#1524 Fix query issue with matching (ChildOf, 0) when iterating compo…

…nent ids

distr/flecs.c

@@ -71407,6 +71407,7 @@ bool flecs_query_idsright(
         }
     }
 
+next:
     do {
         cur = op_ctx->cur = op_ctx->cur->first.next;
     } while (cur && !cur->cache.tables.count); /* Skip empty ids */
@@ -71415,6 +71416,12 @@ bool flecs_query_idsright(
         return false;
     }
 
+    if (cur->id == ecs_pair(EcsChildOf, 0)) {
+        /* Skip the special (ChildOf, 0) entry for root entities, as 0 is
+         * not a valid target and could be matched by (ChildOf, *) */
+        goto next;
+    }
+
     flecs_query_set_vars(op, cur->id, ctx);
 
     if (op->field_index != -1) {

src/query/engine/eval.c

@@ -627,6 +627,7 @@ bool flecs_query_idsright(
         }
     }
 
+next:
     do {
         cur = op_ctx->cur = op_ctx->cur->first.next;
     } while (cur && !cur->cache.tables.count); /* Skip empty ids */
@@ -635,6 +636,12 @@ bool flecs_query_idsright(
         return false;
     }
 
+    if (cur->id == ecs_pair(EcsChildOf, 0)) {
+        /* Skip the special (ChildOf, 0) entry for root entities, as 0 is
+         * not a valid target and could be matched by (ChildOf, *) */
+        goto next;
+    }
+
     flecs_query_set_vars(op, cur->id, ctx);
 
     if (op->field_index != -1) {

test/query/project.json

@@ -559,6 +559,8 @@
                 "2_any_src",
                 "2_any_src_w_pair",
                 "1_any_src_w_pair_tgt_var",
+                "1_any_src_w_pair_tgt_var_2",
+                "1_any_src_w_pair_tgt_var_childof",
                 "1_any_src_w_pair_rel_var",
                 "1_any_src_w_pair_tgt_this",
                 "1_any_src_w_pair_rel_this",

test/query/src/Basic.c

@@ -3702,6 +3702,107 @@ void Basic_1_any_src_w_pair_tgt_var(void) {
     ecs_fini(world);
 }
 
