From b7329ee9047d47d80f3b3c8fd41f09f6c5236ab7 Mon Sep 17 00:00:00 2001
From: MarekSpodBiedry <73122968+MarekSpodBiedry@users.noreply.github.com>
Date: Tue, 13 Oct 2026 17:50:42 +0200
Subject: [PATCH] Keep unrelated overlapping clips untouched when deleting
 fades (#449)

---
 crates/engine/src/edit.rs | 26 ++++++++++++++++++++++++--
 1 file changed, 24 insertions(+), 2 deletions(-)

diff --git a/crates/engine/src/edit.rs b/crates/engine/src/edit.rs
index 5531953d..b26e14d8 100644
--- a/crates/engine/src/edit.rs
+++ b/crates/engine/src/edit.rs
@@ -812,8 +812,10 @@ pub fn create_fades(s: &mut Session, track: TrackId, range: Range, shape: FadeSh
 pub fn delete_fades(s: &mut Session, track: TrackId, range: Range) -> usize {
     let Some(pl) = s.track_mut(track).and_then(|t| t.playlist_mut()) else { return 0 };
     let mut n = 0;
+    let mut touched: HashSet<ClipId> = HashSet::new();
     for c in &mut pl.clips {
         if c.range().overlaps(&range) || (range.is_empty() && c.range().contains(range.start)) {
+            touched.insert(c.id);
             if c.fade_in.len > 0 || c.fade_out.len > 0 {
                 n += 1;
             }
@@ -821,11 +823,12 @@ pub fn delete_fades(s: &mut Session, track: TrackId, range: Range) -> usize {
             c.fade_out = Fade::default();
         }
     }
-    // Overlapping (crossfaded) neighbours are trimmed back to the midpoint.
+    // Overlapping (crossfaded) neighbours in the range are trimmed back to the midpoint; other overlaps stay as they are.
     pl.sort();
     for i in 0..pl.clips.len().saturating_sub(1) {
         let (Some(a_end), Some(b_start)) = (pl.clips.get(i).map(Clip::end), pl.clips.get(i + 1).map(|c| c.start)) else { continue };
-        if a_end > b_start {
+        let in_range = pl.clips.get(i).is_some_and(|a| touched.contains(&a.id)) || pl.clips.get(i + 1).is_some_and(|b| touched.contains(&b.id));
+        if in_range && a_end > b_start {
             let mid = b_start + (a_end - b_start) / 2;
             if let Some(a) = pl.clips.get_mut(i) {
                 a.trim_end_to(mid);
@@ -1041,4 +1044,23 @@ mod tests {
         s.find_clip_mut(id).unwrap().time_locked = true;
         assert_eq!(move_clips(&mut s, &[id], 500, &[]), 0);
     }
+
+    #[test]
+    fn delete_fades_leaves_unrelated_overlaps_alone() {
+        let (mut s, t) = session_with_clip();
+        let ids: Vec<ClipId> = (0..4).map(|_| s.new_clip_id()).collect();
+        if let Some(pl) = s.track_mut(t).and_then(|t| t.playlist_mut()) {
+            pl.clips.clear();
+            for (id, start, len) in [(ids[0], 0, 1100), (ids[1], 1000, 1000), (ids[2], 5000, 1100), (ids[3], 6000, 1000)] {
+                let mut c = Clip::audio(id, "c", SourceId(500), start, start, len);
+                c.fade_in = Fade { len: 100, shape: FadeShape::Linear, curvature: 0.0 };
+                c.fade_out = Fade { len: 100, shape: FadeShape::Linear, curvature: 0.0 };
+                pl.clips.push(c);
+            }
+        }
+        assert_eq!(delete_fades(&mut s, t, Range::new(900, 1200)), 2);
+        assert_eq!(clips(&s, t), vec![(0, 1050, 0), (1050, 950, 1050), (5000, 1100, 5000), (6000, 1000, 6000)]);
+        let c = s.track(t).unwrap().clips();
+        assert_eq!((c[1].fade_in.len, c[2].fade_out.len, c[3].fade_in.len), (0, 100, 100));
+    }
 }