Fix AM/PM and timezone parsing for DATETIMEOFFSET (#3775)

The clean_input_str() function, while removing leading spaces,
incorrectly removes the space between AM/PM and timezone indicators
(e.g., converting "PM -07:00" to "PM-07:00"), causing the subsequent
date parser function `ParseDateTime` to fail to recognize the components
completely.

Modified the space-handling logic in clean_input_str() to preserve
spaces before timezone indicators in datetimeoffset context, provided
that the time information has already been seen (after encountering
colons in the input string). This ensures the timezone offset remains
properly separated from the preceding time information, allowing
`ParseDateTime` to correctly parse both components.

Task: BABEL-5832
Signed-off-by: Manisha Deshpande <mmdeshp@amazon.com>

Author: manisha-deshpande

contrib/babelfishpg_common/src/datetime.c

@@ -290,6 +290,10 @@ clean_input_str(char *str, bool *contains_extra_spaces, DateTimeContext context)
 				(context != DATE_TIME && (str[i] == '.' || str[i] == '/' 
 				|| str[i] == '+' || str[i] == '-')))
 		{
+			/* For datetimeoffset, preserve space before timezone indicator (+/-) */
+			if (context == DATE_TIME_OFFSET && (str[i] == '+' || str[i] == '-') && num_colons > 0)
+				result[j++] = ' ';
+
 			result[j] = str[i];
 			j++;
 		}

test/JDBC/expected/babel_datetimeoffset.out

@@ -330,6 +330,43 @@ datetimeoffset
 ~~END~~
 
 
+-- Test AM/PM notation
+select CAST('2025-05-20 02:30:20.123456 PM -07:00' as DATETIMEOFFSET);
+go
+~~START~~
+datetimeoffset
+2025-05-20 14:30:20.1234560 -07:00
+~~END~~
+
+select CAST('2025-05-20 02:30:20.123456 PM-07:0' as DATETIMEOFFSET);
+go
+~~START~~
+datetimeoffset
+2025-05-20 14:30:20.1234560 -07:00
+~~END~~
+
+select CAST('2025-05- 20    02:30:20.123456     PM    -07:00' as DATETIMEOFFSET(4));
+go
+~~START~~
+datetimeoffset
+2025-05-20 14:30:20.1235 -07:00
+~~END~~
+
+select CAST('2025-05-20 02:30:20.123456 AM +07:59' as DATETIMEOFFSET);
+go
+~~START~~
+datetimeoffset
+2025-05-20 02:30:20.1234560 +07:59
+~~END~~
+
+    -- out of range
+select CAST('2025-05-20 02:30:20.123456 AM +07:79' as DATETIMEOFFSET);
+go
+~~ERROR (Code: 33557097)~~
+
+~~ERROR (Message: time zone displacement out of range: "2025-05-20 02:30:20.123456 AM +07:79")~~
+
+
 -- Test type cast to/from other time formats
 -- Test datetime/dateime2
 select CAST(CAST('2020-03-15 23:59:29.99' AS datetime) AS datetimeoffset);

test/JDBC/input/babel_datetimeoffset.sql

@@ -110,6 +110,19 @@ go
 select CAST('2079-06-06 23:59:29.123456 -9:30' AS datetimeoffset(7));
 go
 
+-- Test AM/PM notation
+select CAST('2025-05-20 02:30:20.123456 PM -07:00' as DATETIMEOFFSET);
+go
+select CAST('2025-05-20 02:30:20.123456 PM-07:0' as DATETIMEOFFSET);
+go
+select CAST('2025-05- 20    02:30:20.123456     PM    -07:00' as DATETIMEOFFSET(4));
+go
+select CAST('2025-05-20 02:30:20.123456 AM +07:59' as DATETIMEOFFSET);
+go
+    -- out of range
+select CAST('2025-05-20 02:30:20.123456 AM +07:79' as DATETIMEOFFSET);
+go
+
 -- Test type cast to/from other time formats
 -- Test datetime/dateime2
 select CAST(CAST('2020-03-15 23:59:29.99' AS datetime) AS datetimeoffset);