From 29ce0a51578df1fa6d0aa08c7128d0bec1d51255 Mon Sep 17 00:00:00 2001
From: Florian Bruhin <git@the-compiler.org>
Date: Thu, 18 Dec 2014 23:04:43 +0100
Subject: [PATCH] Fix handling of small/big fuzzyval's in NeighborList.

This fixes an exception when having a really big or small zoom (e.g. 0) and
then using +/-.

Fixes #361.
---
 .../test/utils/usertypes/test_neighborlist.py | 24 +++++++++++++++++++
 qutebrowser/utils/usertypes.py                | 10 ++++++--
 2 files changed, 32 insertions(+), 2 deletions(-)

diff --git a/qutebrowser/test/utils/usertypes/test_neighborlist.py b/qutebrowser/test/utils/usertypes/test_neighborlist.py
index d74b765bf..51a9d5889 100644
--- a/qutebrowser/test/utils/usertypes/test_neighborlist.py
+++ b/qutebrowser/test/utils/usertypes/test_neighborlist.py
@@ -355,6 +355,30 @@ class SnapInTests(unittest.TestCase):
         self.assertEqual(self.nl.previtem(), 1)
         self.assertEqual(self.nl._idx, 2)
 
+    def test_too_big_next(self):
+        """Test fuzzyval/next with a value bigger than any in the list."""
+        self.nl.fuzzyval = 30
+        self.assertEqual(self.nl.nextitem(), 20)
+        self.assertEqual(self.nl._idx, 0)
+
+    def test_too_big_prev(self):
+        """Test fuzzyval/prev with a value bigger than any in the list."""
+        self.nl.fuzzyval = 30
+        self.assertEqual(self.nl.previtem(), 20)
+        self.assertEqual(self.nl._idx, 0)
+
+    def test_too_small_next(self):
+        """Test fuzzyval/next with a value smaller than any in the list."""
+        self.nl.fuzzyval = 0
+        self.assertEqual(self.nl.nextitem(), 1)
+        self.assertEqual(self.nl._idx, 2)
+
+    def test_too_small_prev(self):
+        """Test fuzzyval/prev with a value smaller than any in the list."""
+        self.nl.fuzzyval = 0
+        self.assertEqual(self.nl.previtem(), 1)
+        self.assertEqual(self.nl._idx, 2)
+
 
 if __name__ == '__main__':
     unittest.main()
diff --git a/qutebrowser/utils/usertypes.py b/qutebrowser/utils/usertypes.py
index c21b7febf..a802e7244 100644
--- a/qutebrowser/utils/usertypes.py
+++ b/qutebrowser/utils/usertypes.py
@@ -116,8 +116,14 @@ class NeighborList(collections.abc.Sequence):
         op = operator.le if offset < 0 else operator.ge
         items = [(idx, e) for (idx, e) in enumerate(self._items)
                  if op(e, self.fuzzyval)]
-        close_item = min(items, key=lambda tpl: abs(self.fuzzyval - tpl[1]))
-        self._idx = close_item[0]
+        if items:
+            item = min(items, key=lambda tpl: abs(self.fuzzyval - tpl[1]))
+        else:
+            sorted_items = sorted([(idx, e) for (idx, e) in
+                                   enumerate(self.items)])
+            idx = 0 if offset < 0 else -1
+            item = sorted_items[idx]
+        self._idx = item[0]
         return self.fuzzyval not in self._items
 
     def _get_new_item(self, offset):