Improve serialization crash check

It now works correctly with view-source URLs and is disabled on Qt 5.9.

Fixes #2289
See #2458

CHANGELOG.asciidoc

@@ -68,6 +68,7 @@ Fixed
 - Crash when unbinding an unbound key in the key config
 - Crash when using `:debug-log-filter` when `--filter` wasn't given on startup.
 - Crash with some invalid setting values
+- Crash when cloning a view-source tab with QtWebEngine
 - Various rare crashes
 - Various styling issues with the tabbar and a crash with qt5ct
 

qutebrowser/browser/webengine/webenginetab.py

@@ -379,13 +379,12 @@ class WebEngineHistory(browsertab.AbstractHistory):
 
     def serialize(self):
         if not qtutils.version_check('5.9'):
-            # WORKAROUND for https://bugreports.qt.io/browse/QTBUG-59599
-            if self._history.count() == 0:
-                raise browsertab.WebTabError("Can't serialize page without "
-                                            "history!")
             # WORKAROUND for
             # https://github.com/qutebrowser/qutebrowser/issues/2289
-            scheme = self._history.currentItem().url().scheme()
+            # Don't use the history's currentItem here, because of
+            # https://bugreports.qt.io/browse/QTBUG-59599 and because it doesn't
+            # contain view-source.
+            scheme = self._tab.url().scheme()
             if scheme in ['view-source', 'chrome']:
                 raise browsertab.WebTabError("Can't serialize special URL!")
         return qtutils.serialize(self._history)

tests/end2end/features/conftest.py

@@ -174,13 +174,15 @@ def pdfjs_available():
 
 
 @bdd.when(bdd.parsers.parse("I open {path}"))
-def open_path(quteproc, path):
+def open_path(quteproc, httpbin, path):
     """Open a URL.
 
     If used like "When I open ... in a new tab", the URL is opened in a new
     tab. With "... in a new window", it's opened in a new window. With
     "... as a URL", it's opened according to new-instance-open-target.
     """
+    path = path.replace('(port)', str(httpbin.port))
+
     new_tab = False
     new_bg_tab = False
     new_window = False

tests/end2end/features/tabs.feature

@@ -607,12 +607,19 @@ Feature: Tab management
                   title: Test title
 
     # https://github.com/qutebrowser/qutebrowser/issues/2289
+
     @qtwebkit_skip @qt==5.8.0
     Scenario: Cloning a tab with a special URL
         When I open chrome://gpu
         And I run :tab-clone
         Then the error "Can't serialize special URL!" should be shown
 
+    @qtwebkit_skip @qt<5.9
+    Scenario: Cloning a tab with a view-source URL
+        When I open view-source:http://localhost:(port)
+        And I run :tab-clone
+        Then the error "Can't serialize special URL!" should be shown
+
     @qtwebkit_skip @qt>=5.9
     Scenario: Cloning a tab with a special URL (Qt 5.9)
         When I open chrome://gpu
@@ -774,18 +781,6 @@ Feature: Tab management
             - data/numbers/2.txt
             - data/numbers/3.txt
 
-    # https://github.com/qutebrowser/qutebrowser/issues/2289
-    @qtwebkit_skip @qt>=5.8
-    Scenario: Undoing a tab with a special URL
-        Given I have a fresh instance
-        When I open data/numbers/1.txt
-        And I open chrome://gpu in a new tab
-        And I run :tab-close
-        And I run :undo
-        Then the error "Nothing to undo!" should be shown
-        And the following tabs should be open:
-            - data/numbers/1.txt (active)
-
     # last-close
 
     # FIXME:qtwebengine

tests/end2end/fixtures/quteprocess.py

@@ -314,7 +314,7 @@ class QuteProc(testprocess.Process):
         URLs like about:... and qute:... are handled specially and returned
         verbatim.
         """
-        special_schemes = ['about:', 'qute:', 'chrome:']
+        special_schemes = ['about:', 'qute:', 'chrome:', 'view-source:']
         if any(path.startswith(scheme) for scheme in special_schemes):
             return path
         else: