checkout: tone down the "forked status" diagnostic messages

When checking out a branch that is behind or forked from a
branch you are building on top of, we used to show full
left-right log but if you already _know_ you have long history
since you forked, it is a bit too much.

This tones down the message quite a bit, by only showing the
number of commits each side has since they diverged.  Also the
message is not shown at all under --quiet.

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

diff --git a/builtin-checkout.c b/builtin-checkout.c
index 5291f72a370729d72bb990a3cd7db1c2672ca37d..1fc1e56bdf0faa3dc9c320a234dbb224f028a1b3 100644 (file)
--- a/builtin-checkout.c
+++ b/builtin-checkout.c
@@ -301,64 +301,88 @@ static void adjust_to_tracking(struct branch_info *new, struct checkout_opts *op
        char *base;
        unsigned char sha1[20];
        struct commit *ours, *theirs;
-       const char *msgfmt;
        char symmetric[84];
-       int show_log;
+       struct rev_info revs;
+       const char *rev_argv[10];
+       int rev_argc;
+       int num_ours, num_theirs;
+       const char *remote_msg;
        struct branch *branch = branch_get(NULL);
 
+       /*
+        * Nothing to report unless we are marked to build on top of
+        * somebody else.
+        */
        if (!branch || !branch->merge)
                return;
 
-       base = branch->merge[0]->dst;
-
-       ours = new->commit;
-
-       sprintf(symmetric, "%s", sha1_to_hex(ours->object.sha1));
-
        /*
-        * Ok, it is tracking base; is it ahead of us?
+        * If what we used to build on no longer exists, there is
+        * nothing to report.
         */
+       base = branch->merge[0]->dst;
        if (!resolve_ref(base, sha1, 1, NULL))
                return;
-       theirs = lookup_commit(sha1);
-
-       sprintf(symmetric + 40, "...%s", sha1_to_hex(sha1));
 
+       theirs = lookup_commit(sha1);
+       ours = new->commit;
        if (!hashcmp(sha1, ours->object.sha1))
                return; /* we are the same */
 
-       show_log = 1;
-       if (in_merge_bases(theirs, &ours, 1)) {
-               msgfmt = "You are ahead of the tracked branch '%s'\n";
-               show_log = 0;
+       /* Run "rev-list --left-right ours...theirs" internally... */
+       rev_argc = 0;
+       rev_argv[rev_argc++] = NULL;
+       rev_argv[rev_argc++] = "--left-right";
+       rev_argv[rev_argc++] = symmetric;
+       rev_argv[rev_argc++] = "--";
+       rev_argv[rev_argc] = NULL;
+
+       strcpy(symmetric, sha1_to_hex(ours->object.sha1));
+       strcpy(symmetric + 40, "...");
+       strcpy(symmetric + 43, sha1_to_hex(theirs->object.sha1));
+
+       init_revisions(&revs, NULL);
+       setup_revisions(rev_argc, rev_argv, &revs, NULL);
+       prepare_revision_walk(&revs);
+
+       /* ... and count the commits on each side. */
+       num_ours = 0;
+       num_theirs = 0;
+       while (1) {
+               struct commit *c = get_revision(&revs);
+               if (!c)
+                       break;
+               if (c->object.flags & SYMMETRIC_LEFT)
+                       num_ours++;
+               else
+                       num_theirs++;
        }
-       else if (in_merge_bases(ours, &theirs, 1))
-               msgfmt = "Your branch can be fast-forwarded to the tracked branch '%s'\n";
-       else
-               msgfmt = "Both your branch and the tracked branch '%s' have own changes, you would eventually need to merge\n";
 
-       if (!prefixcmp(base, "refs/remotes/"))
+       if (!prefixcmp(base, "refs/remotes/")) {
+               remote_msg = " remote";
                base += strlen("refs/remotes/");
-       fprintf(stderr, msgfmt, base);
-
-       if (show_log) {
-               const char *args[32];
-               int ac;
-
-               ac = 0;
-               args[ac++] = "log";
-               args[ac++] = "--pretty=oneline";
-               args[ac++] = "--abbrev-commit";
-               args[ac++] = "--left-right";
-               args[ac++] = "--boundary";
-               args[ac++] = symmetric;
-               args[ac++] = "--";
-               args[ac] = NULL;
-
-               run_command_v_opt(args, RUN_GIT_CMD);
+       } else {
+               remote_msg = "";
        }
-}
 
+       if (!num_theirs)
+               printf("Your branch is ahead of the tracked%s branch '%s' "
+                      "by %d commit%s.\n",
+                      remote_msg, base,
+                      num_ours, (num_ours == 1) ? "" : "s");
+       else if (!num_ours)
+               printf("Your branch is behind of the tracked%s branch '%s' "
+                      "by %d commit%s,\n"
+                      "and can be fast-forwarded.\n",
+                      remote_msg, base,
+                      num_theirs, (num_theirs == 1) ? "" : "s");
+       else
+               printf("Your branch and the tracked%s branch '%s' "
+                      "have diverged,\nand respectively "
+                      "have %d and %d different commit(s) each.\n",
+                      remote_msg, base,
+                      num_ours, num_theirs);
+}
 
 static void update_refs_for_switch(struct checkout_opts *opts,
                                   struct branch_info *old,
@@ -402,7 +426,7 @@ static void update_refs_for_switch(struct checkout_opts *opts,
        }
        remove_branch_state();
        strbuf_release(&msg);
-       if (new->path || !strcmp(new->name, "HEAD"))
+       if (!opts->quiet && (new->path || !strcmp(new->name, "HEAD")))
                adjust_to_tracking(new, opts);
 }