fix string parsing for year

Author: parthchandra

native/spark-expr/src/conversion_funcs/string.rs

@@ -1103,31 +1103,31 @@ fn timestamp_parser<T: TimeZone>(
     // Define regex patterns and corresponding parsing functions
     let patterns = &[
         (
-            Regex::new(r"^\d{1,5}$").unwrap(),
+            Regex::new(r"^\d{4,5}$").unwrap(),
             parse_str_to_year_timestamp as fn(&str, &T) -> SparkResult<Option<i64>>,
         ),
         (
-            Regex::new(r"^\d{1,5}-\d{2}$").unwrap(),
+            Regex::new(r"^\d{4,5}-\d{2}$").unwrap(),
             parse_str_to_month_timestamp,
         ),
         (
-            Regex::new(r"^\d{1,5}-\d{2}-\d{2}$").unwrap(),
+            Regex::new(r"^\d{4,5}-\d{2}-\d{2}$").unwrap(),
             parse_str_to_day_timestamp,
         ),
         (
-            Regex::new(r"^\d{1,5}-\d{2}-\d{2}T\d{1,2}$").unwrap(),
+            Regex::new(r"^\d{4,5}-\d{2}-\d{2}T\d{1,2}$").unwrap(),
             parse_str_to_hour_timestamp,
         ),
         (
-            Regex::new(r"^\d{1,5}-\d{2}-\d{2}T\d{2}:\d{2}$").unwrap(),
+            Regex::new(r"^\d{4,5}-\d{2}-\d{2}T\d{2}:\d{2}$").unwrap(),
             parse_str_to_minute_timestamp,
         ),
         (
-            Regex::new(r"^\d{1,5}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}$").unwrap(),
+            Regex::new(r"^\d{4,5}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}$").unwrap(),
             parse_str_to_second_timestamp,
         ),
         (
-            Regex::new(r"^\d{1,5}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}\.\d{1,6}$").unwrap(),
+            Regex::new(r"^\d{4,5}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}\.\d{1,6}$").unwrap(),
             parse_str_to_microsecond_timestamp,
         ),
         (
@@ -1212,9 +1212,9 @@ fn date_parser(date_str: &str, eval_mode: EvalMode) -> SparkResult<Option<i32>>
     fn is_valid_digits(segment: i32, digits: usize) -> bool {
         // An integer is able to represent a date within [+-]5 million years.
         let max_digits_year = 7;
-        // year (segment 0) can be between 1 to 7 digits (Spark supports years like 100),
+        // year (segment 0) can be between 4 to 7 digits,
         // month and day (segment 1 and 2) can be between 1 to 2 digits
-        (segment == 0 && digits >= 1 && digits <= max_digits_year)
+        (segment == 0 && digits >= 4 && digits <= max_digits_year)
             || (segment != 0 && digits > 0 && digits <= 2)
     }