MDEV-11453 JSON_CONTAINS returns incorrect values.

        The weird logic of json_contains was implemented.

6 files changed, 237 insertions, 92 deletions

diff --git a/include/json_lib.h b/include/json_lib.h
index b2ea39cd728..abef3e60db6 100644
--- a/include/json_lib.h
+++ b/include/json_lib.h
@@ -311,6 +311,7 @@ int json_skip_level(json_engine_t *j);
 */
 #define json_value_scalar(je)  ((je)->value_type > JSON_VALUE_ARRAY)
 
+
 /*
   Look for the JSON PATH in the json string.
   Function can be called several times with same JSON/PATH to
diff --git a/mysql-test/r/func_json.result b/mysql-test/r/func_json.result
index bae7da495b0..c972057e37c 100644
--- a/mysql-test/r/func_json.result
+++ b/mysql-test/r/func_json.result
@@ -90,6 +90,57 @@ json_contains('"youth"', '"you"')
 0
 select json_contains('[1]', '[1]', '$', '$[0]');
 ERROR 42000: Incorrect parameter count in the call to native function 'json_contains'
+select json_contains('', '', '$');
+json_contains('', '', '$')
+0
+select json_contains('null', 'null', '$');
+json_contains('null', 'null', '$')
+1
+select json_contains('"10"', '"10"', '$');
+json_contains('"10"', '"10"', '$')
+1
+select json_contains('"10"', '10', '$');
+json_contains('"10"', '10', '$')
+0
+select json_contains('10.1', '10', '$');
+json_contains('10.1', '10', '$')
+0
+select json_contains('10.0', '10', '$');
+json_contains('10.0', '10', '$')
+1
+select json_contains('[1]', '1');
+json_contains('[1]', '1')
+1
+select json_contains('[2, 1]', '1');
+json_contains('[2, 1]', '1')
+1
+select json_contains('[2, [2, 3], 1]', '1');
+json_contains('[2, [2, 3], 1]', '1')
+1
+select json_contains('[4, [2, 3], 1]', '2');
+json_contains('[4, [2, 3], 1]', '2')
+1
+select json_contains('[2, 1]', '[1, 2]');
+json_contains('[2, 1]', '[1, 2]')
+1
+select json_contains('[2, 1]', '[1, 0, 2]');
+json_contains('[2, 1]', '[1, 0, 2]')
+0
+select json_contains('[2, 0, 3, 1]', '[1, 2]');
+json_contains('[2, 0, 3, 1]', '[1, 2]')
+1
+select json_contains('{"b":[1,2], "a":1}', '{"a":1, "b":2}');
+json_contains('{"b":[1,2], "a":1}', '{"a":1, "b":2}')
+1
+select json_contains('{"a":1}', '{}');
+json_contains('{"a":1}', '{}')
+1
+select json_contains('[1, {"a":1}]', '{}');
+json_contains('[1, {"a":1}]', '{}')
+1
+select json_contains('[1, {"a":1}]', '{"a":1}');
+json_contains('[1, {"a":1}]', '{"a":1}')
+1
 select json_contains_path('{"key1":1, "key2":[2,3]}', "oNE", "$.key2[1]");
 json_contains_path('{"key1":1, "key2":[2,3]}', "oNE", "$.key2[1]")
 1
diff --git a/mysql-test/t/func_json.test b/mysql-test/t/func_json.test
index 12e1c742a26..d3d75fa3913 100644
--- a/mysql-test/t/func_json.test
+++ b/mysql-test/t/func_json.test
@@ -36,6 +36,23 @@ select json_contains('"you"', '"you"');
 select json_contains('"youth"', '"you"');
 --error ER_WRONG_PARAMCOUNT_TO_NATIVE_FCT
 select json_contains('[1]', '[1]', '$', '$[0]');
+select json_contains('', '', '$');
+select json_contains('null', 'null', '$');
+select json_contains('"10"', '"10"', '$');
+select json_contains('"10"', '10', '$');
+select json_contains('10.1', '10', '$');
+select json_contains('10.0', '10', '$');
+select json_contains('[1]', '1');
+select json_contains('[2, 1]', '1');
+select json_contains('[2, [2, 3], 1]', '1');
+select json_contains('[4, [2, 3], 1]', '2');
+select json_contains('[2, 1]', '[1, 2]');
+select json_contains('[2, 1]', '[1, 0, 2]');
+select json_contains('[2, 0, 3, 1]', '[1, 2]');
+select json_contains('{"b":[1,2], "a":1}', '{"a":1, "b":2}');
+select json_contains('{"a":1}', '{}');
+select json_contains('[1, {"a":1}]', '{}');
+select json_contains('[1, {"a":1}]', '{"a":1}');
 
 select json_contains_path('{"key1":1, "key2":[2,3]}', "oNE", "$.key2[1]");
 select json_contains_path('{"key1":1, "key2":[2,3]}', "oNE", "$.key2[10]");
diff --git a/sql/item_jsonfunc.cc b/sql/item_jsonfunc.cc
index adb0912f1fc..e3fa34cd72c 100644
--- a/sql/item_jsonfunc.cc
+++ b/sql/item_jsonfunc.cc
@@ -596,39 +596,162 @@ error:
 }
 
 
-bool Item_func_json_contains::fix_fields(THD *thd, Item **ref)
-{
-  return alloc_tmp_paths(thd, arg_count-2, &paths, &tmp_paths) ||
-         Item_int_func::fix_fields(thd, ref);
-}
-
-
 void Item_func_json_contains::fix_length_and_dec()
 {
   a2_constant= args[1]->const_item();
   a2_parsed= FALSE;
-  mark_constant_paths(paths, args+2, arg_count-2);
+  if (arg_count > 2)
+    path.set_constant_flag(args[2]->const_item());
   Item_int_func::fix_length_and_dec();
 }
 
 
-void Item_func_json_contains::cleanup()
+static int find_key_in_object(json_engine_t *j, json_string_t *key)
 {
-  if (tmp_paths)
+  const uchar *c_str= key->c_str;
+
+  while (json_scan_next(j) == 0 && j->state != JST_OBJ_END)
   {
-    for (uint i= arg_count-2; i>0; i--)
-      tmp_paths[i-1].free();
-    tmp_paths= 0;
+    DBUG_ASSERT(j->state == JST_KEY);
+    if (json_key_matches(j, key))
+      return TRUE;
+    if (json_skip_key(j))
+      return FALSE;
+    key->c_str= c_str;
   }
-  Item_int_func::cleanup();
+
+  return FALSE;
+}
+
+
+static int check_contains(json_engine_t *js, json_engine_t *value)
+{
+  json_engine_t loc_js;
+  bool set_js;
+
+  switch (js->value_type)
+  {
+  case JSON_VALUE_OBJECT:
+  {
+    json_string_t key_name;
+
+    if (value->value_type != JSON_VALUE_OBJECT)
+      return FALSE;
+
+    loc_js= *js;
+    set_js= FALSE;
+    json_string_set_cs(&key_name, value->s.cs);
+    while (json_scan_next(value) == 0 && value->state != JST_OBJ_END)
+    {
+      const uchar *k_start, *k_end;
+
+      DBUG_ASSERT(value->state == JST_KEY);
+      k_start= value->s.c_str;
+      while (json_read_keyname_chr(value) == 0)
+        k_end= value->s.c_str;
+
+      if (value->s.error || json_read_value(value))
+        return FALSE;
+
+      if (set_js)
+        *js= loc_js;
+      else
+        set_js= TRUE;
+
+      json_string_set_str(&key_name, k_start, k_end);
+      if (!find_key_in_object(js, &key_name) ||
+          json_read_value(js) ||
+          !check_contains(js, value))
+        return FALSE;
+    }
+
+    return value->state == JST_OBJ_END && !json_skip_level(js);
+  }
+  case JSON_VALUE_ARRAY:
+    if (value->value_type != JSON_VALUE_ARRAY)
+    {
+      while (json_scan_next(js) == 0 && js->state != JST_ARRAY_END)
+      {
+        DBUG_ASSERT(js->state == JST_VALUE);
+        if (json_read_value(js))
+          return FALSE;
+
+        if (check_contains(js, value))
+        {
+          if (json_skip_level(js))
+            return FALSE;
+          return TRUE;
+        }
+        if (value->s.error || js->s.error)
+          return FALSE;
+      }
+      return FALSE;
+    }
+    /* else */
+    loc_js= *js;
+    set_js= FALSE;
+    while (json_scan_next(value) == 0 && value->state != JST_ARRAY_END)
+    {
+      DBUG_ASSERT(value->state == JST_VALUE);
+      if (json_read_value(value))
+        return FALSE;
+
+      if (set_js)
+        *js= loc_js;
+      else
+        set_js= TRUE;
+      if (!check_contains(js, value))
+        return FALSE;
+    }
+
+    return value->state == JST_ARRAY_END;
+
+  case JSON_VALUE_STRING:
+    if (value->value_type != JSON_VALUE_STRING)
+      return FALSE;
+    /*
+       TODO: make proper json-json comparison here that takes excapint
+             into account.
+     */
+    return value->value_len == js->value_len &&
+           memcmp(value->value, js->value, value->value_len) == 0;
+  case JSON_VALUE_NUMBER:
+    if (value->value_type == JSON_VALUE_NUMBER)
+    {
+      double d_j, d_v;
+      char *end;
+      int err;
+
+      d_j= my_strntod(js->s.cs, (char *) js->value, js->value_len,
+                      &end, &err);;
+      d_v= my_strntod(value->s.cs, (char *) value->value, value->value_len,
+                      &end, &err);;
+
+      return (fabs(d_j - d_v) < 1e-12);
+    }
+    else
+      return FALSE;
+
+  default:
+    break;
+  }
+
+  /*
+    We have these not mentioned in the 'switch' above:
+
+    case JSON_VALUE_TRUE:
+    case JSON_VALUE_FALSE:
+    case JSON_VALUE_NULL:
+  */
+  return value->value_type == js->value_type;
 }
 
 
 longlong Item_func_json_contains::val_int()
 {
   String *js= args[0]->val_str(&tmp_js);
-  json_engine_t je;
-  uint n_arg;
+  json_engine_t je, ve;
+  int result;
 
   if ((null_value= args[0]->null_value))
     return 0;
@@ -648,54 +771,37 @@ longlong Item_func_json_contains::val_int()
   json_scan_start(&je, js->charset(),(const uchar *) js->ptr(),
                   (const uchar *) js->ptr() + js->length());
 
-  if (arg_count<3) /* No path specified. */
-  {
-    if (json_read_value(&je))
-      goto error;
-    String jv_str((const char *)je.value_begin,
-                  je.value_end - je.value_begin, js->charset());
-    return val->eq(&jv_str, js->charset());
-  }
-
-  for (n_arg=2; n_arg < arg_count; n_arg++)
+  if (arg_count>2) /* Path specified. */
   {
     uint array_counters[JSON_DEPTH_LIMIT];
-    json_path_with_flags *c_path= paths + n_arg - 2;
-    if (!c_path->parsed)
+    if (!path.parsed)
     {
-      String *s_p= args[n_arg]->val_str(tmp_paths+(n_arg-2));
+      String *s_p= args[2]->val_str(&tmp_path);
       if (s_p &&
-          json_path_setup(&c_path->p,s_p->charset(),(const uchar *) s_p->ptr(),
-                          (const uchar *) s_p->ptr() + s_p->length()))
+          json_path_setup(&path.p,s_p->charset(),(const uchar *) s_p->ptr(),
+                          (const uchar *) s_p->end()))
         goto error;
-      c_path->parsed= c_path->constant;
+      path.parsed= path.constant;
     }
-
-    if (args[n_arg]->null_value)
+    if (args[2]->null_value)
       goto error;
 
