Merge pull request #1032 from zed-industries/clear-redo-stack-on-edit

Clear redo stack on edit

crates/editor/src/multi_buffer.rs

@@ -2479,6 +2479,7 @@ impl History {
                 self.undo_stack.pop();
                 false
             } else {
+                self.redo_stack.clear();
                 let transaction = self.undo_stack.last_mut().unwrap();
                 transaction.last_edit_at = now;
                 for (buffer_id, transaction_id) in buffer_transactions {
@@ -2511,6 +2512,7 @@ impl History {
         };
         if !transaction.buffer_transactions.is_empty() {
             self.undo_stack.push(transaction);
+            self.redo_stack.clear();
         }
     }
 
@@ -3935,6 +3937,16 @@ mod tests {
             buffer_1.update(cx, |buffer_1, cx| buffer_1.redo(cx));
             assert_eq!(multibuffer.read(cx).text(), "ABCD1234\nAB5678");
 
+            // Redo stack gets cleared after an edit.
+            now += 2 * group_interval;
+            multibuffer.start_transaction_at(now, cx);
+            multibuffer.edit([(0..0, "X")], cx);
+            multibuffer.end_transaction_at(now, cx);
+            assert_eq!(multibuffer.read(cx).text(), "XABCD1234\nAB5678");
+            multibuffer.redo(cx);
+            assert_eq!(multibuffer.read(cx).text(), "XABCD1234\nAB5678");
+            multibuffer.undo(cx);
+            assert_eq!(multibuffer.read(cx).text(), "ABCD1234\nAB5678");
             multibuffer.undo(cx);
             assert_eq!(multibuffer.read(cx).text(), "1234\n5678");
         });

crates/text/src/tests.rs

@@ -529,6 +529,16 @@ fn test_history() {
     assert!(buffer.end_transaction_at(now).is_none());
     buffer.undo();
     assert_eq!(buffer.text(), "12cde6");
+
+    // Redo stack gets cleared after performing an edit.
+    buffer.edit([(0..0, "X")]);
+    assert_eq!(buffer.text(), "X12cde6");
+    buffer.redo();
+    assert_eq!(buffer.text(), "X12cde6");
+    buffer.undo();
+    assert_eq!(buffer.text(), "12cde6");
+    buffer.undo();
+    assert_eq!(buffer.text(), "123456");
 }
 
 #[test]

crates/text/src/text.rs

@@ -216,6 +216,7 @@ impl History {
                 self.undo_stack.pop();
                 None
             } else {
+                self.redo_stack.clear();
                 let entry = self.undo_stack.last_mut().unwrap();
                 entry.last_edit_at = now;
                 Some(entry)
@@ -276,6 +277,7 @@ impl History {
             last_edit_at: now,
             suppress_grouping: false,
         });
+        self.redo_stack.clear();
     }
 
     fn push_undo(&mut self, op_id: clock::Local) {