merge: split reduce_parents() out of collect_parents()

The latter does two separate things:

 - Parse the list of commits on the command line, and formulate the
   list of commits to be merged (including the current HEAD);

 - Compute the list of parents to be recorded in the resulting merge
   commit.

Split the latter into a separate helper function, so that we can
later supply the list commits to be merged from a different source
(namely, FETCH_HEAD).

Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/builtin/merge.c b/builtin/merge.c
index d2e36e2..054f052 100644 (file)
--- a/builtin/merge.c
+++ b/builtin/merge.c
@@ -1044,23 +1044,11 @@ static int default_edit_option(void)
                st_stdin.st_mode == st_stdout.st_mode);
 }
 
-static struct commit_list *collect_parents(struct commit *head_commit,
-                                          int *head_subsumed,
-                                          int argc, const char **argv)
+static struct commit_list *reduce_parents(struct commit *head_commit,
+                                         int *head_subsumed,
+                                         struct commit_list *remoteheads)
 {
-       int i;
-       struct commit_list *remoteheads = NULL, *parents, *next;
-       struct commit_list **remotes = &remoteheads;
-
-       if (head_commit)
-               remotes = &commit_list_insert(head_commit, remotes)->next;
-       for (i = 0; i < argc; i++) {
-               struct commit *commit = get_merge_parent(argv[i]);
-               if (!commit)
-                       help_unknown_ref(argv[i], "merge",
-                                        "not something we can merge");
-               remotes = &commit_list_insert(commit, remotes)->next;
-       }
+       struct commit_list *parents, *next, **remotes = &remoteheads;
 
        /*
         * Is the current HEAD reachable from another commit being
@@ -1088,6 +1076,27 @@ static struct commit_list *collect_parents(struct commit *head_commit,
        return remoteheads;
 }
 
+static struct commit_list *collect_parents(struct commit *head_commit,
+                                          int *head_subsumed,
+                                          int argc, const char **argv)
+{
+       int i;
+       struct commit_list *remoteheads = NULL;
+       struct commit_list **remotes = &remoteheads;
+
+       if (head_commit)
+               remotes = &commit_list_insert(head_commit, remotes)->next;
+       for (i = 0; i < argc; i++) {
+               struct commit *commit = get_merge_parent(argv[i]);
+               if (!commit)
+                       help_unknown_ref(argv[i], "merge",
+                                        "not something we can merge");
+               remotes = &commit_list_insert(commit, remotes)->next;
+       }
+
+       return reduce_parents(head_commit, head_subsumed, remoteheads);
+}
+
 int cmd_merge(int argc, const char **argv, const char *prefix)
 {
        unsigned char result_tree[20];