Bug#27452082 ASSERTION FAILED: !TABLE->IN_USE->IS_ERROR() IN UPDATE_GENERATED_READ_FIELDS

It's a SELECT with WHERE "(-1) minus 0x4d".
this operation has a result type of "unsigned" (because 0x4d is unsigned
integer) and the result (-78) doesn't fit int an unsigned type.
This WHERE is evaluated by InnoDB in index condition pushdown:
#0 my_error
#1 Item_func::raise_numeric_overflow
...
#7 Item_cond_and::val_int
#8 innobase_index_cond
...
#12 handler::index_read_map
...
#15 handler::multi_range_read_next
...
#20 rr_quick
#21 join_init_read_record
As val_int() has no "error" return code, the execution continues until
frame #12; there we call update_generated_read_fields(), which has
an assertion about thd->is_error() which fails.

Fix: it would be nice to detect error as soon as it happens, i.e. in innodb
code right after it calls val_bool(). But innodb's index condition
pushdown functions only have found / not found return codes so they cannot
signal "error" to the upper layers. Same is true for MyISAM. Moreover,
"thd" isn't easily accessible there.
Adding a detection a bit above in the stack (handler::* functions which
do index reads) is also possible but would require fixing ~20
functions.
The chosen fix here is to change update_generated_*_fields()
to return error if thd->is_error() is true.
Note that the removed assertion was already one cause of
bug 27041382.

Author: Guilhem Bichot

mysql-test/suite/gcol/r/gcol_bugfixes.result

@@ -868,3 +868,15 @@ LOAD DATA INFILE '../../std_data/loaddata5.dat'
  INTO TABLE t1 FIELDS TERMINATED BY '' ENCLOSED BY '' (c1) ;
 ERROR 42000: Trigger 'trg1' has an error in its body: 'You have an error in your SQL syntax; check the manual that corresponds to your MySQL server version for the right syntax to use near 't1 VALUES (1)' at line 1'
 DROP TABLE t1;
+#
+# Bug#27452082 ASSERTION FAILED: !TABLE->IN_USE->IS_ERROR() IN UPDATE_GENERATED_READ_FIELDS
+#
+CREATE TABLE t (
+a INT,
+b INT GENERATED ALWAYS AS (MAKETIME(1,1,1)) STORED,
+KEY (a)
+);
+INSERT INTO t (a) VALUES (32767),(-1);
+SELECT * FROM t WHERE a>-19106 AND a-0x4d;
+ERROR 22003: BIGINT UNSIGNED value is out of range in '(`test`.`t`.`a` - 0x4d)'
+DROP TABLE t;

mysql-test/suite/gcol/t/gcol_bugfixes.test

@@ -848,3 +848,17 @@ LOAD DATA INFILE '../../std_data/loaddata5.dat'
  INTO TABLE t1 FIELDS TERMINATED BY '' ENCLOSED BY '' (c1) ;
 
 DROP TABLE t1;
+
+--echo #
+--echo # Bug#27452082 ASSERTION FAILED: !TABLE->IN_USE->IS_ERROR() IN UPDATE_GENERATED_READ_FIELDS
+--echo #
+
+CREATE TABLE t (
+  a INT,
+  b INT GENERATED ALWAYS AS (MAKETIME(1,1,1)) STORED,
+  KEY (a)
+);
+INSERT INTO t (a) VALUES (32767),(-1);
+--error ER_DATA_OUT_OF_RANGE
+SELECT * FROM t WHERE a>-19106 AND a-0x4d;
+DROP TABLE t;

sql/table.cc

@@ -6738,7 +6738,7 @@ void repoint_field_to_record(TABLE *table, uchar *old_rec, uchar *new_rec) {
 bool update_generated_read_fields(uchar *buf, TABLE *table, uint active_index) {
   DBUG_ENTER("update_generated_read_fields");
   DBUG_ASSERT(table && table->vfield);
-  DBUG_ASSERT(!table->in_use->is_error());
+  if (table->in_use->is_error()) DBUG_RETURN(true);
   if (active_index != MAX_KEY && table->key_read) {
     /*
       The covering index is providing all necessary columns, including
@@ -6833,7 +6833,8 @@ bool update_generated_write_fields(const MY_BITMAP *bitmap, TABLE *table) {
   int error = 0;
 
   DBUG_ASSERT(table->vfield);
-  DBUG_ASSERT(!table->in_use->is_error());
+  if (table->in_use->is_error()) DBUG_RETURN(true);
+
   /* Iterate over generated fields in the table */
   for (vfield_ptr = table->vfield; *vfield_ptr; vfield_ptr++) {
     Field *vfield;