Segfault on QgsMapCanvas() creation

[qgib]

Author Name: D. Hiepler (D. Hiepler)
Original Redmine Issue: 14217
Affected QGIS version: master
Redmine category:python_plugins

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I modified the example code from http://docs.qgis.org/testing/en/docs/pyqgis_developer_cookbook/canvas.html#writing-custom-map-canvas-items
and ended up with

import sys
from qgis.core import QgsApplication, QgsProject
from qgis.gui import QgsMapCanvas

1. install prefix - optional, if QGIS_PREFIX_PATH is set
QgsApplication.setPrefixPath('/usr', True)  
1. where the auth database is - optional, if QGIS_AUTH_DB_DIR_PATH is set 
QgsApplication.setAuthDbDirPath('.')  

1. init application context
app = QgsApplication(sys.argv, False)
app.initQgis()

1. Map canvas
canvas = QgsMapCanvas()    # <- segfault
canvas.show()

app.exec_()

QgsApplication.exitQgis()

But with current master, it crashes (i suppose there's some Qt initialization missing):

Program received signal SIGSEGV, Segmentation fault.
0x00007ffff2e9c88c in QCursor::pos() () from /usr/lib64/qt4/libQtGui.so.4
(gdb) bt
#_0  0x00007ffff2e9c88c in QCursor::pos() () from /usr/lib64/qt4/libQtGui.so.4
#_1  0x00007ffff2e2fd57 in QMouseEvent::QMouseEvent(QEvent::Type, QPoint const&, Qt::MouseButton, QFlags<Qt::MouseButton>, QFlags<Qt::KeyboardModifier>) () from /usr/lib64/qt4/libQtGui.so.4
#_2  0x00007ffff340bbaa in QGraphicsViewPrivate::QGraphicsViewPrivate() () from /usr/lib64/qt4/libQtGui.so.4
#_3  0x00007ffff340bedf in QGraphicsView::QGraphicsView(QWidget*) () from /usr/lib64/qt4/libQtGui.so.4
#_4  0x00007fffe328fa0b in QgsMapCanvas::QgsMapCanvas(QWidget*, char const*) () from /usr/lib64/libqgis_gui.so.2.13.0
#_5  0x00007fffe3c7ce63 in sipQgsMapCanvas::sipQgsMapCanvas(QWidget*, char const*) ()
   from /usr/lib64/python2.7/site-packages/qgis/_gui.so
#_6  0x00007fffe3c8addf in init_type_QgsMapCanvas () from /usr/lib64/python2.7/site-packages/qgis/_gui.so
#_7  0x00007ffff6684733 in sipSimpleWrapper_init () from /usr/lib64/python2.7/site-packages/sip.so
#_8  0x00007ffff7aae8ef in type_call () from /usr/lib64/libpython2.7.so.1.0
#_9  0x00007ffff7a5b533 in PyObject_Call () from /usr/lib64/libpython2.7.so.1.0
#_10 0x00007ffff7aedb8a in PyEval_EvalFrameEx () from /usr/lib64/libpython2.7.so.1.0
#_11 0x00007ffff7af0ac0 in PyEval_EvalCodeEx () from /usr/lib64/libpython2.7.so.1.0
#_12 0x00007ffff7af0bb9 in PyEval_EvalCode () from /usr/lib64/libpython2.7.so.1.0
#_13 0x00007ffff7b0961f in run_mod () from /usr/lib64/libpython2.7.so.1.0
#_14 0x00007ffff7b0a772 in PyRun_FileExFlags () from /usr/lib64/libpython2.7.so.1.0
#_15 0x00007ffff7b0b877 in PyRun_SimpleFileExFlags () from /usr/lib64/libpython2.7.so.1.0
#_16 0x00007ffff7b1c6da in Py_Main () from /usr/lib64/libpython2.7.so.1.0
#_17 0x00007ffff747a7b0 in __libc_start_main () from /lib64/libc.so.6
#_18 0x0000000000400759 in _start ()

[qgib]

Author Name: D. Hiepler (D. Hiepler)

---

PS: I forgot to mention, that I modified the example code to work around #21539

[qgib]

Author Name: Giovanni Manghi (@gioman)

---

• fixed_version_id was configured as Future Release - High Priority
• priority_id was changed from Normal to High

[qgib]

Author Name: Matthias Kuhn (@m-kuhn)

---

Make it a gui application and it will work:

app = QgsApplication(sys.argv, True)

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• resolution was changed from to invalid
• status_id was changed from Open to Closed