network.qutescheme: Workaround for segfault on exceptions.

qutebrowser/network/qutescheme.py

@@ -27,6 +27,8 @@ Module attributes:
     pyeval_output: The output of the last :pyeval command.
 """
 
+import traceback
+
 from PyQt5.QtNetwork import QNetworkReply
 
 import qutebrowser
@@ -53,22 +55,36 @@ class QuteSchemeHandler(schemehandler.SchemeHandler):
         Return:
             A QNetworkReply.
         """
-        path = request.url().path()
-        # An url like "qute:foo" is split as "scheme:path", not "scheme:host".
-        logutils.misc.debug("url: {}, path: {}".format(
-            request.url().toDisplayString(), path))
         try:
-            handler = getattr(QuteHandlers, path)
-        except AttributeError:
-            errorstr = "No handler found for {}!".format(
-                request.url().toDisplayString())
-            return schemehandler.ErrorNetworkReply(
-                request, errorstr, QNetworkReply.ContentNotFoundError,
-                self.parent())
-        else:
-            data = handler()
-        return schemehandler.SpecialNetworkReply(
-            request, data, 'text/html', self.parent())
+            path = request.url().path()
+            # An url like "qute:foo" is split as "scheme:path", not
+            # "scheme:host".
+            logutils.misc.debug("url: {}, path: {}".format(
+                request.url().toDisplayString(), path))
+            try:
+                handler = getattr(QuteHandlers, path)
+            except AttributeError:
+                errorstr = "No handler found for {}!".format(
+                    request.url().toDisplayString())
+                return schemehandler.ErrorNetworkReply(
+                    request, errorstr, QNetworkReply.ContentNotFoundError,
+                    self.parent())
+            else:
+                data = handler()
+            return schemehandler.SpecialNetworkReply(
+                request, data, 'text/html', self.parent())
+        except BaseException as e:
+            # WORKAROUND
+            # Any exception raised in here will trigger a segfault.
+            # To prevent this, we return a page with the exception info.
+            # FIXME: We should report this to PyQt upstream.
+            text = "Exception in QuteSchemeHandler.createRequest:\n\n"
+            text += traceback.format_exc()
+            text += ("\nPlease use :report to report a bug and add the "
+                     "information printed here by hand.")
+            data = text.encode('utf-8')
+            return schemehandler.SpecialNetworkReply(
+                request, data, 'text/plain', self.parent())
 
 
 class QuteHandlers: