MDEV-11461 JSON_TYPE does not recognize integer/double types.

        Integer/Double recognition added.

include/json_lib.h

@@ -172,6 +172,14 @@ enum json_value_types
 };
 
 
+enum json_num_flags
+{
+  JSON_NUM_NEG=1,        /* Number is negative. */
+  JSON_NUM_FRAC_PART=2,  /* The fractional part is not empty. */
+  JSON_NUM_EXP=4,        /* The number has the 'e' part. */
+};
+
+
 typedef struct st_json_engine_t
 {
   json_string_t s;  /* String to parse. */
@@ -185,6 +193,9 @@ typedef struct st_json_engine_t
   enum json_value_types value_type; /* type of the value.*/
   const uchar *value;      /* Points to the value. */
   const uchar *value_begin;/* Points to where the value starts in the JSON. */
+  uint num_flags;  /* the details of the JSON_VALUE_NUMBER, is it negative,
+                      or if it has the fractional part.
+                      See the enum json_num_flags. */
 
   /*
     In most cases the 'value' and 'value_begin' are equal.

mysql-test/r/func_json.result

@@ -215,7 +215,10 @@ json_type("true")
 BOOLEAN
 select json_type('123');
 json_type('123')
-NUMBER
+INTEGER
+select json_type('123.12');
+json_type('123.12')
+DOUBLE
 select json_keys('{"a":{"c":1, "d":2}, "b":2}');
 json_keys('{"a":{"c":1, "d":2}, "b":2}')
 ["a", "b"]

mysql-test/t/func_json.test

@@ -93,6 +93,7 @@ select json_type('{"k1":123, "k2":345}');
 select json_type('[123, "k2", 345]');
 select json_type("true");
 select json_type('123');
+select json_type('123.12');
 
 select json_keys('{"a":{"c":1, "d":2}, "b":2}');
 select json_keys('{"a":{"c":1, "d":2}, "b":2}', "$.a");

sql/item_jsonfunc.cc

@@ -1310,7 +1310,7 @@ String *Item_func_json_type::val_str(String *str)
     type= "STRING";
     break;
   case JSON_VALUE_NUMBER:
-    type= "NUMBER";
+    type= (je.num_flags & JSON_NUM_FRAC_PART) ?  "DOUBLE" : "INTEGER";
     break;
   case JSON_VALUE_TRUE:
   case JSON_VALUE_FALSE:

strings/json_lib.c

@@ -477,13 +477,29 @@ static int json_num_states[NS_NUM_STATES][N_NUM_CLASSES]=
 };
 
 
+static uint json_num_state_flags[NS_NUM_STATES]=
+{
+/*OK*/   0,
+/*GO*/   0,
+/*GO1*/  JSON_NUM_NEG,
+/*ZERO*/ 0,
+/*ZE1*/  0,
+/*INT*/  0,
+/*FRAC*/ JSON_NUM_FRAC_PART,
+/*EX*/   JSON_NUM_EXP,
+/*EX1*/  0,
+};
+
+
 static int skip_num_constant(json_engine_t *j)
 {
   int state= json_num_states[NS_GO][json_num_chr_map[j->s.c_next]];
   int c_len;
 
+  j->num_flags= 0;
   for (;;)
   {
+    j->num_flags|= json_num_state_flags[state];
     if ((c_len= json_next_char(&j->s)) > 0)
     {
       if ((state= json_num_states[state][json_num_chr_map[j->s.c_next]]) > 0)