MDEV-35288 Assertion `!is_cond()' failed in virtual longlong Item_bool_func::val_int()

Boolean function now uses val_bool to get string result (val_str())

Author: sanja-byelkin

mysql-test/main/bool_innodb.result

@@ -0,0 +1,10 @@
+#
+# MDEV-35288: Assertion `!is_cond()' failed in
+# virtual longlong Item_bool_func::val_int()
+#
+CREATE TABLE t (a INT) ENGINE=INNODB;
+SELECT SUM(a), ROWNUM() AS r FROM t HAVING r=1;
+SUM(a)	r
+NULL	1
+DROP TABLE t;
+# End of 10.5 tests

mysql-test/main/bool_innodb.test

@@ -0,0 +1,15 @@
+--source include/have_innodb.inc
+
+--echo #
+--echo # MDEV-35288: Assertion `!is_cond()' failed in
+--echo # virtual longlong Item_bool_func::val_int()
+--echo #
+
+CREATE TABLE t (a INT) ENGINE=INNODB;
+SELECT SUM(a), ROWNUM() AS r FROM t HAVING r=1;
+
+# Cleanup
+DROP TABLE t;
+
+
+--echo # End of 10.5 tests

sql/item_cmpfunc.h

@@ -248,6 +248,16 @@ class Item_bool_func :public Item_int_func,
     return val_bool();
   }
   bool val_bool() override= 0;
+  String *val_str(String *str) override final
+  {
+    DBUG_ASSERT(fixed());
+    bool res= val_bool();
+    if (null_value)
+      return 0;
+
+    str->set_int(res, false, collation.collation);
+    return str;
+  }
   bool fix_length_and_dec() override { decimals=0; max_length=1; return FALSE; }
   decimal_digits_t decimal_precision() const override { return 1; }
   bool need_parentheses_in_default() override { return true; }