Package: libqt5core5a
Version: 5.11.2+dfsg-4
Severity: important
Tags: patch upstream
Hello,
A long-standing bug affects the PyQt5 (and previously the PyQt4)
packages, whereby they crash on Debian-based systems which have the
NVIDIA libraries installed. The following almost minimal code
crashes:
#!/usr/bin/python3
import sys
from PyQt5.QtCore import QUrl
from PyQt5.QtWidgets import QApplication
from PyQt5.QtWebEngineWidgets import QWebEngineView
app = QApplication(sys.argv)
wv = QWebEngineView()
wv.load(QUrl('about:blank'))
wv.show()
app.exec_()
See for example:
https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=912925
https://bugs.launchpad.net/ubuntu/+source/python-qt4/+bug/941826
I have managed to track down the source of the error and reported it
upstream (along with debugging logs and so on) at:
https://bugreports.qt.io/browse/QTBUG-71488
It turns out that the bug lies in the libqt5core5a library, which
tries loading libGL.so before trying libGL.so.1, which is the wrong
order (in particular on Debian-based systems - see the above Debian
bug report for a discussion of why). I have created and tested the
attached patch for the bug.
It would be great if this patch could be applied to Debian before
buster is frozen; it probably won't make it into the upstream sources
in time for buster (because it would presumably go into the 5.12.x
tree).
Thanks!
Julian
-- System Information:
Debian Release: buster/sid
APT prefers stretch
APT policy: (500, 'stretch'), (500, 'testing'), (500, 'stable')
Architecture: amd64 (x86_64)
Foreign Architectures: i386
Kernel: Linux 4.14.0-3-amd64 (SMP w/4 CPU cores)
Locale: LANG=en_GB.utf8, LC_CTYPE=en_GB.utf8 (charmap=UTF-8) (ignored: LC_ALL
set to en_GB.UTF-8), LANGUAGE=en_GB.utf8 (charmap=UTF-8) (ignored: LC_ALL set
to en_GB.UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)
LSM: AppArmor: enabled
Versions of packages libqt5core5a depends on:
ii libc6 2.27-8
ii libdouble-conversion1 3.1.0-2
ii libgcc11:8.2.0-9
ii libglib2.0-0 2.58.1-2
ii libicu60 60.2-6
ii libpcre2-16-0 10.32-3
ii libstdc++6 8.2.0-9
ii zlib1g 1:1.2.11.dfsg-1
Versions of packages libqt5core5a recommends:
ii qttranslations5-l10n 5.11.2-2
Versions of packages libqt5core5a suggests:
ii libthai0 0.1.28-1
-- no debconf information
--- a/src/plugins/platforms/xcb/gl_integrations/xcb_glx/qglxintegration.cpp
+++ b/src/plugins/platforms/xcb/gl_integrations/xcb_glx/qglxintegration.cpp
@@ -650,9 +650,9 @@
#if QT_CONFIG(library)
extern const QString qt_gl_library_name();
//QLibrary lib(qt_gl_library_name());
-QLibrary lib(QLatin1String("GL"));
+QLibrary lib(QLatin1String("GL"), 1);
if (!lib.load())
-lib.setFileNameAndVersion(QLatin1String("GL"), 1);
+lib.setFileName(QLatin1String("GL"));
glXGetProcAddressARB = (qt_glXGetProcAddressARB)
lib.resolve("glXGetProcAddressARB");
#endif
}
