Re: [PATCH v19 1/2] refactor format_branch_comparison in preparation

"Harald Nordgren via GitGitGadget" [off-list ref] writes:

+static void format_branch_comparison(struct strbuf *sb,
+				     bool up_to_date,
+				     int ours, int theirs,
+				     const char *branch_name,
+				     enum ahead_behind_flags abf,
+				     bool show_divergence_advice)
+{
+	if (up_to_date) {
 		strbuf_addf(sb,
 			_("Your branch is up to date with '%s'.\n"),
-			base);
+			branch_name);
 	} else if (abf == AHEAD_BEHIND_QUICK) {
 		strbuf_addf(sb,
 			    _("Your branch and '%s' refer to different commits.\n"),
-			    base);
+			    branch_name);
 		if (advice_enabled(ADVICE_STATUS_HINTS))
 			strbuf_addf(sb, _("  (use \"%s\" for details)\n"),
 				    "git status --ahead-behind");

OK.  We _could_, just like we moved the "upstream_gone" case to the
caller, move the "up to date" case to the caller as well, but this
reads well now.  And we do not need the (!ours && !theirs) case in
this if/else if/... cascade.  Very good.

+/*
+ * Return true when there is anything to report, otherwise false.
+ */
+int format_tracking_info(struct branch *branch, struct strbuf *sb,
+			 enum ahead_behind_flags abf,
+			 int show_divergence_advice)
+{
+	int ours, theirs, sti;
+	const char *full_base;
+	char *base;
+	int upstream_is_gone = 0;
+
+	sti = stat_tracking_info(branch, &ours, &theirs, &full_base, 0, abf);
+	if (sti < 0) {
+		if (!full_base)
+			return 0;
+		upstream_is_gone = 1;
+	}
+
+	base = refs_shorten_unambiguous_ref(get_main_ref_store(the_repository),
+					    full_base, 0);
+
+	if (upstream_is_gone) {
+		strbuf_addf(sb,
+			_("Your branch is based on '%s', but the upstream is gone.\n"),
+			base);
+		if (advice_enabled(ADVICE_STATUS_HINTS))
+			strbuf_addstr(sb,
+				_("  (use \"git branch --unset-upstream\" to fixup)\n"));
+	} else {
+		format_branch_comparison(sb, !sti, ours, theirs, base, abf, show_divergence_advice);
+	}
+
 	free(base);
 	return 1;
 }