doc hash-function-transition: clarify how older gits die on NewHash

diff --git a/remote.c b/remote.c
index a9b4853e65341b20688dea16ac31ab1606bc0234..c10d87c24615e9d6497b46a69a82a71d3c1735a6 100644 (file)
--- a/remote.c
+++ b/remote.c
@@ -2022,16 +2022,23 @@ int ref_newer(const struct object_id *new_oid, const struct object_id *old_oid)
 }
 
 /*
- * Compare a branch with its upstream, and save their differences (number
- * of commits) in *num_ours and *num_theirs. The name of the upstream branch
- * (or NULL if no upstream is defined) is returned via *upstream_name, if it
- * is not itself NULL.
+ * Lookup the upstream branch for the given branch and if present, optionally
+ * compute the commit ahead/behind values for the pair.
+ *
+ * If abf is AHEAD_BEHIND_FULL, compute the full ahead/behind and return the
+ * counts in *num_ours and *num_theirs.  If abf is AHEAD_BEHIND_QUICK, skip
+ * the (potentially expensive) a/b computation (*num_ours and *num_theirs are
+ * set to zero).
+ *
+ * The name of the upstream branch (or NULL if no upstream is defined) is
+ * returned via *upstream_name, if it is not itself NULL.
  *
  * Returns -1 if num_ours and num_theirs could not be filled in (e.g., no
- * upstream defined, or ref does not exist), 0 otherwise.
+ * upstream defined, or ref does not exist).  Returns 0 if the commits are
+ * identical.  Returns 1 if commits are different.
  */
 int stat_tracking_info(struct branch *branch, int *num_ours, int *num_theirs,
-                      const char **upstream_name)
+                      const char **upstream_name, enum ahead_behind_flags abf)
 {
        struct object_id oid;
        struct commit *ours, *theirs;
@@ -2059,11 +2066,15 @@ int stat_tracking_info(struct branch *branch, int *num_ours, int *num_theirs,
        if (!ours)
                return -1;
 
+       *num_theirs = *num_ours = 0;
+
        /* are we the same? */
-       if (theirs == ours) {
-               *num_theirs = *num_ours = 0;
+       if (theirs == ours)
                return 0;
-       }
+       if (abf == AHEAD_BEHIND_QUICK)
+               return 1;
+       if (abf != AHEAD_BEHIND_FULL)
+               BUG("stat_tracking_info: invalid abf '%d'", abf);
 
        /* Run "rev-list --left-right ours...theirs" internally... */
        argv_array_push(&argv, ""); /* ignored */
@@ -2079,8 +2090,6 @@ int stat_tracking_info(struct branch *branch, int *num_ours, int *num_theirs,
                die("revision walk setup failed");
 
        /* ... and count the commits on each side. */
-       *num_ours = 0;
-       *num_theirs = 0;
        while (1) {
                struct commit *c = get_revision(&revs);
                if (!c)
@@ -2096,20 +2105,22 @@ int stat_tracking_info(struct branch *branch, int *num_ours, int *num_theirs,
        clear_commit_marks(theirs, ALL_REV_FLAGS);
 
        argv_array_clear(&argv);
-       return 0;
+       return 1;
 }
 
 /*
  * Return true when there is anything to report, otherwise false.
  */
-int format_tracking_info(struct branch *branch, struct strbuf *sb)
+int format_tracking_info(struct branch *branch, struct strbuf *sb,
+                        enum ahead_behind_flags abf)
 {
-       int ours, theirs;
+       int ours, theirs, sti;
        const char *full_base;
        char *base;
        int upstream_is_gone = 0;
 
-       if (stat_tracking_info(branch, &ours, &theirs, &full_base) < 0) {
+       sti = stat_tracking_info(branch, &ours, &theirs, &full_base, abf);
+       if (sti < 0) {
                if (!full_base)
                        return 0;
                upstream_is_gone = 1;
@@ -2123,10 +2134,17 @@ int format_tracking_info(struct branch *branch, struct strbuf *sb)
                if (advice_status_hints)
                        strbuf_addstr(sb,
                                _("  (use \"git branch --unset-upstream\" to fixup)\n"));
-       } else if (!ours && !theirs) {
+       } else if (!sti) {
                strbuf_addf(sb,
                        _("Your branch is up to date with '%s'.\n"),
                        base);
+       } else if (abf == AHEAD_BEHIND_QUICK) {
+               strbuf_addf(sb,
+                           _("Your branch and '%s' refer to different commits.\n"),
+                           base);
+               if (advice_status_hints)
+                       strbuf_addf(sb, _("  (use \"%s\" for details)\n"),
+                                   "git status --ahead-behind");
        } else if (!theirs) {
                strbuf_addf(sb,
                        Q_("Your branch is ahead of '%s' by %d commit.\n",