Fix chunk navigation label reset on Insert/Delete chunks (#27)

* Fix chunk navigation label reset on Insert/Delete chunks

The cursor_position_notify handler (added for cursor tracking) overwrites
current_chunk via chunk_at_cursor() whenever the cursor moves. For Insert
chunks where start_a == end_a, the zero-length range check fails and
current_chunk is set to None, causing the label to show "3 changes"
instead of "Change 3 of 3".

Fix by setting current_chunk AFTER place_cursor_at_line calls so the
correct value persists after the cursor tracking handler runs.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

* bump to 0.5.2

---------

Co-authored-by: Claude Opus 4.6 <noreply@anthropic.com>

Author: joske

Cargo.lock

@@ -1,6 +1,6 @@
 [package]
 name = "mergers"
-version = "0.5.1"
+version = "0.5.2"
 edition = "2024"
 description = "A visual diff and merge tool for files and directories"
 license = "GPL-2.0"

Cargo.toml

@@ -1537,12 +1537,14 @@ pub(super) fn navigate_chunk(
     };
 
     if let Some(idx) = diff_state::find_next_chunk(chunks, cursor_line, direction, side, wrap) {
-        current_chunk.set(Some(idx));
         let chunk = &chunks[idx];
         scroll_to_line(left_tv, left_buf, chunk.start_a, left_scroll);
         scroll_to_line(right_tv, right_buf, chunk.start_b, right_scroll);
         place_cursor_at_line(left_buf, chunk.start_a);
         place_cursor_at_line(right_buf, chunk.start_b);
+        // Set current_chunk AFTER placing cursors, because cursor_position_notify
+        // handlers may overwrite it (e.g. for Insert chunks with zero-length ranges).
+        current_chunk.set(Some(idx));
     }
 }
 

src/ui/common.rs

@@ -832,7 +832,6 @@ fn build_merge_view(
             }
         };
         if let Some((idx, is_right)) = found {
-            cur.set(Some((idx, is_right)));
             if is_right {
                 // right_chunks: A = middle, B = right
                 let chunk = &rch[idx];
@@ -852,6 +851,9 @@ fn build_merge_view(
                 // Right pane: no corresponding line — just scroll to middle line
                 scroll_to_line(rtv, rb, chunk.start_b, r_scroll);
             }
+            // Set current_chunk AFTER placing cursors, because cursor_position_notify
+            // handlers may overwrite it (e.g. for Insert chunks with zero-length ranges).
+            cur.set(Some((idx, is_right)));
             lf.queue_draw();
             mf.queue_draw();
             rf.queue_draw();