From 4a648555ed7a61de615baad551bab8f34a5bad74 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Bla=C5=BE=20Hrastnik?= <blaz@mxxn.io>
Date: Thu, 8 Oct 2020 14:21:03 +0900
Subject: [PATCH] Don't try to compose zero-width deletes.

---
 helix-core/src/transaction.rs | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/helix-core/src/transaction.rs b/helix-core/src/transaction.rs
index 86fc0bc81..a84313b2f 100644
--- a/helix-core/src/transaction.rs
+++ b/helix-core/src/transaction.rs
@@ -439,7 +439,9 @@ impl Transaction {
                     }
                     acc.push(Operation::Insert(text));
                 }
-                None => acc.push(Operation::Delete(span)),
+                None if span > 0 => acc.push(Operation::Delete(span)),
+                // empty delete is useless
+                None => (),
             }
             last = to;
         }
@@ -577,7 +579,8 @@ mod test {
         let mut state = State::new("hello world!\ntest 123".into());
         let transaction = Transaction::change(
             &state,
-            vec![(6, 11, Some("void".into())), (12, 17, None)].into_iter(),
+            // (1, 1, None) is a useless 0-width delete
+            vec![(6, 11, Some("void".into())), (12, 17, None), (1, 1, None)].into_iter(),
         );
         transaction.apply(&mut state);
         assert_eq!(state.doc, Rope::from_str("hello void! 123"));