BUG#11927: Warnings shown for CAST( chr as signed) but not (chr + 0)

 When implicitly converting string fields to numbers the 
 string-to-number conversion error was not sent to the client.
 Added code to send the conversion error as warning.
 
 We also need to prevent generation of warnings from the places
 where val_xxx() methods are called for the sole purpose of updating
 the Item::null_value flag.
 To achieve that a special function is added (and called) : 
 update_null_value(). This function will set the no_errors flag and
 will call val_xxx(). The warning generation in Field_string::val_xxx()
 will use the flag when generating the conversion warnings. 

mysql-test/r/compare.result

@@ -46,6 +46,10 @@ create table t1 (a tinyint(1),b binary(1));
 insert into t1 values (0x01,0x01);
 select * from t1 where a=b;
 a	b
+Warnings:
+Warning	1292	Truncated incorrect DOUBLE value: '
'
 select * from t1 where a=b and b=0x01;
 a	b
+Warnings:
+Warning	1292	Truncated incorrect DOUBLE value: '
'
 drop table if exists t1;

mysql-test/r/func_gconcat.result

@@ -64,11 +64,49 @@ grp	group_concat(a order by a,d+c-ascii(c)-a)
 1	1
 2	2,3
 3	4,5,6,7,8,9
+Warnings:
+Warning	1292	Truncated incorrect DOUBLE value: 'a         '
+Warning	1292	Truncated incorrect DOUBLE value: 'a         '
+Warning	1292	Truncated incorrect DOUBLE value: 'a         '
+Warning	1292	Truncated incorrect DOUBLE value: 'b         '
+Warning	1292	Truncated incorrect DOUBLE value: 'b         '
+Warning	1292	Truncated incorrect DOUBLE value: 'c         '
+Warning	1292	Truncated incorrect DOUBLE value: 'a         '
+Warning	1292	Truncated incorrect DOUBLE value: 'E         '
+Warning	1292	Truncated incorrect DOUBLE value: 'b         '
+Warning	1292	Truncated incorrect DOUBLE value: 'C         '
+Warning	1292	Truncated incorrect DOUBLE value: 'b         '
+Warning	1292	Truncated incorrect DOUBLE value: 'D         '
+Warning	1292	Truncated incorrect DOUBLE value: 'd         '
+Warning	1292	Truncated incorrect DOUBLE value: 'd         '
+Warning	1292	Truncated incorrect DOUBLE value: 'd         '
+Warning	1292	Truncated incorrect DOUBLE value: 'd         '
+Warning	1292	Truncated incorrect DOUBLE value: 'c         '
+Warning	1292	Truncated incorrect DOUBLE value: 'D         '
 select grp,group_concat(a order by d+c-ascii(c),a) from t1 group by grp;
 grp	group_concat(a order by d+c-ascii(c),a)
 1	1
 2	3,2
 3	7,8,4,6,9,5
+Warnings:
+Warning	1292	Truncated incorrect DOUBLE value: 'a         '
+Warning	1292	Truncated incorrect DOUBLE value: 'a         '
+Warning	1292	Truncated incorrect DOUBLE value: 'a         '
+Warning	1292	Truncated incorrect DOUBLE value: 'b         '
+Warning	1292	Truncated incorrect DOUBLE value: 'b         '
+Warning	1292	Truncated incorrect DOUBLE value: 'c         '
+Warning	1292	Truncated incorrect DOUBLE value: 'a         '
+Warning	1292	Truncated incorrect DOUBLE value: 'E         '
+Warning	1292	Truncated incorrect DOUBLE value: 'b         '
+Warning	1292	Truncated incorrect DOUBLE value: 'C         '
+Warning	1292	Truncated incorrect DOUBLE value: 'b         '
+Warning	1292	Truncated incorrect DOUBLE value: 'D         '
+Warning	1292	Truncated incorrect DOUBLE value: 'd         '
+Warning	1292	Truncated incorrect DOUBLE value: 'd         '
+Warning	1292	Truncated incorrect DOUBLE value: 'd         '
+Warning	1292	Truncated incorrect DOUBLE value: 'd         '
+Warning	1292	Truncated incorrect DOUBLE value: 'c         '
+Warning	1292	Truncated incorrect DOUBLE value: 'D         '
 select grp,group_concat(c order by 1) from t1 group by grp;
 grp	group_concat(c order by 1)
 1	a