+void Basic_1_any_src_w_pair_tgt_var_2(void) {
+    ecs_world_t *world = ecs_mini();
+
+    ECS_TAG(world, Rel);
+    ECS_TAG(world, Foo);
+
+    ecs_entity_t e1 = ecs_new(world);
+    ecs_entity_t e2 = ecs_new(world);
+    ecs_entity_t e3 = ecs_new(world);
+
+    ecs_entity_t tgt_a = ecs_new(world);
+    ecs_entity_t tgt_b = ecs_new(world);
+
+    ecs_add_pair(world, e1, Rel, tgt_a);
+    ecs_add_pair(world, e2, Rel, tgt_b);
+    ecs_add_pair(world, e3, Rel, tgt_b);
+    ecs_add(world, e3, Foo);
+
+    ecs_query_t *q = ecs_query(world, {
+        .expr = "Rel(_, $x)",
+        .cache_kind = cache_kind
+    });
+
+    test_assert(q != NULL);
+
+    int x_var = ecs_query_find_var(q, "x");
+    test_assert(x_var != -1);
+
+    ecs_iter_t it = ecs_query_iter(world, q);
+    test_bool(true, ecs_query_next(&it));
+    test_int(0, it.count);
+    test_uint(ecs_pair(Rel, tgt_b), ecs_field_id(&it, 0));
+    test_uint(tgt_b, ecs_iter_get_var(&it, x_var));
+
+    test_bool(true, ecs_query_next(&it));
+    test_int(0, it.count);
+    test_uint(ecs_pair(Rel, tgt_a), ecs_field_id(&it, 0));
+    test_uint(tgt_a, ecs_iter_get_var(&it, x_var));
+
+    test_bool(false, ecs_query_next(&it));
+
+    ecs_query_fini(q);
+
+    ecs_fini(world);
+}
+
+void Basic_1_any_src_w_pair_tgt_var_childof(void) {
+    ecs_world_t *world = ecs_mini();
+
+    ECS_TAG(world, Rel);
+    ECS_TAG(world, Foo);
+
+    ecs_entity_t e1 = ecs_new(world);
+    ecs_entity_t e2 = ecs_new(world);
+    ecs_entity_t e3 = ecs_new(world);
+
+    ecs_entity_t tgt_a = ecs_new(world);
+    ecs_entity_t tgt_b = ecs_new(world);
+
+    ecs_add_pair(world, e1, Rel, tgt_a);
+    ecs_add_pair(world, e2, Rel, tgt_b);
+    ecs_add_pair(world, e3, Rel, tgt_b);
+    ecs_add(world, e3, Foo);
+
+    ecs_query_t *q = ecs_query(world, {
+        .expr = "ChildOf(_, $x)",
+        .cache_kind = cache_kind
+    });
+
+    test_assert(q != NULL);
+
+    int x_var = ecs_query_find_var(q, "x");
+    test_assert(x_var != -1);
+
+    ecs_iter_t it = ecs_query_iter(world, q);
+    test_bool(true, ecs_query_next(&it));
+    test_int(0, it.count);
+    test_uint(ecs_pair(EcsChildOf, EcsFlecs), ecs_field_id(&it, 0));
+    test_uint(EcsFlecs, ecs_iter_get_var(&it, x_var));
+    test_uint(EcsWildcard, ecs_field_src(&it, 0));
+
+    test_bool(true, ecs_query_next(&it));
+    ecs_entity_t internals = ecs_lookup(world, "flecs.core.internals");
+    test_int(0, it.count);
+    test_uint(ecs_pair(EcsChildOf, internals), ecs_field_id(&it, 0));
+    test_uint(internals, ecs_iter_get_var(&it, x_var));
+    test_uint(EcsWildcard, ecs_field_src(&it, 0));
+
+    test_bool(true, ecs_query_next(&it));
+    test_int(0, it.count);
+    test_uint(ecs_pair(EcsChildOf, EcsFlecsCore), ecs_field_id(&it, 0));
+    test_uint(EcsFlecsCore, ecs_iter_get_var(&it, x_var));
+    test_uint(EcsWildcard, ecs_field_src(&it, 0));
+
+    test_bool(false, ecs_query_next(&it));
+
+    ecs_query_fini(q);
+
+    ecs_fini(world);
+}
+
 void Basic_1_any_src_w_pair_rel_var(void) {
     ecs_world_t *world = ecs_mini();
 

test/query/src/Variables.c

@@ -11560,4 +11560,3 @@ void Variables_second_invalid_var_name_and_id(void) {
 
     ecs_fini(world);
 }
-

test/query/src/main.c

@@ -542,6 +542,8 @@ void Basic_1_any_src_w_pair(void);
 void Basic_2_any_src(void);
 void Basic_2_any_src_w_pair(void);
 void Basic_1_any_src_w_pair_tgt_var(void);
+void Basic_1_any_src_w_pair_tgt_var_2(void);
+void Basic_1_any_src_w_pair_tgt_var_childof(void);
 void Basic_1_any_src_w_pair_rel_var(void);
 void Basic_1_any_src_w_pair_tgt_this(void);
 void Basic_1_any_src_w_pair_rel_this(void);
@@ -4260,6 +4262,14 @@ bake_test_case Basic_testcases[] = {
         "1_any_src_w_pair_tgt_var",
         Basic_1_any_src_w_pair_tgt_var
     },
+    {
+        "1_any_src_w_pair_tgt_var_2",
+        Basic_1_any_src_w_pair_tgt_var_2
+    },
+    {
+        "1_any_src_w_pair_tgt_var_childof",
+        Basic_1_any_src_w_pair_tgt_var_childof
+    },
     {
         "1_any_src_w_pair_rel_var",
         Basic_1_any_src_w_pair_rel_var
@@ -10626,7 +10636,7 @@ static bake_test_suite suites[] = {
         "Basic",
         Basic_setup,
         NULL,
-        234,
+        236,
         Basic_testcases,
         1,
         Basic_params