Fix added lines overlapping unblamed hunk's start

Author: cruessler

gix-blame/tests/blame.rs

@@ -492,25 +492,30 @@ fn process_change(
                     (None, new_change)
                 }
                 (false, true) => {
-                    *offset_in_destination += added.end - added.start;
-                    *offset_in_destination -= number_of_lines_deleted;
-
                     //    <------->  (hunk)
                     // <------>      (added)
                     //    <--->      (blamed)
                     //         <-->  (new hunk)
-                    new_hunks_to_blame.push(UnblamedHunk::new(
-                        (added.end + 1)..hunk.range_in_blamed_file.end,
-                        Offset::Added(hunk.range_in_destination.start - hunk.range_in_blamed_file.start),
-                    ));
 
                     lines_blamed.push(BlameEntry::with_offset(
                         hunk.range_in_destination.start..added.end,
                         suspect,
-                        *offset_in_destination,
+                        hunk.offset(),
                     ));
 
-                    (None, None)
+                    *offset_in_destination += added.end - added.start;
+                    *offset_in_destination -= number_of_lines_deleted;
+
+                    let new_hunk = if hunk.range_in_destination.end > added.end {
+                        Some(UnblamedHunk::from_destination(
+                            added.end..hunk.range_in_destination.end,
+                            hunk.offset(),
+                        ))
+                    } else {
+                        None
+                    };
+
+                    (new_hunk, None)
                 }
                 (false, false) => {
                     // Any of the following cases are handled by this branch:
@@ -1355,6 +1360,37 @@ fn process_change_works_added_hunk_8() {
     assert_eq!(offset_in_destination, Offset::Added(2));
 }
 
+#[test]
+fn process_change_works_added_hunk_9() {
+    let mut lines_blamed: Vec<BlameEntry> = vec![];
+    let mut new_hunks_to_blame: Vec<UnblamedHunk> = vec![];
+    let mut offset_in_destination: Offset = Offset::Added(0);
+    let suspect = ObjectId::null(gix_hash::Kind::Sha1);
+
+    let (hunk, change) = process_change(
+        &mut lines_blamed,
+        &mut new_hunks_to_blame,
+        &mut offset_in_destination,
+        suspect,
+        // range_in_destination: 21..22
+        Some(UnblamedHunk::new(23..24, Offset::Added(2))),
+        Some(Change::Added(18..22, 3)),
+    );
+
+    assert_eq!(hunk, None);
+    assert_eq!(change, None);
+    assert_eq!(
+        lines_blamed,
+        vec![BlameEntry {
+            range_in_blamed_file: 23..24,
+            range_in_original_file: 21..22,
+            commit_id: suspect
+        }]
+    );
+    assert_eq!(new_hunks_to_blame, vec![]);
+    assert_eq!(offset_in_destination, Offset::Added(1));
+}
+
 #[test]
 fn process_change_works_no_overlap() {
     let mut lines_blamed: Vec<BlameEntry> = vec![];