checkout: tone down the "forked status" diagnostic messages

diff --git a/builtin-checkout.c b/builtin-checkout.c
index 59a0ef4ec9770af6d031abe959adc587c9538a89..1fc1e56bdf0faa3dc9c320a234dbb224f028a1b3 100644 (file)
--- a/builtin-checkout.c
+++ b/builtin-checkout.c
@@ -12,6 +12,7 @@
 #include "branch.h"
 #include "diff.h"
 #include "revision.h"
+#include "remote.h"
 
 static const char * const checkout_usage[] = {
        "git checkout [options] <branch>",
@@ -290,6 +291,99 @@ static int merge_working_tree(struct checkout_opts *opts,
        return 0;
 }
 
+static void adjust_to_tracking(struct branch_info *new, struct checkout_opts *opts)
+{
+       /*
+        * We have switched to a new branch; is it building on
+        * top of another branch, and if so does that other branch
+        * have changes we do not have yet?
+        */
+       char *base;
+       unsigned char sha1[20];
+       struct commit *ours, *theirs;
+       char symmetric[84];
+       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;
+
+       /*
+        * 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);
+       ours = new->commit;
+       if (!hashcmp(sha1, ours->object.sha1))
+               return; /* we are the same */
+
+       /* 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++;
+       }
+
+       if (!prefixcmp(base, "refs/remotes/")) {
+               remote_msg = " remote";
+               base += strlen("refs/remotes/");
+       } 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,
                                   struct branch_info *new)
@@ -332,6 +426,8 @@ static void update_refs_for_switch(struct checkout_opts *opts,
        }
        remove_branch_state();
        strbuf_release(&msg);
+       if (!opts->quiet && (new->path || !strcmp(new->name, "HEAD")))
+               adjust_to_tracking(new, opts);
 }
 
 static int switch_branches(struct checkout_opts *opts,
@@ -409,6 +505,7 @@ int cmd_checkout(int argc, const char **argv, const char *prefix)
                OPT_BOOLEAN( 0 , "track", &opts.track, "track"),
                OPT_BOOLEAN('f', NULL, &opts.force, "force"),
                OPT_BOOLEAN('m', NULL, &opts.merge, "merge"),
+               OPT_END(),
        };
 
        memset(&opts, 0, sizeof(opts));