From 5eef2b910521a5df917574d1cde7f63502311dca Mon Sep 17 00:00:00 2001
From: Maxime Coste <mawww@kakoune.org>
Date: Mon, 20 Feb 2017 13:44:08 +0000
Subject: [PATCH] Correctly handle mutation of the watcher list while iterating
 on them

Fixes #1227
---
 src/option_manager.cc                              |  9 +++++++--
 test/regression/1227-segfault-on-option-access/cmd |  1 +
 test/regression/1227-segfault-on-option-access/in  |  1 +
 test/regression/1227-segfault-on-option-access/out |  1 +
 test/regression/1227-segfault-on-option-access/rc  | 10 ++++++++++
 5 files changed, 20 insertions(+), 2 deletions(-)
 create mode 100644 test/regression/1227-segfault-on-option-access/cmd
 create mode 100644 test/regression/1227-segfault-on-option-access/in
 create mode 100644 test/regression/1227-segfault-on-option-access/out
 create mode 100644 test/regression/1227-segfault-on-option-access/rc

diff --git a/src/option_manager.cc b/src/option_manager.cc
index c8722c15..eb50bfcb 100644
--- a/src/option_manager.cc
+++ b/src/option_manager.cc
@@ -108,8 +108,13 @@ void OptionManager::on_option_changed(const Option& option)
         find_option(m_options, option.name()) != m_options.end())
         return;
 
-    for (auto watcher : m_watchers)
-        watcher->on_option_changed(option);
+    // The watcher list might get mutated during calls to on_option_changed
+    auto watchers = m_watchers;
+    for (auto* watcher : watchers)
+    {
+        if (contains(m_watchers, watcher)) // make sure this watcher is still alive
+            watcher->on_option_changed(option);
+    }
 }
 
 CandidateList OptionsRegistry::complete_option_name(StringView prefix,
diff --git a/test/regression/1227-segfault-on-option-access/cmd b/test/regression/1227-segfault-on-option-access/cmd
new file mode 100644
index 00000000..1340e922
--- /dev/null
+++ b/test/regression/1227-segfault-on-option-access/cmd
@@ -0,0 +1 @@
+:test<ret>
diff --git a/test/regression/1227-segfault-on-option-access/in b/test/regression/1227-segfault-on-option-access/in
new file mode 100644
index 00000000..8b137891
--- /dev/null
+++ b/test/regression/1227-segfault-on-option-access/in
@@ -0,0 +1 @@
+
diff --git a/test/regression/1227-segfault-on-option-access/out b/test/regression/1227-segfault-on-option-access/out
new file mode 100644
index 00000000..b68fde2a
--- /dev/null
+++ b/test/regression/1227-segfault-on-option-access/out
@@ -0,0 +1 @@
+k
diff --git a/test/regression/1227-segfault-on-option-access/rc b/test/regression/1227-segfault-on-option-access/rc
new file mode 100644
index 00000000..35f1dcd8
--- /dev/null
+++ b/test/regression/1227-segfault-on-option-access/rc
@@ -0,0 +1,10 @@
+decl str _
+
+hook global BufCreate \*test\* %{
+    hook buffer BufSetOption _=.+ 'exec "i%opt{_}"'
+}
+
+def test %{
+    edit -scratch *test*
+    set buffer=*test* _ "k"
+}