Fix some incorrect parsing of time with time zone strings

When parsing a timetz string with a dynamic timezone abbreviation or a
timezone not specified, it was possible to generate incorrect timestamps
based on a date which uses some non-initialized variables if the input
string did not specify fully a date to parse.  This is already checked
when a full timezone spec is included in the input string, but the two
other cases mentioned above missed the same checks.

This gets fixed by generating an error as this input is invalid, or in
short when a date is not fully specified.

Valgrind was complaining about this problem.

Bug: #15910
Author: Alexander Lakhin
Discussion: https://postgr.es/m/15910-2eba5106b9aa0c61@postgresql.org
Backpatch-through: 9.4

src/backend/utils/adt/datetime.c

@@ -2280,6 +2280,9 @@ DecodeTimeOnly(char **field, int *ftype, int nf,
 			GetCurrentDateTime(tmp);
 		else
 		{
+			/* a date has to be specified */
+			if ((fmask & DTK_DATE_M) != DTK_DATE_M)
+				return DTERR_BAD_FORMAT;
 			tmp->tm_year = tm->tm_year;
 			tmp->tm_mon = tm->tm_mon;
 			tmp->tm_mday = tm->tm_mday;
@@ -2307,6 +2310,9 @@ DecodeTimeOnly(char **field, int *ftype, int nf,
 			GetCurrentDateTime(tmp);
 		else
 		{
+			/* a date has to be specified */
+			if ((fmask & DTK_DATE_M) != DTK_DATE_M)
+				return DTERR_BAD_FORMAT;
 			tmp->tm_year = tm->tm_year;
 			tmp->tm_mon = tm->tm_mon;
 			tmp->tm_mday = tm->tm_mday;

src/test/regress/expected/timetz.out

@@ -19,6 +19,16 @@ INSERT INTO TIMETZ_TBL VALUES ('15:36:39 America/New_York');
 ERROR:  invalid input syntax for type time with time zone: "15:36:39 America/New_York"
 LINE 1: INSERT INTO TIMETZ_TBL VALUES ('15:36:39 America/New_York');
                                        ^
+-- this should fail (timezone not specified without a date)
+INSERT INTO TIMETZ_TBL VALUES ('15:36:39 m2');
+ERROR:  invalid input syntax for type time with time zone: "15:36:39 m2"
+LINE 1: INSERT INTO TIMETZ_TBL VALUES ('15:36:39 m2');
+                                       ^
+-- this should fail (dynamic timezone abbreviation without a date)
+INSERT INTO TIMETZ_TBL VALUES ('15:36:39 MSK m2');
+ERROR:  invalid input syntax for type time with time zone: "15:36:39 MSK m2"
+LINE 1: INSERT INTO TIMETZ_TBL VALUES ('15:36:39 MSK m2');
+                                       ^
 SELECT f1 AS "Time TZ" FROM TIMETZ_TBL;
     Time TZ     
 ----------------

src/test/regress/sql/timetz.sql

@@ -19,6 +19,11 @@ INSERT INTO TIMETZ_TBL VALUES ('2003-03-07 15:36:39 America/New_York');
 INSERT INTO TIMETZ_TBL VALUES ('2003-07-07 15:36:39 America/New_York');
 -- this should fail (the timezone offset is not known)
 INSERT INTO TIMETZ_TBL VALUES ('15:36:39 America/New_York');
+-- this should fail (timezone not specified without a date)
+INSERT INTO TIMETZ_TBL VALUES ('15:36:39 m2');
+-- this should fail (dynamic timezone abbreviation without a date)
+INSERT INTO TIMETZ_TBL VALUES ('15:36:39 MSK m2');
+
 
 SELECT f1 AS "Time TZ" FROM TIMETZ_TBL;