mysql-test/r/func_group.result

@@ -62,6 +62,13 @@ NULL	NULL
 1	7
 2	20.25
 3	45.483163247594
+Warnings:
+Warning	1292	Truncated incorrect DOUBLE value: 'a         '
+Warning	1292	Truncated incorrect DOUBLE value: 'a         '
+Warning	1292	Truncated incorrect DOUBLE value: 'b         '
+Warning	1292	Truncated incorrect DOUBLE value: 'c         '
+Warning	1292	Truncated incorrect DOUBLE value: 'C         '
+Warning	1292	Truncated incorrect DOUBLE value: 'E         '
 create table t2 (grp int, a bigint unsigned, c char(10));
 insert into t2 select grp,max(a)+max(grp),max(c) from t1 group by grp;
 replace into t2 select grp, a, c from t1 limit 2,1;

mysql-test/r/type_varchar.result

@@ -453,3 +453,38 @@ id	name_id	id	en	cz
 2	3	2	en string 2	cz string 2
 3	3	3	en string 3	cz string 3
 drop table t1, t2, t3;
+CREATE TABLE t1 (a CHAR(2));
+INSERT INTO t1 VALUES (10), (50), (30), ('1a'), (60), ('t');
+SELECT a,(a + 0) FROM t1 ORDER BY a;
+a	(a + 0)
+10	10
+1a	1
+30	30
+50	50
+60	60
+t	0
+Warnings:
+Warning	1292	Truncated incorrect DOUBLE value: '1a'
+Warning	1292	Truncated incorrect DOUBLE value: 't '
+SELECT a,(a DIV 2) FROM t1 ORDER BY a;
+a	(a DIV 2)
+10	5
+1a	0
+30	15
+50	25
+60	30
+t	0
+Warnings:
+Warning	1292	Truncated incorrect INTEGER value: '1a'
+Warning	1292	Truncated incorrect INTEGER value: 't '
+SELECT a,CAST(a AS SIGNED) FROM t1 ORDER BY a;
+a	CAST(a AS SIGNED)
+10	10
+1a	1
+30	30
+50	50
+60	60
+t	0
+Warnings:
+Warning	1292	Truncated incorrect INTEGER value: '1a'
+Warning	1292	Truncated incorrect INTEGER value: 't'

mysql-test/t/type_varchar.test

@@ -187,3 +187,12 @@ left join t3 on t1.id=t3.id order by t3.id;
 --disable_metadata
 --enable_ps_protocol
 drop table t1, t2, t3;
+
+#
+# Bug #11927: Warnings shown for CAST( chr as signed) but not (chr + 0)
+#
+CREATE TABLE t1 (a CHAR(2));
+INSERT INTO t1 VALUES (10), (50), (30), ('1a'), (60), ('t');
+SELECT a,(a + 0) FROM t1 ORDER BY a;
+SELECT a,(a DIV 2) FROM t1 ORDER BY a;
+SELECT a,CAST(a AS SIGNED) FROM t1 ORDER BY a;

sql/field.cc

@@ -47,6 +47,8 @@ uchar Field_null::null[1]={1};
 const char field_separator=',';
 
 #define DOUBLE_TO_STRING_CONVERSION_BUFFER_SIZE 320
+#define LONGLONG_TO_STRING_CONVERSION_BUFFER_SIZE 128
+#define DECIMAL_TO_STRING_CONVERSION_BUFFER_SIZE 128
 #define BLOB_PACK_LENGTH_TO_MAX_LENGH(arg) \
 ((ulong) ((LL(1) << min(arg, 4) * 8) - LL(1)))
 
