From a4d15b550e9669c0b900dead0d21779502b190d1 Mon Sep 17 00:00:00 2001
From: Florian Bruhin <git@the-compiler.org>
Date: Mon, 16 Nov 2015 19:03:07 +0100
Subject: [PATCH] Abort :back/:forward at beginning/end of history.

---
 qutebrowser/browser/commands.py                | 15 +++++++++++----
 tests/integration/features/backforward.feature | 13 +++++++++++++
 2 files changed, 24 insertions(+), 4 deletions(-)

diff --git a/qutebrowser/browser/commands.py b/qutebrowser/browser/commands.py
index 27cc9bc81..15c8168b3 100644
--- a/qutebrowser/browser/commands.py
+++ b/qutebrowser/browser/commands.py
@@ -413,20 +413,27 @@ class CommandDispatcher:
 
     def _back_forward(self, tab, bg, window, count, forward):
         """Helper function for :back/:forward."""
-        if (not forward and not
-                self._current_widget().page().history().canGoBack()):
+        # Catch common cases before e.g. cloning tab
+        history = self._current_widget().page().history()
+        if not forward and not history.canGoBack():
             raise cmdexc.CommandError("At beginning of history.")
-        if (forward and not
-                self._current_widget().page().history().canGoForward()):
+        elif forward and not history.canGoForward():
             raise cmdexc.CommandError("At end of history.")
+
         if tab or bg or window:
             widget = self.tab_clone(bg, window)
         else:
             widget = self._current_widget()
+
+        history = widget.page().history()
         for _ in range(count):
             if forward:
+                if not history.canGoForward():
+                    raise cmdexc.CommandError("At end of history.")
                 widget.forward()
             else:
+                if not history.canGoBack():
+                    raise cmdexc.CommandError("At beginning of history.")
                 widget.back()
 
     @cmdutils.register(instance='command-dispatcher', scope='window',
diff --git a/tests/integration/features/backforward.feature b/tests/integration/features/backforward.feature
index 2ee0486b3..f34d84f3a 100644
--- a/tests/integration/features/backforward.feature
+++ b/tests/integration/features/backforward.feature
@@ -43,6 +43,19 @@ Feature: Going back and forward.
                   url: http://localhost:*/data/backforward/1.txt
                 - url: http://localhost:*/data/backforward/2.txt
 
+    Scenario: Going back in a new tab without history
+        Given I open data/backforward/1.txt
+        When I run :tab-only
+        And I run :back -t
+        Then the error "At beginning of history." should be shown.
+        Then the session should look like:
+            windows:
+            - tabs:
+              - active: true
+                history:
+                - active: true
+                  url: http://localhost:*/data/backforward/1.txt
+
     Scenario: Going back in a new background tab
         Given I open data/backforward/1.txt
         When I open data/backforward/2.txt