query: use actual table id for IsA matches in fixed traversal

distr/flecs.c

@@ -85722,10 +85722,10 @@ bool flecs_query_trav_fixed_src_up_fixed_second(
 
     /* Check if table has transitive relationship by traversing upwards */
     ecs_table_record_t *tr = NULL;
-    ecs_search_relation(ctx->world, table, 0, 
-        ecs_pair(trav, second), trav, EcsSelf|EcsUp, NULL, NULL, &tr);
+    const int32_t index = ecs_search_relation(ctx->world, table, 0,
+        ecs_pair(trav, second), trav, EcsSelf| EcsUp, NULL, NULL, &tr);
 
-    if (!tr) {
+    if (index == -1 || !tr) {
         if (op->match_flags & EcsTermReflexive) {
             return flecs_query_trav_fixed_src_reflexive(op, ctx,
                 &range, trav, second);
@@ -85734,7 +85734,17 @@ bool flecs_query_trav_fixed_src_up_fixed_second(
         }
     }
 
-    flecs_query_set_trav_match(op, tr, trav, second, ctx);
+    ecs_id_t matched = ecs_pair(trav, second);
+    if (trav == EcsIsA) {
+        matched = table->type.array[index];
+    }
+
+    if (op->field_index != -1) {
+        ecs_iter_t *it = ctx->it;
+        it->ids [op->field_index] = matched;
+        flecs_query_it_set_tr(it, op->field_index, tr);
+    }
+    flecs_query_set_vars(op, matched, ctx);
     return true;
 }
 

docs/Docs.md

@@ -7,7 +7,7 @@
 - [Getting Started with Unreal Engine](https://github.com/PreyK/Unreal-Minimum-Viable-Flecs)
 - [Unreal-Flecs (Unreal Engine Flecs plugin)](https://github.com/Reddy-dev/Unreal-Flecs)
 - [Godot-flecs-sample (example)](https://github.com/paulfigiel/godot-flecs-sample)
-- [Flecs-Godot (GDExtension)](https://github.com/VoxInteractive/Godot-Flecs)
+- [Stagehand (GDExtension)](https://github.com/VerdantInteractive/Stagehand)
 - [Godot-turbo (engine module)](https://github.com/callmefloof/godot-turbo/) ([demo project](https://github.com/callmefloof/godot_turbo_demo_projects))
 - [Getting Started with Raylib](https://github.com/kranzky/raylib-flecs-starter-kit)
 - [Getting Started with SDL3, ImGui, Sqlite](https://github.com/ilyas-taouaou/CodotakuCMakeRepo) ([video](https://www.youtube.com/watch?v=T32B7nf6B-8))

src/query/engine/eval_trav.c

@@ -96,10 +96,10 @@ bool flecs_query_trav_fixed_src_up_fixed_second(
 
     /* Check if table has transitive relationship by traversing upwards */
     ecs_table_record_t *tr = NULL;
-    ecs_search_relation(ctx->world, table, 0, 
-        ecs_pair(trav, second), trav, EcsSelf|EcsUp, NULL, NULL, &tr);
+    const int32_t index = ecs_search_relation(ctx->world, table, 0,
+        ecs_pair(trav, second), trav, EcsSelf| EcsUp, NULL, NULL, &tr);
 
-    if (!tr) {
+    if (index == -1 || !tr) {
         if (op->match_flags & EcsTermReflexive) {
             return flecs_query_trav_fixed_src_reflexive(op, ctx,
                 &range, trav, second);
@@ -108,7 +108,17 @@ bool flecs_query_trav_fixed_src_up_fixed_second(
         }
     }
 
-    flecs_query_set_trav_match(op, tr, trav, second, ctx);
+    ecs_id_t matched = ecs_pair(trav, second);
+    if (trav == EcsIsA) {
+        matched = table->type.array[index];
+    }
+
+    if (op->field_index != -1) {
+        ecs_iter_t *it = ctx->it;
+        it->ids [op->field_index] = matched;
+        flecs_query_it_set_tr(it, op->field_index, tr);
+    }
+    flecs_query_set_vars(op, matched, ctx);
     return true;
 }
 

test/query/project.json

@@ -1690,7 +1690,8 @@
                 "this_or_w_self_up_childof",
                 "this_or_w_self_up_childof_2",
                 "this_or_w_self_up_childof_w_tag",
-                "this_written_or_w_self_up_childof"
+                "this_written_or_w_self_up_childof",
+                "this_written_up_isa_trav_id_n_lvl"
             ]
         }, {
             "id": "Cascade",

test/query/src/Traversal.c

@@ -13160,3 +13160,49 @@ void Traversal_this_written_or_w_self_up_childof(void) {
 
     ecs_fini(world);
 }
+
+void Traversal_this_written_up_isa_trav_id_n_lvl(void) {
+    ecs_world_t *world = ecs_mini();
+
+    ECS_COMPONENT(world, Position);
+    ecs_add_pair(world, ecs_id(Position), EcsOnInstantiate, EcsInherit);
+
+    /* Setup: instance --(IsA)--> troll --(IsA)--> enemy
+     * Position is on troll and inherited by instance.
+     * Querying (IsA, enemy) on this should match instance and report
+     * the field ID as (IsA, troll) — the actual pair in the archetype —
+     * not (IsA, enemy) which was incorrectly reconstructed from arguments
+     * before the fix in flecs_query_trav_fixed_src_up_fixed_second. */
+    ecs_entity_t enemy = ecs_new_w_id(world, EcsPrefab);
+    ecs_entity_t troll = ecs_new_w_id(world, EcsPrefab);
+    ecs_add_pair(world, troll, EcsIsA, enemy);
+    ecs_set(world, troll, Position, {10, 20});
+
+    ecs_entity_t instance = ecs_new_w_pair(world, EcsIsA, troll);
+
+    ecs_query_t *q = ecs_query(world, {
+        .terms = {
+            { ecs_id(Position) },             /* constrains 'this' to tables with Position */
+            { .id = ecs_pair(EcsIsA, enemy) } /* transitive IsA check */
+        },
+        .cache_kind = cache_kind
+    });
+
+    test_assert(q != NULL);
+
+    ecs_iter_t it = ecs_query_iter(world, q);
+    test_bool(true, ecs_query_next(&it));
+    test_int(1, it.count);
+    test_uint(instance, it.entities[0]);
+    test_uint(ecs_id(Position), ecs_field_id(&it, 0));
+    test_uint(troll, ecs_field_src(&it, 0));
+    /* The field ID for the (IsA, enemy) term must be the actual pair stored
+     * in the instance's archetype: (IsA, troll), not the query target. */
+    test_uint(ecs_pair(EcsIsA, troll), ecs_field_id(&it, 1));
+
+    test_bool(false, ecs_query_next(&it));
+
+    ecs_query_fini(q);
+
+    ecs_fini(world);
+}