@@ -5954,19 +5956,49 @@ int Field_longstr::store_decimal(const my_decimal *d)
 
 double Field_string::val_real(void)
 {
-  int not_used;
-  char *end_not_used;
+  int error;
+  char *end;
   CHARSET_INFO *cs= charset();
-  return my_strntod(cs,ptr,field_length,&end_not_used,&not_used);
+  double result;
+  
+  result=  my_strntod(cs,ptr,field_length,&end,&error);
+  if (!table->in_use->no_errors &&
+      (error || (field_length != (uint32)(end - ptr) && 
+                !check_if_only_end_space(cs, end, ptr + field_length))))
+  {
+    char buf[DOUBLE_TO_STRING_CONVERSION_BUFFER_SIZE];
+    String tmp(buf, sizeof(buf), cs);
+    tmp.copy(ptr, field_length, cs);
+    push_warning_printf(current_thd, MYSQL_ERROR::WARN_LEVEL_WARN,
+                        ER_TRUNCATED_WRONG_VALUE, 
+                        ER(ER_TRUNCATED_WRONG_VALUE),
+                        "DOUBLE", tmp.c_ptr());
+  }
+  return result;
 }
 
 
 longlong Field_string::val_int(void)
 {
-  int not_used;
-  char *end_not_used;
-  CHARSET_INFO *cs=charset();
-  return my_strntoll(cs,ptr,field_length,10,&end_not_used,&not_used);
+  int error;
+  char *end;
+  CHARSET_INFO *cs= charset();
+  longlong result;
+
+  result= my_strntoll(cs,ptr,field_length,10,&end,&error);
+  if (!table->in_use->no_errors &&
+      (error || (field_length != (uint32)(end - ptr) && 
+                !check_if_only_end_space(cs, end, ptr + field_length))))
+  {
+    char buf[LONGLONG_TO_STRING_CONVERSION_BUFFER_SIZE];
+    String tmp(buf, sizeof(buf), cs);
+    tmp.copy(ptr, field_length, cs);
+    push_warning_printf(current_thd, MYSQL_ERROR::WARN_LEVEL_WARN,
+                        ER_TRUNCATED_WRONG_VALUE, 
+                        ER(ER_TRUNCATED_WRONG_VALUE),
+                        "INTEGER", tmp.c_ptr());
+  }
+  return result;
 }
 
 
@@ -5983,8 +6015,20 @@ String *Field_string::val_str(String *val_buffer __attribute__((unused)),
 
 my_decimal *Field_string::val_decimal(my_decimal *decimal_value)
 {
-  str2my_decimal(E_DEC_FATAL_ERROR, ptr, field_length, charset(),
+  int err= str2my_decimal(E_DEC_FATAL_ERROR, ptr, field_length, charset(),
                  decimal_value);
+  if (!table->in_use->no_errors && err)
+  {
+    char buf[DECIMAL_TO_STRING_CONVERSION_BUFFER_SIZE];
+    CHARSET_INFO *cs= charset();
+    String tmp(buf, sizeof(buf), cs);
+    tmp.copy(ptr, field_length, cs);
+    push_warning_printf(current_thd, MYSQL_ERROR::WARN_LEVEL_WARN,
+                        ER_TRUNCATED_WRONG_VALUE, 
+                        ER(ER_TRUNCATED_WRONG_VALUE),
+                        "DECIMAL", tmp.c_ptr());
+  }
+
   return decimal_value;
 }
 

sql/item.cc

@@ -2175,12 +2175,6 @@ void Item_string::print(String *str)
 }
 
 
-inline bool check_if_only_end_space(CHARSET_INFO *cs, char *str, char *end)
-{
-  return str+ cs->cset->scan(cs, str, end, MY_SEQ_SPACES) == end;
-}
-
-
 double Item_string::val_real()
 {
   DBUG_ASSERT(fixed == 1);
@@ -4764,6 +4758,22 @@ bool Item_field::send(Protocol *protocol, String *buffer)
 }
 
