From 390b8bd922d3a4f5b185030c6c58802457de6c1e Mon Sep 17 00:00:00 2001
From: dweiller <4678790+dweiller@users.noreplay.github.com>
Date: Sun, 12 Jun 2022 22:43:57 +1000
Subject: [PATCH] ecs: fix appendUndefined() off-by-one error

---
 ecs/src/entities.zig | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/ecs/src/entities.zig b/ecs/src/entities.zig
index 3c169bcc..8bd21bbc 100644
--- a/ecs/src/entities.zig
+++ b/ecs/src/entities.zig
@@ -97,8 +97,9 @@ pub const ArchetypeStorage = struct {
     pub fn appendUndefined(storage: *ArchetypeStorage, gpa: Allocator) !u32 {
         try storage.ensureUnusedCapacity(gpa, 1);
         assert(storage.len < storage.capacity);
+        const row_index = storage.len;
         storage.len += 1;
-        return storage.len;
+        return row_index;
     }
 
     pub fn append(storage: *ArchetypeStorage, gpa: Allocator, row: anytype) !u32 {