-    json_scan_start(&je, js->charset(),(const uchar *) js->ptr(),
-                    (const uchar *) js->ptr() + js->length());
-
-    c_path->cur_step= c_path->p.steps;
-    if (json_find_path(&je, &c_path->p, &c_path->cur_step, array_counters))
-    {
-      /* Path wasn't found. */
-      if (je.s.error)
-        goto error;
-      continue;
-    }
-
-    if (json_read_value(&je))
+    path.cur_step= path.p.steps;
+    if (json_find_path(&je, &path.p, &path.cur_step, array_counters))
       goto error;
-    String jv_str((const char *)je.value_begin,
-                  je.value_end - je.value_begin, js->charset());
-    if (val->eq(&jv_str, js->charset()))
-      return 1;
   }
 
+  json_scan_start(&ve, val->charset(),(const uchar *) val->ptr(),
+                  (const uchar *) val->end());
 
-  return 0;
+  if (json_read_value(&je) || json_read_value(&ve))
+    return FALSE;
+
+  result= check_contains(&je, &ve);
+  if (je.s.error || ve.s.error)
+    goto error;
+
+  return result;
 
 error:
   null_value= 1;
@@ -2002,41 +2108,6 @@ static int append_json_path(String *str, const json_path_t *p)
 }
 
 
-#ifdef DUMMY
-static int json_path_compare(const json_path_t *a, const json_path_t *b)
-{
-  uint i, a_len= a->last_step - a->steps, b_len= b->last_step - b->steps;
-
-  if (a_len > b_len)
-    return -2;
-
-  for (i=0; i <= a_len; i++)
-  {
-    const json_path_step_t *sa= a->steps + i;
-    const json_path_step_t *sb= b->steps + i;
-
-    if (!((sa->type & sb->type) & JSON_PATH_KEY_OR_ARRAY))
-      return -1;
-    
-    if (sa->type & JSON_PATH_ARRAY)
-    {
-      if (!(sa->type & JSON_PATH_WILD) && sa->n_item != sb->n_item)
-        return -1;
-    }
-    else /* JSON_PATH_KEY */
-    {
-      if (!(sa->type & JSON_PATH_WILD) &&
-          (sa->key_end - sa->key != sb->key_end - sb->key ||
-           memcmp(sa->key, sb->key, sa->key_end - sa->key) != 0))
-        return -1;
-    }
-  }
-
-  return b_len > a_len;
-}
-#endif /*DUMMY*/
-
-
 static int json_path_compare(const json_path_t *a, const json_path_t *b)
 {
   const json_path_step_t *sa= a->steps + 1;
diff --git a/sql/item_jsonfunc.h b/sql/item_jsonfunc.h
index da9baf47648..e6f26d95b13 100644
--- a/sql/item_jsonfunc.h
+++ b/sql/item_jsonfunc.h
@@ -174,17 +174,15 @@ class Item_func_json_contains: public Item_int_func
 {
 protected:
   String tmp_js;
-  json_path_with_flags *paths;
-  String *tmp_paths;
+  json_path_with_flags path;
+  String tmp_path;
   bool a2_constant, a2_parsed;
   String tmp_val, *val;
 public:
   Item_func_json_contains(THD *thd, List<Item> &list):
-    Item_int_func(thd, list), tmp_paths(0) {}
+    Item_int_func(thd, list) {}
   const char *func_name() const { return "json_contains"; }
-  bool fix_fields(THD *thd, Item **ref);
   void fix_length_and_dec();
-  void cleanup();
   longlong val_int();
   Item *get_copy(THD *thd, MEM_ROOT *mem_root)
   { return get_item_copy<Item_func_json_contains>(thd, mem_root, this); }
diff --git a/strings/json_lib.c b/strings/json_lib.c
index a9498070195..015ce1f39f8 100644
--- a/strings/json_lib.c
+++ b/strings/json_lib.c
@@ -1182,6 +1182,13 @@ int json_skip_level(json_engine_t *j)
 
 int json_skip_key(json_engine_t *j)
 {
+  if (j->state == JST_KEY)
+  {
+    while (json_read_keyname_chr(j) == 0);
+    if (j->s.error)
+      return 1;
+  }
+
   if (json_read_value(j))
     return 1;