Jupyter Qtconsole can't find PyQt5

[GabrieleZucca]

When launching jupyter qtconsole:

$ jupyter qtconsole
Traceback (most recent call last):
  File "/home/gabriele/.local/bin/jupyter-qtconsole", line 6, in <module>
    from qtconsole.qtconsoleapp import main
  File "/home/gabriele/.local/lib/python3.7/site-packages/qtconsole/qtconsoleapp.py", line 60, in <module>
    from qtconsole.qt import QtCore, QtGui
  File "/home/gabriele/.local/lib/python3.7/site-packages/qtconsole/qt.py", line 23, in <module>
    QtCore, QtGui, QtSvg, QT_API = load_qt(api_opts)
  File "/home/gabriele/.local/lib/python3.7/site-packages/qtconsole/qt_loaders.py", line 387, in load_qt
    api_options))
ImportError: 
    Could not load requested Qt binding. Please ensure that
    PyQt4 >= 4.7, PyQt5, PySide >= 1.0.3 or PySide2 is available,
    and only one is imported per session.

    Currently-imported Qt library:   None
    PyQt4 installed:                 False
    PyQt5 installed:                 False
    PySide >= 1.0.3 installed:       False
    PySide2 installed:               False
    Tried to load:                   ['pyqt5', 'pyside2', 'pyside', 'pyqt']

My system is Xubuntu 19.10 64 bit. Further info:

$ python3 --version
Python 3.7.5

$ pip3 --version
pip 18.1 from /usr/lib/python3/dist-packages/pip (python 3.7)

$ pip3 show jupyter
Name: jupyter
Version: 1.0.0
Summary: Jupyter metapackage. Install all the Jupyter components in one go.
Home-page: http://jupyter.org
Author: Jupyter Development Team
Author-email: jupyter@googlegroups.org
License: BSD
Location: /home/gabriele/.local/lib/python3.7/site-packages
Requires: ipykernel, jupyter-console, qtconsole, nbconvert, ipywidgets, notebook
Required-by: 

$ pip3 show pyqt5
Name: PyQt5
Version: 5.12.3
Summary: None
Home-page: None
Author: None
Author-email: None
License: None
Location: /usr/lib/python3/dist-packages
Requires: 
Required-by: 

Jupyter has been installed with pip3 with the --user option, while PyQt5 has been installed with apt (package: python3-pyqt5).

[wmvanvliet]

What happens if you open a regular python REPL and do: from PyQt5 import QtGui?

[GabrieleZucca]

It loads without any error it seems.

PS: Inoticed that on my other PC jupyter qtconsole works. The main difference is that on that other PC jupyter has been installed system-wide with sudo pip3 install jupyter instead of pip3 install --user jupyter. The OS is the same.

[wmvanvliet]

Can you try with the latest master? I think we recently changed our QT detection code for the better.

[GabrieleZucca]

I tried reinstalling from GitHub with pip3 install --user git+https://github.com/jupyter/qtconsole and now I get a different error:

Traceback (most recent call last):
  File "/home/gabriele/.local/bin/jupyter-qtconsole", line 6, in <module>
    from qtconsole.qtconsoleapp import main
  File "/home/gabriele/.local/lib/python3.7/site-packages/qtconsole/qtconsoleapp.py", line 65, in <module>
    from qtconsole.rich_jupyter_widget import RichJupyterWidget
  File "/home/gabriele/.local/lib/python3.7/site-packages/qtconsole/rich_jupyter_widget.py", line 13, in <module>
    from qtconsole.svg import save_svg, svg_to_clipboard, svg_to_image
  File "/home/gabriele/.local/lib/python3.7/site-packages/qtconsole/svg.py", line 5, in <module>
    from qtpy import QtCore, QtGui, QtSvg, QtWidgets
  File "/home/gabriele/.local/lib/python3.7/site-packages/qtpy/QtSvg.py", line 14, in <module>
    from PyQt5.QtSvg import *
ModuleNotFoundError: No module named 'PyQt5.QtSvg'

I cannot load it in a normal python3 repl either.

[GabrieleZucca]

After the last post I installed the python3-pyqt5.qtsvg package with apt and now the qtconsole seems to work, even if the terminal shows some errors:

Traceback (most recent call last):
  File "/home/gabriele/.local/lib/python3.7/site-packages/qtconsole/base_frontend_mixin.py", line 138, in _dispatch
    handler(msg)
  File "/home/gabriele/.local/lib/python3.7/site-packages/qtconsole/frontend_widget.py", line 504, in _handle_inspect_reply
    self._call_tip_widget.show_inspect_data(content)
  File "/home/gabriele/.local/lib/python3.7/site-packages/qtconsole/call_tip_widget.py", line 134, in show_inspect_data
    return self.show_tip(self._format_tooltip(text))
  File "/home/gabriele/.local/lib/python3.7/site-packages/qtconsole/call_tip_widget.py", line 158, in show_tip
    screen_rect = QtWidgets.QApp.desktop().screenGeometry(text_edit)
AttributeError: module 'qtpy.QtWidgets' has no attribute 'QApp'

EDIT: Replacing the 2 occurrencies of QApp with qApp in qtconsole/call_tip_widget.py solves the problem :)

[wmvanvliet]

Great that you solved it. Seems like a compatibility PR is called for, based on your observations.