MDEV-10468 Assertion `nr >= 0.0' failed in Item_sum_std::val_real()

Author: Alexander Barkov

mysql-test/r/func_group.result

@@ -2297,3 +2297,15 @@ FROM t1;
 C_1	C_2	C_3
 NULL	100	200
 DROP TABLE t1;
+#
+# MDEV-10468 Assertion `nr >= 0.0' failed in Item_sum_std::val_real()
+#
+SELECT STDDEV_POP(f) FROM (SELECT "1e+309" AS f UNION SELECT "-1e+309" AS f) tbl;
+STDDEV_POP(f)
+1.7976931348623157e308
+Warnings:
+Warning	1292	Truncated incorrect DOUBLE value: '1e+309'
+Warning	1292	Truncated incorrect DOUBLE value: '-1e+309'
+SELECT STDDEV(f) FROM (SELECT 1.7976931348623157e+308 AS f UNION SELECT -1.7976931348623157e+308 AS f) tbl;
+STDDEV(f)
+1.7976931348623157e308

mysql-test/t/func_group.test

@@ -1590,3 +1590,9 @@ SELECT
   SUM(data3) AS C_3
 FROM t1;
 DROP TABLE t1;
+
+--echo #
+--echo # MDEV-10468 Assertion `nr >= 0.0' failed in Item_sum_std::val_real()
+--echo #
+SELECT STDDEV_POP(f) FROM (SELECT "1e+309" AS f UNION SELECT "-1e+309" AS f) tbl;
+SELECT STDDEV(f) FROM (SELECT 1.7976931348623157e+308 AS f UNION SELECT -1.7976931348623157e+308 AS f) tbl;

sql/item_sum.cc

@@ -1762,6 +1762,8 @@ double Item_sum_std::val_real()
 {
   DBUG_ASSERT(fixed == 1);
   double nr= Item_sum_variance::val_real();
+  if (my_isinf(nr))
+    return DBL_MAX;
   DBUG_ASSERT(nr >= 0.0);
   return sqrt(nr);
 }