do not segfault if make_cache_entry failed

Signed-off-by: Dmitry Potapov <dpotapov@gmail.com>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

builtin-apply.c

@@ -2586,6 +2586,8 @@ static void build_fake_ancestor(struct patch *list, const char *filename)
 			sha1_ptr = sha1;
 
 		ce = make_cache_entry(patch->old_mode, sha1_ptr, name, 0, 0);
+		if (!ce)
+			die("make_cache_entry failed for path '%s'", name);
 		if (add_index_entry(&result, ce, ADD_CACHE_OK_TO_ADD))
 			die ("Could not add %s to temporary index", name);
 	}

builtin-checkout.c

@@ -206,6 +206,8 @@ static int checkout_merged(int pos, struct checkout *state)
 	ce = make_cache_entry(create_ce_mode(active_cache[pos+1]->ce_mode),
 			      sha1,
 			      path, 2, 0);
+	if (!ce)
+		die("make_cache_entry failed for path '%s'", path);
 	status = checkout_entry(ce, state, NULL);
 	return status;
 }

builtin-reset.c

@@ -121,6 +121,9 @@ static void update_index_from_diff(struct diff_queue_struct *q,
 			struct cache_entry *ce;
 			ce = make_cache_entry(one->mode, one->sha1, one->path,
 				0, 0);
+			if (!ce)
+				die("make_cache_entry failed for path '%s'",
+				    one->path);
 			add_cache_entry(ce, ADD_CACHE_OK_TO_ADD |
 				ADD_CACHE_OK_TO_REPLACE);
 		} else