From 3b01247df945ca4f71a23683096d761b2bc65da9 Mon Sep 17 00:00:00 2001
From: Mattias Andersson <mandersson444@gmail.com>
Date: Thu, 13 Feb 2014 10:41:24 +0100
Subject: [PATCH] Iterate over a copy of the parents container since we are
 removing elements from the original.

---
 src/library/librarymodel.cpp | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/src/library/librarymodel.cpp b/src/library/librarymodel.cpp
index 1e1a9ece8..3e048da67 100644
--- a/src/library/librarymodel.cpp
+++ b/src/library/librarymodel.cpp
@@ -380,7 +380,11 @@ void LibraryModel::SongsDeleted(const SongList& songs) {
   // Now delete empty parents
   QSet<QString> divider_keys;
   while (!parents.isEmpty()) {
-    for (LibraryItem* node : parents) {
+    // Since we are going to remove elements from the container, we
+    // need a copy to iterate over. If we iterate over the original,
+    // the behavior will be undefined.
+    QSet<LibraryItem*> parents_copy = parents;
+    for (LibraryItem* node : parents_copy) {
       parents.remove(node);
       if (node->children.count() != 0) continue;