Fix objreg.first/last_opened_window w/o windows

Before 4cd255c7372625b4c3a630844ffd2b42d6ddde58, we correctly raised
`NoWindow()` via `_window_by_index(-1)`.

After this change, `first_opened_window` and `last_opened_window()`
didn't do anything at all, because their for-loop iterated over an empty
range, thus causing the `Unreachable` to be hit.

This caused #1246 to manifest in a different way than usual. Now, we're
back to the old (still buggy) behavior in that case.

Closes #5849

(cherry picked from commit 18750a332a5474fe42bcdefcf14cea10eec41243)

1 files changed, 4 insertions, 0 deletions

diff --git a/qutebrowser/utils/objreg.py b/qutebrowser/utils/objreg.py
index 587b59629..344b3d660 100644
--- a/qutebrowser/utils/objreg.py
+++ b/qutebrowser/utils/objreg.py
@@ -350,6 +350,8 @@ def _window_by_index(idx: int) -> 'mainwindow.MainWindow':
 
 def last_opened_window() -> 'mainwindow.MainWindow':
     """Get the last opened window object."""
+    if not window_registry:
+        raise NoWindow()
     for idx in range(-1, -(len(window_registry)+1), -1):
         window = _window_by_index(idx)
         if not window.tabbed_browser.is_shutting_down:
@@ -359,6 +361,8 @@ def last_opened_window() -> 'mainwindow.MainWindow':
 
 def first_opened_window() -> 'mainwindow.MainWindow':
     """Get the first opened window object."""
+    if not window_registry:
+        raise NoWindow()
     for idx in range(0, len(window_registry)+1):
         window = _window_by_index(idx)
         if not window.tabbed_browser.is_shutting_down: