Fix closing buffer with custom keymap (#3633)

* Fix closing buffer with custom keymap

* Add comment explaining if

helix-term/src/ui/editor.rs

@@ -1263,6 +1263,8 @@ impl Component for EditorView {
                 if cx.editor.should_close() {
                     return EventResult::Ignored(None);
                 }
+                // if the focused view still exists and wasn't closed
+                if cx.editor.tree.contains(focus) {
                     let config = cx.editor.config();
                     let mode = cx.editor.mode();
                     let view = cx.editor.tree.get_mut(focus);
@@ -1275,6 +1277,7 @@ impl Component for EditorView {
                     if mode != Mode::Insert {
                         doc.append_changes_to_history(view.id);
                     }
+                }
 
                 EventResult::Consumed(callback)
             }

helix-view/src/tree.rs

@@ -270,10 +270,18 @@ impl Tree {
             })
     }
 
+    /// Get reference to a [`view`] by index.
+    /// # Panics
+    ///
+    /// Panics if `index` is not in self.nodes, or if the node's content is not [`Content::View`] . This can be checked with [`contains`]
     pub fn get(&self, index: ViewId) -> &View {
         self.try_get(index).unwrap()
     }
 
+    /// Try to get reference to a [`view`] by index. Returns `None` if node content is not a [`Content::View`]
+    /// # Panics
+    ///
+    /// Panics if `index` is not in self.nodes. This can be checked with [`Self::contains`]
     pub fn try_get(&self, index: ViewId) -> Option<&View> {
         match &self.nodes[index] {
             Node {
@@ -284,6 +292,10 @@ impl Tree {
         }
     }
 
+    /// Get a mutable reference to a [`view`] by index.
+    /// # Panics
+    ///
+    /// Panics if `index` is not in self.nodes, or if the node's content is not [`Content::View`] . This can be checked with [`Self::contains`]
     pub fn get_mut(&mut self, index: ViewId) -> &mut View {
         match &mut self.nodes[index] {
             Node {
@@ -294,6 +306,11 @@ impl Tree {
         }
     }
 
+    /// Check if tree contains a [`Node`] with a given index.
+    pub fn contains(&self, index: ViewId) -> bool {
+        self.nodes.contains_key(index)
+    }
+
     pub fn is_empty(&self) -> bool {
         match &self.nodes[self.root] {
             Node {