branch: drop non-commit error reporting

Remove the error "branch '%s' does not point at a commit" in
append_ref(), which reports branch refs which do not point to
commits.  Also remove the error "some refs could not be read" in
print_ref_list() which is triggered as a consequence of the first
error.

The purpose of these codepaths is not to diagnose and report a
repository corruption.  If we care about such a corruption, we
should report it from fsck instead, which we already do.

This also helps in a smooth port of branch.c to use ref-filter APIs
over the following patches. On the other hand, ref-filter ignores refs
which do not point at commits silently.

Based-on-patch-by: Jeff King <peff@peff.net>
Helped-by: Junio C Hamano <gitster@pobox.com>
Mentored-by: Christian Couder <christian.couder@gmail.com>
Mentored-by: Matthieu Moy <matthieu.moy@grenoble-inp.fr>
Signed-off-by: Karthik Nayak <karthik.188@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/branch.c

@@ -313,7 +313,6 @@ static char *resolve_symref(const char *src, const char *prefix)
 struct append_ref_cb {
 	struct ref_list *ref_list;
 	const char **pattern;
-	int ret;
 };
 
 static int match_patterns(const char **pattern, const char *refname)
@@ -370,10 +369,8 @@ static int append_ref(const char *refname, const struct object_id *oid, int flag
 	commit = NULL;
 	if (ref_list->verbose || ref_list->with_commit || merge_filter != NO_FILTER) {
 		commit = lookup_commit_reference_gently(oid->hash, 1);
-		if (!commit) {
-			cb->ret = error(_("branch '%s' does not point at a commit"), refname);
+		if (!commit)
 			return 0;
-		}
 
 		/* Filter with with_commit if specified */
 		if (!is_descendant_of(commit, ref_list->with_commit))
@@ -617,7 +614,7 @@ static int calc_maxwidth(struct ref_list *refs, int remote_bonus)
 	return max;
 }
 
-static int print_ref_list(int kinds, int detached, int verbose, int abbrev, struct commit_list *with_commit, const char **pattern)
+static void print_ref_list(int kinds, int detached, int verbose, int abbrev, struct commit_list *with_commit, const char **pattern)
 {
 	int i;
 	struct append_ref_cb cb;
@@ -642,7 +639,6 @@ static int print_ref_list(int kinds, int detached, int verbose, int abbrev, stru
 		init_revisions(&ref_list.revs, NULL);
 	cb.ref_list = &ref_list;
 	cb.pattern = pattern;
-	cb.ret = 0;
 	/*
 	 * First we obtain all regular branch refs and if the HEAD is
 	 * detached then we insert that ref to the end of the ref_fist
@@ -693,11 +689,6 @@ static int print_ref_list(int kinds, int detached, int verbose, int abbrev, stru
 			       abbrev, detached, remote_prefix);
 
 	free_ref_list(&ref_list);
-
-	if (cb.ret)
-		error(_("some refs could not be read"));
-
-	return cb.ret;
 }
 
 static void rename_branch(const char *oldname, const char *newname, int force)
@@ -913,15 +904,14 @@ int cmd_branch(int argc, const char **argv, const char *prefix)
 			die(_("branch name required"));
 		return delete_branches(argc, argv, delete > 1, kinds, quiet);
 	} else if (list) {
-		int ret;
 		/*  git branch --local also shows HEAD when it is detached */
 		if (kinds & REF_LOCAL_BRANCH)
 			kinds |= REF_DETACHED_HEAD;
-		ret = print_ref_list(kinds, detached, verbose, abbrev,
+		print_ref_list(kinds, detached, verbose, abbrev,
 					 with_commit, argv);
 		print_columns(&output, colopts, NULL);
 		string_list_clear(&output, 0);
-		return ret;
+		return 0;
 	}
 	else if (edit_description) {
 		const char *branch_name;