format-patch: introduce --base=auto option

[thirdparty/git.git] / builtin / log.c

diff --git a/builtin/log.c b/builtin/log.c
index c9ee333932daf10bf0f03716369b0b5bcec95ebe..9033bc7c54619bd6c59521b8f39f30e6b2333887 100644 (file)
--- a/builtin/log.c
+++ b/builtin/log.c
@@ -1199,9 +1199,33 @@ static struct commit *get_base_commit(const char *base_commit,
        struct commit **rev;
        int i = 0, rev_nr = 0;
 
-       base = lookup_commit_reference_by_name(base_commit);
-       if (!base)
-               die(_("Unknown commit %s"), base_commit);
+       if (!strcmp(base_commit, "auto")) {
+               struct branch *curr_branch = branch_get(NULL);
+               const char *upstream = branch_get_upstream(curr_branch, NULL);
+               if (upstream) {
+                       struct commit_list *base_list;
+                       struct commit *commit;
+                       unsigned char sha1[20];
+
+                       if (get_sha1(upstream, sha1))
+                               die(_("Failed to resolve '%s' as a valid ref."), upstream);
+                       commit = lookup_commit_or_die(sha1, "upstream base");
+                       base_list = get_merge_bases_many(commit, total, list);
+                       /* There should be one and only one merge base. */
+                       if (!base_list || base_list->next)
+                               die(_("Could not find exact merge base."));
+                       base = base_list->item;
+                       free_commit_list(base_list);
+               } else {
+                       die(_("Failed to get upstream, if you want to record base commit automatically,\n"
+                             "please use git branch --set-upstream-to to track a remote branch.\n"
+                             "Or you could specify base commit by --base=<base-commit-id> manually."));
+               }
+       } else {
+               base = lookup_commit_reference_by_name(base_commit);
+               if (!base)
+                       die(_("Unknown commit %s"), base_commit);
+       }
 
        ALLOC_ARRAY(rev, total);
        for (i = 0; i < total; i++)