[PATCH] fix same sized delta logic

[PATCH] fix same sized delta logic

[Nicolas Pitre]

The code favoring shallower deltas when size is equal was triggered 
only when previous delta was also cached.  There should be no relation 
between cached deltas and same sized deltas.

Signed-off-by: Nicolas Pitre <nico@cam.org>
---
diff --git a/builtin-pack-objects.c b/builtin-pack-objects.c
index 9b3ef94..12509fa 100644
--- a/builtin-pack-objects.c
+++ b/builtin-pack-objects.c
@@ -1389,21 +1389,25 @@ static int try_delta(struct unpacked *trg, struct unpacked *src,
 	if (!delta_buf)
 		return 0;
 
-	if (trg_entry->delta_data) {
+	if (trg_entry->delta) {
 		/* Prefer only shallower same-sized deltas. */
 		if (delta_size == trg_entry->delta_size &&
 		    src->depth + 1 >= trg->depth) {
 			free(delta_buf);
 			return 0;
 		}
-		delta_cache_size -= trg_entry->delta_size;
-		free(trg_entry->delta_data);
-		trg_entry->delta_data = NULL;
 	}
+
 	trg_entry->delta = src_entry;
 	trg_entry->delta_size = delta_size;
 	trg->depth = src->depth + 1;
 
+	if (trg_entry->delta_data) {
+		delta_cache_size -= trg_entry->delta_size;
+		free(trg_entry->delta_data);
+		trg_entry->delta_data = NULL;
+	}
+
 	if (delta_cacheable(src_size, trg_size, delta_size)) {
 		trg_entry->delta_data = xrealloc(delta_buf, delta_size);
 		delta_cache_size += trg_entry->delta_size;