merge: fix misleading pre-merge check documentation

diff --git a/read-cache.c b/read-cache.c
index f333a517f7d674e95b42ccab9808f276438e64b9..639c1fffa0635e8829ad76d74407b06447e42b1f 100644 (file)
--- a/read-cache.c
+++ b/read-cache.c
@@ -1986,22 +1986,26 @@ int unmerged_index(const struct index_state *istate)
        return 0;
 }
 
-int index_has_changes(const struct index_state *istate, struct strbuf *sb)
+int index_has_changes(const struct index_state *istate,
+                     struct tree *tree,
+                     struct strbuf *sb)
 {
-       struct object_id head;
+       struct object_id cmp;
        int i;
 
        if (istate != &the_index) {
                BUG("index_has_changes cannot yet accept istate != &the_index; do_diff_cache needs updating first.");
        }
-       if (!get_oid_tree("HEAD", &head)) {
+       if (tree)
+               cmp = tree->object.oid;
+       if (tree || !get_oid_tree("HEAD", &cmp)) {
                struct diff_options opt;
 
                diff_setup(&opt);
                opt.flags.exit_with_status = 1;
                if (!sb)
                        opt.flags.quick = 1;
-               do_diff_cache(&head, &opt);
+               do_diff_cache(&cmp, &opt);
                diffcore_std(&opt);
                for (i = 0; sb && i < diff_queued_diff.nr; i++) {
                        if (i)