An after-fix for MDEV-12849 Out-of-range errors when casting hex-hybrid to SIGNED and UNSIGNED

1. Adding the forgotten "SET sql_mode=STRICT_ALL_TABLES" into the test.
2. STRICT_ALL_TABLES revealed that CAST(0xFFFFFFFF AS SIGNED),
   e.g. with a hex number with 8 hex digits, did not work well.
   Fixing Item_func_unsigned::create_tmp_field() and
   Item_func_unsigned::create_field_for_create_select() to handle
   this corner case.

1 files changed, 8 insertions, 0 deletions

diff --git a/sql/item_func.h b/sql/item_func.h
index c644c1abf1b..baa80ede03f 100644
--- a/sql/item_func.h
+++ b/sql/item_func.h
@@ -834,6 +834,14 @@ public:
     unsigned_flag= 0;
   }
   const char *func_name() const { return "cast_as_signed"; }
+  Field *create_tmp_field(bool group, TABLE *table)
+  {
+    return Item::create_tmp_field(false, table,
+                                  MY_INT32_NUM_DECIMAL_DIGITS - 2 +
+                                  unsigned_flag);
+  }
+  Field *create_field_for_create_select(TABLE *table)
+  { return Item_func_signed::create_tmp_field(false, table); }
   longlong val_int()
   {
     longlong value= args[0]->val_int_signed_typecast();