Bug #31253: crash comparing datetime to double

convert(<invalid time>, datetime) in WHERE caused crash as function
returned (void*)NULL, but did not flag SQL NULL. It does now.


mysql-test/r/type_datetime.result:
  show that convert() to datetime in a WHERE-clause will no longer crash
  the server on invalid input.
mysql-test/t/type_datetime.test:
  show that convert() to datetime in a WHERE-clause will no longer crash
  the server on invalid input.
sql/item.cc:
  When failing to process time values, do not just return (void*)NULL,
  but flag SQL NULL as well so no caller will try to process the 0x0L.
  This makes behaviour for Item::Item::val_decimal_from_date() and
  Item::Item::val_decimal_from_time() identical.

1 files changed, 1 insertions, 0 deletions

diff --git a/sql/item.cc b/sql/item.cc
index e9b2904e3da..5f73b016e50 100644
--- a/sql/item.cc
+++ b/sql/item.cc
@@ -274,6 +274,7 @@ my_decimal *Item::val_decimal_from_date(my_decimal *decimal_value)
   if (get_date(&ltime, TIME_FUZZY_DATE))
   {
     my_decimal_set_zero(decimal_value);
+    null_value= 1;                               // set NULL, stop processing
     return 0;
   }
   return date2my_decimal(&ltime, decimal_value);