NSIS: Remove installation dir if it exists

If we don't do this, when a newer version is installed on top of an older one,
old files which have been deleted persist. In the case of v1.3.3 -> v1.4.0,
this means qutebrowser won't start because of a leftover sip installation which
confuses PyQt 5.11.

This is still potentially dangerous as the user could use e.g. C:\ as
installation path, but we have that issue when uninstalling anyways.
See http://nsis.sourceforge.net/Uninstall_only_installed_files

.github/CONTRIBUTING.asciidoc

@@ -1,3 +1,8 @@
+IMPORTANT: I'm currently (July 2018) more busy than usual until September,
+because of exams coming up. Review of non-trivial pull requests will thus be
+delayed until then. If you're reading this note after mid-September, please
+open an issue.
+
 - Before you start to work on something, please leave a comment on the relevant
   issue (or open one). This makes sure there is no duplicate work done.
 

doc/changelog.asciidoc

@@ -15,6 +15,14 @@ breaking changes (such as renamed commands) can happen in minor releases.
 // `Fixed` for any bug fixes.
 // `Security` to invite users to upgrade in case of vulnerabilities.
 
+v1.5.0 (unreleased)
+-------------------
+
+Fixed
+~~~~~
+
+- Rare crash when an error occurs in downloads.
+
 v1.4.0
 ------
 

doc/contributing.asciidoc

@@ -5,6 +5,11 @@ The Compiler <mail@qutebrowser.org>
 :data-uri:
 :toc:
 
+IMPORTANT: I'm currently (July 2018) more busy than usual until September,
+because of exams coming up. Review of non-trivial pull requests will thus be
+delayed until then. If you're reading this note after mid-September, please
+open an issue.
+
 I `&lt;3` footnote:[Of course, that says `<3` in HTML.] contributors!
 
 This document contains guidelines for contributing to qutebrowser, as well as

doc/install.asciidoc

@@ -392,6 +392,10 @@ https://docs.python.org/3/library/venv.html[virtual environment]:
 $ tox -e mkvenv-pypi
 ----
 
+If your system comes with Python 3.5.3 or older (such as Ubuntu 16.04 LTS), use
+`tox -e mkvenv-pypi-old` instead. This installs an older Qt version (5.10) due
+to bugs in newer versions.
+
 This installs all needed Python dependencies in a `.venv` subfolder.
 
 This comes with an up-to-date Qt/PyQt including QtWebEngine, but has a few

misc/qutebrowser.nsi

@@ -40,6 +40,8 @@ Section "Install"
   ; Uninstall old versions
   ExecWait 'MsiExec.exe /quiet /qn /norestart /X{633F41F9-FE9B-42D1-9CC4-718CBD01EE11}'
   ExecWait 'MsiExec.exe /quiet /qn /norestart /X{9331D947-AC86-4542-A755-A833429C6E69}'
+  RMDir /r "$INSTDIR\*.*"
+  CreateDirectory "$INSTDIR"
 
   SetOutPath "$INSTDIR"
   

qutebrowser/browser/qtnetworkdownloads.py

@@ -29,7 +29,7 @@ from PyQt5.QtCore import pyqtSlot, pyqtSignal, QTimer
 from PyQt5.QtNetwork import QNetworkRequest, QNetworkReply
 
 from qutebrowser.config import config
-from qutebrowser.utils import message, usertypes, log, urlutils, utils
+from qutebrowser.utils import message, usertypes, log, urlutils, utils, debug
 from qutebrowser.browser import downloads
 from qutebrowser.browser.webkit import http
 from qutebrowser.browser.webkit.network import networkmanager
@@ -307,7 +307,14 @@ class DownloadItem(downloads.AbstractDownloadItem):
         """Handle QNetworkReply errors."""
         if code == QNetworkReply.OperationCanceledError:
             return
-        self._die(self._reply.errorString())
+
+        if self._reply is None:
+            error = "Unknown error: {}".format(
+                debug.qenum_key(QNetworkReply, code))
+        else:
+            error = self._reply.errorString()
+
+        self._die(error)
 
