From e81a28e57e6169c69f00bf787a699ef3bb30f68a Mon Sep 17 00:00:00 2001
From: Nathan Sobo <nathan@zed.dev>
Date: Wed, 12 May 2021 19:28:48 -0600
Subject: [PATCH 1/3] Remove dropped entities after every effect

---
 gpui/src/app.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/gpui/src/app.rs b/gpui/src/app.rs
index d539314bb7..469b9b8ac1 100644
--- a/gpui/src/app.rs
+++ b/gpui/src/app.rs
@@ -1064,8 +1064,8 @@ impl MutableAppContext {
                             self.focus(window_id, view_id);
                         }
                     }
-                } else {
                     self.remove_dropped_entities();
+                } else {
                     self.update_windows();
 
                     if self.pending_effects.is_empty() {

From 9dac491ed5f9b40e5f30056c6e7ea3fbddf31549 Mon Sep 17 00:00:00 2001
From: Nathan Sobo <nathan@zed.dev>
Date: Wed, 12 May 2021 19:29:17 -0600
Subject: [PATCH 2/3] Don't remove entities whose ref count has become positive
 again

---
 gpui/src/app.rs | 43 +++++++++++++++++++++++++++++++++----------
 1 file changed, 33 insertions(+), 10 deletions(-)

diff --git a/gpui/src/app.rs b/gpui/src/app.rs
index 469b9b8ac1..dab7508689 100644
--- a/gpui/src/app.rs
+++ b/gpui/src/app.rs
@@ -18,7 +18,7 @@ use smol::prelude::*;
 use std::{
     any::{type_name, Any, TypeId},
     cell::RefCell,
-    collections::{HashMap, HashSet, VecDeque},
+    collections::{hash_map::Entry, HashMap, HashSet, VecDeque},
     fmt::{self, Debug},
     hash::{Hash, Hasher},
     marker::PhantomData,
@@ -1988,7 +1988,7 @@ pub struct ModelHandle<T> {
 
 impl<T: Entity> ModelHandle<T> {
     fn new(model_id: usize, ref_counts: &Arc<Mutex<RefCounts>>) -> Self {
-        ref_counts.lock().inc_entity(model_id);
+        ref_counts.lock().inc_model(model_id);
         Self {
             model_id,
             model_type: PhantomData,
@@ -2089,7 +2089,7 @@ impl<T: Entity> ModelHandle<T> {
 
 impl<T> Clone for ModelHandle<T> {
     fn clone(&self) -> Self {
-        self.ref_counts.lock().inc_entity(self.model_id);
+        self.ref_counts.lock().inc_model(self.model_id);
         Self {
             model_id: self.model_id,
             model_type: PhantomData,
@@ -2186,7 +2186,7 @@ pub struct ViewHandle<T> {
 
 impl<T: View> ViewHandle<T> {
     fn new(window_id: usize, view_id: usize, ref_counts: &Arc<Mutex<RefCounts>>) -> Self {
-        ref_counts.lock().inc_entity(view_id);
+        ref_counts.lock().inc_view(window_id, view_id);
         Self {
             window_id,
             view_id,
@@ -2298,7 +2298,9 @@ impl<T: View> ViewHandle<T> {
 
 impl<T> Clone for ViewHandle<T> {
     fn clone(&self) -> Self {
-        self.ref_counts.lock().inc_entity(self.view_id);
+        self.ref_counts
+            .lock()
+            .inc_view(self.window_id, self.view_id);
         Self {
             window_id: self.window_id,
             view_id: self.view_id,
@@ -2380,7 +2382,9 @@ impl AnyViewHandle {
 
 impl Clone for AnyViewHandle {
     fn clone(&self) -> Self {
-        self.ref_counts.lock().inc_entity(self.view_id);
+        self.ref_counts
+            .lock()
+            .inc_view(self.window_id, self.view_id);
         Self {
             window_id: self.window_id,
             view_id: self.view_id,
@@ -2392,7 +2396,10 @@ impl Clone for AnyViewHandle {
 
 impl<T: View> From<&ViewHandle<T>> for AnyViewHandle {
     fn from(handle: &ViewHandle<T>) -> Self {
-        handle.ref_counts.lock().inc_entity(handle.view_id);
+        handle
+            .ref_counts
+            .lock()
+            .inc_view(handle.window_id, handle.view_id);
         AnyViewHandle {
             window_id: handle.window_id,
             view_id: handle.view_id,
@@ -2433,7 +2440,7 @@ pub struct AnyModelHandle {
 
 impl<T: Entity> From<ModelHandle<T>> for AnyModelHandle {
     fn from(handle: ModelHandle<T>) -> Self {
-        handle.ref_counts.lock().inc_entity(handle.model_id);
+        handle.ref_counts.lock().inc_model(handle.model_id);
         Self {
             model_id: handle.model_id,
             ref_counts: handle.ref_counts.clone(),
@@ -2542,8 +2549,24 @@ struct RefCounts {
 }
 
 impl RefCounts {
-    fn inc_entity(&mut self, entity_id: usize) {
-        *self.entity_counts.entry(entity_id).or_insert(0) += 1;
+    fn inc_model(&mut self, model_id: usize) {
+        match self.entity_counts.entry(model_id) {
+            Entry::Occupied(mut entry) => *entry.get_mut() += 1,
+            Entry::Vacant(entry) => {
+                entry.insert(1);
+                self.dropped_models.remove(&model_id);
+            }
+        }
+    }
+
+    fn inc_view(&mut self, window_id: usize, view_id: usize) {
+        match self.entity_counts.entry(view_id) {
+            Entry::Occupied(mut entry) => *entry.get_mut() += 1,
+            Entry::Vacant(entry) => {
+                entry.insert(1);
+                self.dropped_views.remove(&(window_id, view_id));
+            }
+        }
     }
 
     fn inc_value(&mut self, tag_type_id: TypeId, id: usize) {

From 493643c15fcf65f81912faf8e427acdcfd7ca004 Mon Sep 17 00:00:00 2001
From: Max Brunsfeld <maxbrunsfeld@gmail.com>
Date: Wed, 12 May 2021 19:45:45 -0700
Subject: [PATCH 3/3] Remove dropped entities even if there are no effects to
 flush

---
 gpui/src/app.rs | 1 +
 1 file changed, 1 insertion(+)

diff --git a/gpui/src/app.rs b/gpui/src/app.rs
index dab7508689..c4df05ffb8 100644
--- a/gpui/src/app.rs
+++ b/gpui/src/app.rs
@@ -1066,6 +1066,7 @@ impl MutableAppContext {
                     }
                     self.remove_dropped_entities();
                 } else {
+                    self.remove_dropped_entities();
                     self.update_windows();
 
                     if self.pending_effects.is_empty() {