1 files changed, 9 insertions, 6 deletions
diff --git a/src/lua_event_bridge.zig b/src/lua_event_bridge.zig
index f6d67e0..c4acb1d 100644
--- a/src/lua_event_bridge.zig
+++ b/src/lua_event_bridge.zig
@@ -797,9 +797,11 @@ test "Lua-defined component renders lines through the bridged vtable" {
     try testing.expectEqual(@as(usize, 2), lines.len);
     try testing.expectEqualStrings("hello", lines[0]);
     try testing.expectEqualStrings("world", lines[1]);
-    // firstLineChanged is cache-derived: first render dirties from 0.
-    try testing.expectEqual(@as(?usize, 0), chosen.?.firstLineChanged());
-    // A second identical render reports no change.
+    // firstLineChanged is cache-derived and is the LIVE signal: after a render
+    // the cache is clean, so it reports null (the first-render diff index 0 is
+    // retained internally as bookkeeping only).
+    try testing.expectEqual(@as(?usize, null), chosen.?.firstLineChanged());
+    // A second identical render still reports no change.
     _ = try chosen.?.render(80, testing.allocator);
     try testing.expectEqual(@as(?usize, null), chosen.?.firstLineChanged());
 }
@@ -1258,10 +1260,11 @@ test "bridged firstLineChanged is cache-derived: append stays near the tail" {
     try bridge.attachBus(&bus);
     const chosen = bus.fire("tool", null, .{ .tool = .{} }).?;
 
-    // First render: 2 lines, dirty from 0.
+    // First render: 2 lines. After the render the cache is clean, so the live
+    // signal is null (the first-render diff index 0 is internal bookkeeping).
     _ = try chosen.render(80, testing.allocator);
-    try testing.expectEqual(@as(?usize, 0), chosen.firstLineChanged());
-    // No change: null.
+    try testing.expectEqual(@as(?usize, null), chosen.firstLineChanged());
+    // No change: still null.
     _ = try chosen.render(80, testing.allocator);
     try testing.expectEqual(@as(?usize, null), chosen.firstLineChanged());