 
+void Item_field::update_null_value() 
+{ 
+  /* 
+    need to set no_errors to prevent warnings about type conversion 
+    popping up.
+  */
+  THD *thd= field->table->in_use;
+  int no_errors;
+
+  no_errors= thd->no_errors;
+  thd->no_errors= 1;
+  Item::update_null_value();
+  thd->no_errors= no_errors;
+}
+
+
 Item_ref::Item_ref(Name_resolution_context *context_arg,
                    Item **item, const char *table_name_arg,
                    const char *field_name_arg)
@@ -6120,7 +6130,7 @@ bool Item_cache_row::null_inside()
     }
     else
     {
-      values[i]->val_int();
+      values[i]->update_null_value();
       if (values[i]->null_value)
 	return 1;
     }

sql/item.h

@@ -715,6 +715,11 @@ public:
   */
   virtual bool is_null() { return 0; }
 
+  /*
+   Make sure the null_value member has a correct value.
+  */
+  virtual void update_null_value () { (void) val_int(); }
+
   /*
     Inform the item that there will be no distinction between its result
     being FALSE or NULL.
@@ -1282,6 +1287,7 @@ public:
   bool get_date_result(TIME *ltime,uint fuzzydate);
   bool get_time(TIME *ltime);
   bool is_null() { return field->is_null(); }
+  void update_null_value();
   Item *get_tmp_table_item(THD *thd);
   bool collect_item_field_processor(byte * arg);
   bool find_item_in_field_list_processor(byte *arg);

sql/item_func.h

@@ -157,7 +157,7 @@ public:
     return (null_value=args[0]->get_time(ltime));
   }
   bool is_null() { 
-    (void) val_int();  /* Discard result. It sets null_value as side-effect. */ 
+    update_null_value();
     return null_value; 
   }
   void signal_divide_by_null();
@@ -241,7 +241,7 @@ public:
   virtual double real_op()= 0;
   virtual my_decimal *decimal_op(my_decimal *)= 0;
   virtual String *str_op(String *)= 0;
-  bool is_null() { (void) val_real(); return null_value; }
+  bool is_null() { update_null_value(); return null_value; }
 };
 
 /* function where type of result detected by first argument */

sql/item_subselect.h

@@ -91,7 +91,7 @@ public:
   enum Type type() const;
   bool is_null()
   {
-    val_int();
+    update_null_value();
     return null_value;
   }
   bool fix_fields(THD *thd, Item **ref);

sql/item_sum.cc

@@ -1050,7 +1050,7 @@ bool Item_sum_count::add()
     count++;
   else
   {
-    (void) args[0]->val_int();
+    args[0]->update_null_value();
     if (!args[0]->null_value)
       count++;
   }
@@ -1956,7 +1956,7 @@ void Item_sum_count::reset_field()
     nr=1;
   else
   {
-    (void) args[0]->val_int();
+    args[0]->update_null_value();
     if (!args[0]->null_value)
       nr=1;
   }
@@ -2066,7 +2066,7 @@ void Item_sum_count::update_field()
     nr++;
   else
   {
-    (void) args[0]->val_int();
+    args[0]->update_null_value();
     if (!args[0]->null_value)
       nr++;
   }
@@ -2546,7 +2546,7 @@ bool Item_sum_count_distinct::setup(THD *thd)
       return TRUE;                              // End of memory
     if (item->const_item())
     {
-      (void) item->val_int();
+      item->update_null_value();
       if (item->null_value)
 	always_null=1;
     }

sql/item_sum.h

@@ -587,7 +587,7 @@ public:
   double val_real();
   longlong val_int();
   my_decimal *val_decimal(my_decimal *);
-  bool is_null() { (void) val_int(); return null_value; }
+  bool is_null() { update_null_value(); return null_value; }
   String *val_str(String*);
   enum_field_types field_type() const
   {
@@ -649,7 +649,7 @@ public:
   { /* can't be fix_fields()ed */ return (longlong) rint(val_real()); }
   String *val_str(String*);
   my_decimal *val_decimal(my_decimal *);
-  bool is_null() { (void) val_int(); return null_value; }
+  bool is_null() { update_null_value(); return null_value; }
   enum_field_types field_type() const
   {
     return hybrid_type == DECIMAL_RESULT ?

sql/sql_string.h

@@ -355,3 +355,9 @@ public:
     return (s->alloced && Ptr >= s->Ptr && Ptr < s->Ptr + s->str_length);
   }
 };
+
+static inline bool check_if_only_end_space(CHARSET_INFO *cs, char *str, 
+                                           char *end)
+{
+  return str+ cs->cset->scan(cs, str, end, MY_SEQ_SPACES) == end;
+}