     @pyqtSlot()
     def _on_read_timer_timeout(self):

qutebrowser/browser/webengine/webenginequtescheme.py

@@ -37,6 +37,7 @@ class QuteSchemeHandler(QWebEngineUrlSchemeHandler):
         if qtutils.version_check('5.11', compiled=False):
             # WORKAROUND for https://bugreports.qt.io/browse/QTBUG-63378
             profile.installUrlSchemeHandler(b'chrome-error', self)
+            profile.installUrlSchemeHandler(b'chrome-extension', self)
 
     def requestStarted(self, job):
         """Handle a request for a qute: scheme.
@@ -49,7 +50,7 @@ class QuteSchemeHandler(QWebEngineUrlSchemeHandler):
         """
         url = job.requestUrl()
 
-        if url.scheme() == 'chrome-error':
+        if url.scheme() in ['chrome-error', 'chrome-extension']:
             # WORKAROUND for https://bugreports.qt.io/browse/QTBUG-63378
             job.fail(QWebEngineUrlRequestJob.UrlInvalid)
             return

qutebrowser/utils/version.py

@@ -484,6 +484,7 @@ def pastebin_version(pbclient=None):
 
     def _on_paste_version_success(url):
         global pastebin_url
+        url = url.strip()
         _yank_url(url)
         pbclient.deleteLater()
         pastebin_url = url

tests/unit/utils/test_version.py

@@ -987,11 +987,12 @@ def test_pastebin_version(pbclient, message_mock, monkeypatch, qtbot):
     monkeypatch.setattr('qutebrowser.utils.utils.log_clipboard', True)
 
     version.pastebin_version(pbclient)
-    pbclient.success.emit("test")
+    pbclient.success.emit("https://www.example.com/\n")
 
     msg = message_mock.getmsg(usertypes.MessageLevel.info)
-    assert msg.text == "Version url test yanked to clipboard."
-    assert version.pastebin_url == "test"
+    expected_text = "Version url https://www.example.com/ yanked to clipboard."
+    assert msg.text == expected_text
+    assert version.pastebin_url == "https://www.example.com/"
 
 
 def test_pastebin_version_twice(pbclient, monkeypatch):
@@ -1000,16 +1001,16 @@ def test_pastebin_version_twice(pbclient, monkeypatch):
                         lambda: "dummy")
 
     version.pastebin_version(pbclient)
-    pbclient.success.emit("test")
+    pbclient.success.emit("https://www.example.com/\n")
 
     pbclient.url = None
     pbclient.data = None
-    version.pastebin_url = "test2"
+    version.pastebin_url = "https://www.example.org/"
 
     version.pastebin_version(pbclient)
     assert pbclient.url is None
     assert pbclient.data is None
-    assert version.pastebin_url == "test2"
+    assert version.pastebin_url == "https://www.example.org/"
 
 
 def test_pastebin_version_error(pbclient, caplog, message_mock, monkeypatch):

tox.ini

@@ -62,6 +62,19 @@ deps =
     -r{toxinidir}/requirements.txt
     -r{toxinidir}/misc/requirements/requirements-pyqt.txt
 
+# Older PyQt for Python 3.5
+# 5.11.2: https://www.riverbankcomputing.com/pipermail/pyqt/2018-July/040511.html
+# 5.10.1: https://github.com/qutebrowser/qutebrowser/issues/3662
+[testenv:mkvenv-pypi-old]
+basepython = {env:PYTHON:python3.5}
+envdir = {toxinidir}/.venv
+commands = {envpython} -c ""
+usedevelop = true
+deps =
+    -r{toxinidir}/requirements.txt
+    PyQt5==5.10
+    sip==4.19.8
+
 [testenv:misc]
 ignore_errors = true
 basepython = {env:PYTHON:python3}