index_has_changes(): avoid assuming operating on the_index

Modify index_has_changes() to take a struct istate* instead of just
operating on the_index.  This is only a partial conversion, though,
because we call do_diff_cache() which implicitly assumes work is to be
done on the_index.  Ongoing work is being done elsewhere to do the
remainder of the conversion, and thus is not duplicated here.  Instead,
a simple check is put in place until that work is complete.

Signed-off-by: Elijah Newren <newren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 7 insertions, 4 deletions

diff --git a/read-cache.c b/read-cache.c
index ba094fd..f333a51 100644
--- a/read-cache.c
+++ b/read-cache.c
@@ -1986,11 +1986,14 @@ int unmerged_index(const struct index_state *istate)
 	return 0;
 }
 
-int index_has_changes(struct strbuf *sb)
+int index_has_changes(const struct index_state *istate, struct strbuf *sb)
 {
 	struct object_id head;
 	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)) {
 		struct diff_options opt;
 
@@ -2008,12 +2011,12 @@ int index_has_changes(struct strbuf *sb)
 		diff_flush(&opt);
 		return opt.flags.has_changes != 0;
 	} else {
-		for (i = 0; sb && i < the_index.cache_nr; i++) {
+		for (i = 0; sb && i < istate->cache_nr; i++) {
 			if (i)
 				strbuf_addch(sb, ' ');
-			strbuf_addstr(sb, the_index.cache[i]->name);
+			strbuf_addstr(sb, istate->cache[i]->name);
 		}
-		return !!the_index.cache_nr;
+		return !!istate->cache_nr;
 	}
 }