MDEV-8205 timediff returns null when comparing decimal time to time string value

mysql-test/r/func_time.result

@@ -2701,3 +2701,45 @@ id	date1	date2	DATE_ADD(a.date1,INTERVAL -10 DAY)	TO_DAYS(a.date1)-10
 17	NULL	NULL	NULL	NULL
 18	2010-10-13	2010-10-03	2010-10-03	734413
 DROP TABLE t1;
+#
+# Start of 10.0 tests
+#
+#
+# MDEV-8205 timediff returns null when comparing decimal time to time string value
+#
+SELECT
+TIMEDIFF('2014-01-01 00:00:00' , '2014-01-01 01:00:00' ) AS str_str,
+TIMEDIFF('2014-01-01 00:00:00' , 20140101010000.000    ) AS str_dec,
+TIMEDIFF(20140101000000.000    , 20140101010000.000    ) AS dec_dec,
+TIMEDIFF(20140101000000.000    , '2014-01-01 01:00:00' ) AS dec_str;
+str_str	str_dec	dec_dec	dec_str
+-01:00:00	-01:00:00.000	-01:00:00.000	-01:00:00.000
+SELECT
+TIMEDIFF('2014-01-01 00:00:00' , '2014-01-02 01:00:00' ) AS str_str,
+TIMEDIFF('2014-01-01 00:00:00' , 20140102010000.000    ) AS str_dec,
+TIMEDIFF(20140101000000.000    , 20140102010000.000    ) AS dec_dec,
+TIMEDIFF(20140101000000.000    , '2014-01-02 01:00:00' ) AS dec_str;
+str_str	str_dec	dec_dec	dec_str
+-25:00:00	-25:00:00.000	-25:00:00.000	-25:00:00.000
+SELECT
+TIMEDIFF('2014-01-01 00:00:00' , '2014-02-02 01:00:00' ) AS str_str,
+TIMEDIFF('2014-01-01 00:00:00' , 20140202010000.000    ) AS str_dec,
+TIMEDIFF(20140101000000.000    , 20140202010000.000    ) AS dec_dec,
+TIMEDIFF(20140101000000.000    , '2014-02-02 01:00:00' ) AS dec_str;
+str_str	str_dec	dec_dec	dec_str
+-769:00:00	-769:00:00.000	-769:00:00.000	-769:00:00.000
+SELECT
+TIMEDIFF('2014-01-01 00:00:00' , '2014-03-02 01:00:00' ) AS str_str,
+TIMEDIFF('2014-01-01 00:00:00' , 20140302010000.000    ) AS str_dec,
+TIMEDIFF(20140101000000.000    , 20140302010000.000    ) AS dec_dec,
+TIMEDIFF(20140101000000.000    , '2014-03-02 01:00:00' ) AS dec_str;
+str_str	str_dec	dec_dec	dec_str
+-838:59:59	-838:59:59.999	-838:59:59.999	-838:59:59.999
+Warnings:
+Warning	1292	Truncated incorrect time value: '-1441:00:00'
+Warning	1292	Truncated incorrect time value: '-1441:00:00'
+Warning	1292	Truncated incorrect time value: '-1441:00:00'
+Warning	1292	Truncated incorrect time value: '-1441:00:00'
+#
+# End of 10.0 tests
+#

mysql-test/t/func_time.test

@@ -1649,3 +1649,44 @@ INSERT INTO t1 VALUES (17, NULL);
 INSERT INTO t1 VALUES (18, '2010-10-13');
 SELECT a.id,a.date1,FROM_DAYS(TO_DAYS(a.date1)-10) as date2, DATE_ADD(a.date1,INTERVAL -10 DAY),TO_DAYS(a.date1)-10 FROM t1 a ORDER BY a.id;
 DROP TABLE t1;
+
+
+--echo #
+--echo # Start of 10.0 tests
+--echo #
+
+--echo #
+--echo # MDEV-8205 timediff returns null when comparing decimal time to time string value
+--echo #
+
+# 1h difference
+SELECT
+  TIMEDIFF('2014-01-01 00:00:00' , '2014-01-01 01:00:00' ) AS str_str,
+  TIMEDIFF('2014-01-01 00:00:00' , 20140101010000.000    ) AS str_dec,
+  TIMEDIFF(20140101000000.000    , 20140101010000.000    ) AS dec_dec,
+  TIMEDIFF(20140101000000.000    , '2014-01-01 01:00:00' ) AS dec_str;
+
+# 1D1h difference
+SELECT
+  TIMEDIFF('2014-01-01 00:00:00' , '2014-01-02 01:00:00' ) AS str_str,
+  TIMEDIFF('2014-01-01 00:00:00' , 20140102010000.000    ) AS str_dec,
+  TIMEDIFF(20140101000000.000    , 20140102010000.000    ) AS dec_dec,
+  TIMEDIFF(20140101000000.000    , '2014-01-02 01:00:00' ) AS dec_str;
+
+# 1M1D1h difference
+SELECT
+  TIMEDIFF('2014-01-01 00:00:00' , '2014-02-02 01:00:00' ) AS str_str,
+  TIMEDIFF('2014-01-01 00:00:00' , 20140202010000.000    ) AS str_dec,
+  TIMEDIFF(20140101000000.000    , 20140202010000.000    ) AS dec_dec,
+  TIMEDIFF(20140101000000.000    , '2014-02-02 01:00:00' ) AS dec_str;
+
+# 2M1D1h difference
+SELECT
+  TIMEDIFF('2014-01-01 00:00:00' , '2014-03-02 01:00:00' ) AS str_str,
+  TIMEDIFF('2014-01-01 00:00:00' , 20140302010000.000    ) AS str_dec,
+  TIMEDIFF(20140101000000.000    , 20140302010000.000    ) AS dec_dec,
+  TIMEDIFF(20140101000000.000    , '2014-03-02 01:00:00' ) AS dec_str;
+
+--echo #
+--echo # End of 10.0 tests
+--echo #

sql-common/my_time.c

@@ -1314,16 +1314,8 @@ int number_to_time(my_bool neg, ulonglong nr, ulong sec_part,
                    MYSQL_TIME *ltime, int *was_cut)
 {
   if (nr > 9999999 && nr < 99991231235959ULL && neg == 0)
-  {
-    if (number_to_datetime(nr, sec_part, ltime,
-                           TIME_INVALID_DATES, was_cut) < 0)
-      return -1;
-
-    ltime->year= ltime->month= ltime->day= 0;
-    ltime->time_type= MYSQL_TIMESTAMP_TIME;
-    *was_cut= MYSQL_TIME_NOTE_TRUNCATED;
-    return 0;
-  }
+    return number_to_datetime(nr, sec_part, ltime,
+                              TIME_INVALID_DATES, was_cut) < 0 ? -1 : 0;
 
   *was_cut= 0;
   ltime->year= ltime->month= ltime->day= 0;