From d758d2b232e6501c9a53c375a69d2c6f7916903c Mon Sep 17 00:00:00 2001
From: rdb <git@rdb.name>
Date: Thu, 24 Oct 2024 16:41:56 +0200
Subject: [PATCH] pgui: Fix crash when PGEntry removes itself w/ background
 focus

Fixes #1650
---
 panda/src/pgui/pgItem.cxx | 30 ++++++++++++++++++++++--------
 1 file changed, 22 insertions(+), 8 deletions(-)

diff --git a/panda/src/pgui/pgItem.cxx b/panda/src/pgui/pgItem.cxx
index 1ad3441a63..e955613362 100644
--- a/panda/src/pgui/pgItem.cxx
+++ b/panda/src/pgui/pgItem.cxx
@@ -784,9 +784,14 @@ move(const MouseWatcherParameter &param) {
  */
 void PGItem::
 background_press(const MouseWatcherParameter &param) {
-  for (PGItem *item : _background_focus) {
+  // We have to be careful, because objects may remove themselves from the set
+  // while we're iterating over it.
+  auto it = _background_focus.begin();
+  while (it != _background_focus.end()) {
+    PGItem *item = *it++;
     if (!item->get_focus()) {
-      item->press(param, true);
+      PT(PGItem) item_ref(item);
+      item_ref->press(param, true);
     }
   }
 }
@@ -796,9 +801,12 @@ background_press(const MouseWatcherParameter &param) {
  */
 void PGItem::
 background_release(const MouseWatcherParameter &param) {
-  for (PGItem *item : _background_focus) {
+  auto it = _background_focus.begin();
+  while (it != _background_focus.end()) {
+    PGItem *item = *it++;
     if (!item->get_focus()) {
-      item->release(param, true);
+      PT(PGItem) item_ref(item);
+      item_ref->release(param, true);
     }
   }
 }
@@ -808,9 +816,12 @@ background_release(const MouseWatcherParameter &param) {
  */
 void PGItem::
 background_keystroke(const MouseWatcherParameter &param) {
-  for (PGItem *item : _background_focus) {
+  auto it = _background_focus.begin();
+  while (it != _background_focus.end()) {
+    PGItem *item = *it++;
     if (!item->get_focus()) {
-      item->keystroke(param, true);
+      PT(PGItem) item_ref(item);
+      item_ref->keystroke(param, true);
     }
   }
 }
@@ -820,9 +831,12 @@ background_keystroke(const MouseWatcherParameter &param) {
  */
 void PGItem::
 background_candidate(const MouseWatcherParameter &param) {
-  for (PGItem *item : _background_focus) {
+  auto it = _background_focus.begin();
+  while (it != _background_focus.end()) {
+    PGItem *item = *it++;
     if (!item->get_focus()) {
-      item->candidate(param, true);
+      PT(PGItem) item_ref(item);
+      item_ref->candidate(param, true);
     }
   }
 }