path("MERGE_MSG"), "merge", NULL, NULL);
-       read_merge_msg();
+       if (option_edit) {
+               if (launch_editor(git_path("MERGE_MSG"), NULL, NULL))
+                       abort_commit(NULL);
+       }
+       read_merge_msg(&msg);
+       stripspace(&msg, option_edit);
+       if (!msg.len)
+               abort_commit(_("Empty commit message."));
+       strbuf_release(&merge_msg);
+       strbuf_addbuf(&merge_msg, &msg);
+       strbuf_release(&msg);
  }
  
 -static int merge_trivial(void)
 +static int merge_trivial(struct commit *head)
  {
        unsigned char result_tree[20], result_commit[20];
        struct commit_list *parent = xmalloc(sizeof(*parent));
@@@ -880,9 -895,9 +906,9 @@@
        parent->next = xmalloc(sizeof(*parent->next));
        parent->next->item = remoteheads->item;
        parent->next->next = NULL;
-       run_prepare_commit_msg();
+       prepare_to_commit();
        commit_tree(merge_msg.buf, result_tree, parent, result_commit, NULL);
 -      finish(result_commit, "In-index merge");
 +      finish(head, result_commit, "In-index merge");
        drop_save();
        return 0;
  }
@@@ -909,12 -923,12 +935,12 @@@ static int finish_automerge(struct comm
                for (j = remoteheads; j; j = j->next)
                        pptr = &commit_list_insert(j->item, pptr)->next;
        }
-       free_commit_list(remoteheads);
        strbuf_addch(&merge_msg, '\n');
-       run_prepare_commit_msg();
+       prepare_to_commit();
+       free_commit_list(remoteheads);
        commit_tree(merge_msg.buf, result_tree, parents, result_commit, NULL);
        strbuf_addf(&buf, "Merge made by the '%s' strategy.", wt_strategy);
 -      finish(result_commit, buf.buf);
 +      finish(head, result_commit, buf.buf);
        strbuf_release(&buf);
        drop_save();
        return 0;
@@@ -1422,34 -1464,9 +1478,9 @@@ int cmd_merge(int argc, const char **ar
        }
  
        if (squash)
 -              finish(NULL, NULL);
 +              finish(head_commit, NULL, NULL);
-       else {
-               int fd;
-               struct commit_list *j;
- 
-               for (j = remoteheads; j; j = j->next)
-                       strbuf_addf(&buf, "%s\n",
-                               sha1_to_hex(j->item->object.sha1));
-               fd = open(git_path("MERGE_HEAD"), O_WRONLY | O_CREAT, 0666);
-               if (fd < 0)
-                       die_errno(_("Could not open '%s' for writing"),
-                                 git_path("MERGE_HEAD"));
-               if (write_in_full(fd, buf.buf, buf.len) != buf.len)
-                       die_errno(_("Could not write to '%s'"), git_path("MERGE_HEAD"));
-               close(fd);
-               strbuf_addch(&merge_msg, '\n');
-               write_merge_msg();
-               fd = open(git_path("MERGE_MODE"), O_WRONLY | O_CREAT | O_TRUNC, 0666);
-               if (fd < 0)
-                       die_errno(_("Could not open '%s' for writing"),
-                                 git_path("MERGE_MODE"));
-               strbuf_reset(&buf);
-               if (!allow_fast_forward)
-                       strbuf_addf(&buf, "no-ff");
-               if (write_in_full(fd, buf.buf, buf.len) != buf.len)
-                       die_errno(_("Could not write to '%s'"), git_path("MERGE_MODE"));
-               close(fd);
-       }
+       else
+               write_merge_state();
  
        if (merge_was_ok) {
                fprintf(stderr, _("Automatic merge went well; "