From 5414ea59cfc35852cb68b94982c91ed1ec95d6cf Mon Sep 17 00:00:00 2001
From: Sander Mertens <sander.mertens8@gmail.com>
Date: Mon, 19 Aug 2024 17:59:00 -0700
Subject: [PATCH] Fix crash when serializing query plan for trivial query

---
 flecs.c                                  |  8 +++-
 src/addons/json/serialize_iter.c         |  8 +++-
 test/meta/project.json                   |  4 +-
 test/meta/src/SerializeQueryInfoToJson.c | 58 ++++++++++++++++++++++++
 test/meta/src/main.c                     | 12 ++++-
 5 files changed, 84 insertions(+), 6 deletions(-)

diff --git a/flecs.c b/flecs.c
index 47e22d445c..cbcd3b37da 100644
--- a/flecs.c
+++ b/flecs.c
@@ -42075,8 +42075,12 @@ void flecs_json_serialize_query_plan(
 
     bool prev_color = ecs_log_enable_colors(true);
     char *plan = ecs_query_plan(q);
-    flecs_json_string_escape(buf, plan);
-    ecs_os_free(plan);
+    if (plan) {
+        flecs_json_string_escape(buf, plan);
+        ecs_os_free(plan);
+    } else {
+        flecs_json_null(buf);
+    }
     ecs_log_enable_colors(prev_color);
 }
 
diff --git a/src/addons/json/serialize_iter.c b/src/addons/json/serialize_iter.c
index 5dd6aef690..4ed2a68912 100644
--- a/src/addons/json/serialize_iter.c
+++ b/src/addons/json/serialize_iter.c
@@ -130,8 +130,12 @@ void flecs_json_serialize_query_plan(
 
     bool prev_color = ecs_log_enable_colors(true);
     char *plan = ecs_query_plan(q);
-    flecs_json_string_escape(buf, plan);
-    ecs_os_free(plan);
+    if (plan) {
+        flecs_json_string_escape(buf, plan);
+        ecs_os_free(plan);
+    } else {
+        flecs_json_null(buf);
+    }
     ecs_log_enable_colors(prev_color);
 }
 
diff --git a/test/meta/project.json b/test/meta/project.json
index 34931964ed..653936f06d 100644
--- a/test/meta/project.json
+++ b/test/meta/project.json
@@ -889,7 +889,9 @@
                 "anonymous_component",
                 "anonymous_tag_recycled",
                 "anonymous_pair_recycled",
-                "anonymous_component_recycled"
+                "anonymous_component_recycled",
+                "serialize_plan_trivial_query",
+                "serialize_plan_nontrivial_query"
             ]
         }, {
             "id": "MetaUtils",
diff --git a/test/meta/src/SerializeQueryInfoToJson.c b/test/meta/src/SerializeQueryInfoToJson.c
index bf4f029995..17bfc13242 100644
--- a/test/meta/src/SerializeQueryInfoToJson.c
+++ b/test/meta/src/SerializeQueryInfoToJson.c
@@ -691,3 +691,61 @@ void SerializeQueryInfoToJson_anonymous_component_recycled(void) {
 
     ecs_fini(world);
 }
+
+void SerializeQueryInfoToJson_serialize_plan_trivial_query(void) {
+    ecs_world_t *world = ecs_init();
+
+    ECS_COMPONENT(world, Position);
+
+    ecs_query_t *q = ecs_query(world, {
+        .terms = {{ ecs_id(Position) }}
+    });
+
+    test_assert(q != NULL);
+
+    ecs_iter_t it = ecs_query_iter(world, q);
+    ecs_iter_to_json_desc_t desc = {
+        .serialize_query_plan = true,
+        .query = q
+    };
+
+    char *json = ecs_iter_to_json(&it, &desc);
+    char *expect = flecs_asprintf("{\"query_plan\":null, \"results\":[]}");
+    test_json(json, expect);
+    ecs_os_free(json);
+    ecs_os_free(expect);
+
+    ecs_query_fini(q);
+
+    ecs_fini(world);
+}
+
+void SerializeQueryInfoToJson_serialize_plan_nontrivial_query(void) {
+    ecs_world_t *world = ecs_init();
+
+    ECS_COMPONENT(world, Position);
+
+    ecs_add_pair(world, ecs_id(Position), EcsOnInstantiate, EcsInherit);
+
+    ecs_query_t *q = ecs_query(world, {
+        .terms = {{ ecs_id(Position) }}
+    });
+
+    test_assert(q != NULL);
+
+    ecs_iter_t it = ecs_query_iter(world, q);
+    ecs_iter_to_json_desc_t desc = {
+        .serialize_query_plan = true,
+        .query = q
+    };
+
+    char *json = ecs_iter_to_json(&it, &desc);
+    char *expect = flecs_asprintf("{\"query_plan\":\"[[0;49m 0. [[[0;37m-1[[0;49m, [[0;32m 1[[0;49m]  setids      \\n[[0;49m 1. [[[0;37m 0[[0;49m, [[0;32m 2[[0;49m]  selfupid    [[0;32m$[[0;49m[[[0;32mthis[[0;49m]           ([[0;34mPosition[[0;49m)\\n[[0;49m 2. [[[0;37m 1[[0;49m, [[0;32m 3[[0;49m]  yield       \\n\", \"results\":[]}");
+    test_json(json, expect);
+    ecs_os_free(json);
+    ecs_os_free(expect);
+
+    ecs_query_fini(q);
+
+    ecs_fini(world);
+}
diff --git a/test/meta/src/main.c b/test/meta/src/main.c
index eed675cb4d..e84906fcee 100644
--- a/test/meta/src/main.c
+++ b/test/meta/src/main.c
@@ -853,6 +853,8 @@ void SerializeQueryInfoToJson_anonymous_component(void);
 void SerializeQueryInfoToJson_anonymous_tag_recycled(void);
 void SerializeQueryInfoToJson_anonymous_pair_recycled(void);
 void SerializeQueryInfoToJson_anonymous_component_recycled(void);
+void SerializeQueryInfoToJson_serialize_plan_trivial_query(void);
+void SerializeQueryInfoToJson_serialize_plan_nontrivial_query(void);
 
 // Testsuite 'MetaUtils'
 void MetaUtils_struct_w_2_i32(void);
@@ -4235,6 +4237,14 @@ bake_test_case SerializeQueryInfoToJson_testcases[] = {
     {
         "anonymous_component_recycled",
         SerializeQueryInfoToJson_anonymous_component_recycled
+    },
+    {
+        "serialize_plan_trivial_query",
+        SerializeQueryInfoToJson_serialize_plan_trivial_query
+    },
+    {
+        "serialize_plan_nontrivial_query",
+        SerializeQueryInfoToJson_serialize_plan_nontrivial_query
     }
 };
 
@@ -4681,7 +4691,7 @@ static bake_test_suite suites[] = {
         "SerializeQueryInfoToJson",
         NULL,
         NULL,
-        25,
+        27,
         SerializeQueryInfoToJson_testcases
     },
     {