fix: correctly parse raw dates with negative timezone offsets

Author: willstott101

git-date/src/parse.rs

@@ -72,10 +72,13 @@ pub(crate) mod function {
         if offset.len() != 5 {
             return None;
         }
-        let sign = if &offset[..1] == "-" { Sign::Plus } else { Sign::Minus };
+        let sign = if &offset[..1] == "-" { Sign::Minus } else { Sign::Plus };
         let hours: i32 = offset[1..3].parse().ok()?;
         let minutes: i32 = offset[3..5].parse().ok()?;
-        let offset_in_seconds = hours * 3600 + minutes * 60;
+        let mut offset_in_seconds = hours * 3600 + minutes * 60;
+        if sign == Sign::Minus {
+            offset_in_seconds *= -1;
+        };
         let time = Time {
             seconds_since_unix_epoch,
             offset_in_seconds,

git-date/tests/time/parse.rs

@@ -40,6 +40,30 @@ fn rfc2822() {
     );
 }
 
+
+#[test]
+fn raw() {
+    assert_eq!(
+        git_date::parse("1660874655 +0800", None).expect("parsed raw string"),
+        Time {
+            seconds_since_unix_epoch: 1660874655,
+            offset_in_seconds: 28800,
+            sign: Sign::Plus,
+        },
+        "could not parse with raw format"
+    );
+
+    assert_eq!(
+        git_date::parse("1660874655 -0800", None).expect("parsed raw string"),
+        Time {
+            seconds_since_unix_epoch: 1660874655,
+            offset_in_seconds: -28800,
+            sign: Sign::Minus,
+        },
+        "could not parse with raw format"
+    );
+}
+
 #[test]
 fn invalid_dates_can_be_produced_without_current_time() {
     assert!(matches!(