#1549 Fix issue with command queue that contains both recycld and old id

Author: SanderMertens

distr/flecs.c

@@ -16201,6 +16201,7 @@ ecs_cmd_t* flecs_cmd_new_batched(
 
     int32_t cur = ecs_vec_count(cmds);
     ecs_cmd_t *cmd = flecs_cmd_new(stage);
+    bool is_new = false;
     if (entry) {
         if (entry->first == -1) {
             /* Existing but invalidated entry */
@@ -16209,16 +16210,25 @@ ecs_cmd_t* flecs_cmd_new_batched(
         } else {
             int32_t last = entry->last;
             ecs_cmd_t *arr = ecs_vec_first_t(cmds, ecs_cmd_t);
-            ecs_assert(arr[last].entity == e, ECS_INTERNAL_ERROR, NULL);
-            ecs_cmd_t *last_op = &arr[last];
-            last_op->next_for_entity = cur;
-            if (last == entry->first) {
-                /* Flip sign bit so flush logic can tell which command
-                 * is the first for an entity */
-                last_op->next_for_entity *= -1;
+            if (arr[last].entity == e) {
+                ecs_cmd_t *last_op = &arr[last];
+                last_op->next_for_entity = cur;
+                if (last == entry->first) {
+                    /* Flip sign bit so flush logic can tell which command
+                    * is the first for an entity */
+                    last_op->next_for_entity *= -1;
+                }
+            } else {
+                /* Entity with different version was in the same queue. Discard
+                 * the old entry and create a new one. */
+                is_new = true;
             }
         }
     } else {
+        is_new = true;
+    }
+
+    if (is_new) {
         cmd->entry = entry = flecs_sparse_ensure_fast_t(
             &stage->cmd->entries, ecs_cmd_entry_t, e);
         entry->first = cur;

src/stage.c

@@ -42,6 +42,7 @@ ecs_cmd_t* flecs_cmd_new_batched(
 
     int32_t cur = ecs_vec_count(cmds);
     ecs_cmd_t *cmd = flecs_cmd_new(stage);
+    bool is_new = false;
     if (entry) {
         if (entry->first == -1) {
             /* Existing but invalidated entry */
@@ -50,16 +51,25 @@ ecs_cmd_t* flecs_cmd_new_batched(
         } else {
             int32_t last = entry->last;
             ecs_cmd_t *arr = ecs_vec_first_t(cmds, ecs_cmd_t);
-            ecs_assert(arr[last].entity == e, ECS_INTERNAL_ERROR, NULL);
-            ecs_cmd_t *last_op = &arr[last];
-            last_op->next_for_entity = cur;
-            if (last == entry->first) {
-                /* Flip sign bit so flush logic can tell which command
-                 * is the first for an entity */
-                last_op->next_for_entity *= -1;
+            if (arr[last].entity == e) {
+                ecs_cmd_t *last_op = &arr[last];
+                last_op->next_for_entity = cur;
+                if (last == entry->first) {
+                    /* Flip sign bit so flush logic can tell which command
+                    * is the first for an entity */
+                    last_op->next_for_entity *= -1;
+                }
+            } else {
+                /* Entity with different version was in the same queue. Discard
+                 * the old entry and create a new one. */
+                is_new = true;
             }
         }
     } else {
+        is_new = true;
+    }
+
+    if (is_new) {
         cmd->entry = entry = flecs_sparse_ensure_fast_t(
             &stage->cmd->entries, ecs_cmd_entry_t, e);
         entry->first = cur;

test/core/project.json

@@ -2284,7 +2284,8 @@
                 "redefine_named_in_threaded_app",
                 "batched_cmd_w_component_init",
                 "deep_command_nesting",
-                "ensure_from_2_stages"
+                "ensure_from_2_stages",
+                "batch_w_old_and_recycled_id"
             ]
         }, {
             "id": "SingleThreadStaging",

test/core/src/Commands.c

@@ -4749,3 +4749,50 @@ void Commands_ensure_from_2_stages(void) {
 
     ecs_fini(world);
 }
+
+static ECS_COMPONENT_DECLARE(Velocity);
+
+static void remove_velocity(ecs_iter_t *it) {
+    ecs_remove(it->world, it->entities[0], Velocity);
+}
+
+void Commands_batch_w_old_and_recycled_id(void) {
+    ecs_world_t *world = ecs_mini();
+
+    ECS_COMPONENT(world, Position);
+    ECS_COMPONENT_DEFINE(world, Velocity);
+
+    ecs_observer(world, {
+        .query.terms = {{ ecs_id(Position) }},
+        .events = { EcsOnRemove },
+        .callback = remove_velocity
+    });
+
+    ecs_entity_t parent = ecs_new(world);
+    ecs_entity_t child = ecs_new_w_pair(world, EcsChildOf, parent);
+
+    ecs_entity_t grandchild = ecs_new(world);
+    ecs_add_pair(world, grandchild, EcsChildOf, child);
+    ecs_add(world, grandchild, Position);
+
+    ecs_defer_begin(world);
+    ecs_defer_suspend(world);
+    ecs_delete(world, child);
+    ecs_entity_t child_2 = ecs_new_w_pair(world, EcsChildOf, parent);
+    ecs_defer_resume(world);
+    ecs_entity_t e = ecs_new(world);
+    ecs_add(world, e, Position);
+
+    test_assert(!ecs_has(world, e, Position));
+    ecs_defer_end(world);
+
+    test_assert(ecs_is_alive(world, parent));
+    test_assert(!ecs_is_alive(world, child));
+    test_assert(ecs_is_alive(world, child_2));
+    test_assert(!ecs_is_alive(world, grandchild));
+    test_assert(ecs_is_alive(world, e));
+    test_assert(ecs_has_pair(world, child_2, EcsChildOf, parent));
+    test_assert(ecs_has(world, e, Position));
+
+    ecs_fini(world);
+}

test/core/src/main.c

@@ -2204,6 +2204,7 @@ void Commands_redefine_named_in_threaded_app(void);
 void Commands_batched_cmd_w_component_init(void);
 void Commands_deep_command_nesting(void);
 void Commands_ensure_from_2_stages(void);
+void Commands_batch_w_old_and_recycled_id(void);
 
 // Testsuite 'SingleThreadStaging'
 void SingleThreadStaging_setup(void);
@@ -10915,6 +10916,10 @@ bake_test_case Commands_testcases[] = {
     {
         "ensure_from_2_stages",
         Commands_ensure_from_2_stages
+    },
+    {
+        "batch_w_old_and_recycled_id",
+        Commands_batch_w_old_and_recycled_id
     }
 };
 
@@ -11795,7 +11800,7 @@ static bake_test_suite suites[] = {
         "Commands",
         NULL,
         NULL,
-        155,
+        156,
         Commands_testcases
     },
     {