Bug#19904: UDF: not initialized *is_null per row

The is_null value was initialized once and thereafter only set to indicate
NULL, and never unset to indicate not-NULL.

Now set is_null to false, in addition to only setting it to true when the value 
in question is null.


mysql-test/r/udf.result:
  Add result.
mysql-test/t/udf.test:
  Add test.
sql/sql_udf.h:
  Initialize is_null to false before trying to use it, so that historical NULLs
  don't affect our operation.

1 files changed, 18 insertions, 0 deletions

diff --git a/mysql-test/r/udf.result b/mysql-test/r/udf.result
index be52fd7f87c..484c42c41bf 100644
--- a/mysql-test/r/udf.result
+++ b/mysql-test/r/udf.result
@@ -76,6 +76,24 @@ call XXX2();
 metaphon(testval)
 HL
 drop procedure xxx2;
+CREATE TABLE bug19904(n INT, v varchar(10));
+INSERT INTO bug19904 VALUES (1,'one'),(2,'two'),(NULL,NULL),(3,'three'),(4,'four');
+SELECT myfunc_double(n) AS f FROM bug19904;
+f
+49.00
+50.00
+NULL
+51.00
+52.00
+SELECT metaphon(v) AS f FROM bug19904;
+f
+ON
+TW
+NULL
+0R
+FR
+DROP TABLE bug19904;
+End of 5.0 tests.
 DROP FUNCTION metaphon;
 DROP FUNCTION myfunc_double;
 DROP FUNCTION myfunc_nonexist;