I cannot reproduce this from my end.

$ spyder3
libpng warning: iCCP: known incorrect sRGB profile
libpng warning: iCCP: known incorrect sRGB profile

$ rpm -qa python3-spyder python3-QtPy
python3-spyder-3.2.8-1.fc28.noarch
python3-QtPy-1.4.0-1.fc28.noarch


Having said that, the issue seems to be this line here - 

def check_qt():
     """Check Qt binding requirements"""
     qt_infos = dict(pyqt5=("PyQt5", "5.2"), pyqt=("PyQt4", "4.6"))
     try:
         import qtpy
         package_name, required_ver = qt_infos[qtpy.API]                     
         actual_ver = qtpy.PYQT_VERSION


Please post output from a python console for the following

import qtpy

qtpy.API

qtpy.PYQT_VERSION


Additionally, do you have pyqt4 packages installed? I wonder if that's got something to do with this error as well.

Note that the dictionary qt_infos lists pyqt instead of pyqt4 ...

Here are the results of the following commands:

>>> import qtpy
>>> qtpy.API
'pyqt5'
>>> qtpy.PYQT_VERSION
'5.9.1'

Indeed both PyQt4 and PyQt5 are installed....
Doing sudo dnf remove python3-PyQt4 fixed the problem.

Thank for your help !

However someone could need python3-PyQt4, so a blanket removal is a little too much. 

I assumed the issue was in python3-QtPy since comparing the list of installed packages of 2 workstations (one where spyder3 was working and one where did not) and updating the packages one by one in the good workstation, it was python3-QtPy that once updated broke spyder3.

If it comes from somewhere else, I have no idea.

(In reply to Raimondo Giammanco from comment #3)
> However someone could need python3-PyQt4, so a blanket removal is a little
> too much. 

That's precisely why I have not closed the issue yet.

> 
> I assumed the issue was in python3-QtPy since comparing the list of
> installed packages of 2 workstations (one where spyder3 was working and one
> where did not) and updating the packages one by one in the good workstation,
> it was python3-QtPy that once updated broke spyder3.
> 
> If it comes from somewhere else, I have no idea.


Can you please post the output for the commands I have listed in comment #1 from both machines?

Taking two other workstations in a similar configuration (i.e. one full up to date where spyder3 is not working and one a little behind in updates where spyder3 is working):

OLD (spyder3 works):
Python 3.6.4 (default, Mar 13 2018, 18:18:20) 
[GCC 7.3.1 20180303 (Red Hat 7.3.1-5)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import qtpy
>>> qtpy.API
'pyqt5'
>>> qtpy.PYQT_VERSION
'5.9.1'
>>> 

NEW (spyder3 does not work):
Python 3.6.5 (default, Apr  4 2018, 15:01:18) 
[GCC 7.3.1 20180303 (Red Hat 7.3.1-5)] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import qtpy
>>> qtpy.API
'pyqt5'
>>> qtpy.PYQT_VERSION
'5.9.1'
>>> 

Will add a file with the diff of the installed packages.

Created attachment 1424043 [details]
diff between rpm list between 2 machines (old-new)

Hmmm ... I can reproduce this in the following scenarios but ONLY when I have python3-PyQt4 installed.


spyder-3.2.8 + python-qtpy-1.4.0

spyder-3.2.8 + python-qtpy-1.3.1

spyder-3.2.7 + python-qtpy-1.4.0

spyder-3.2.7 + python-qtpy-1.3.1


So ... pretty much every configuration. I will have to dig more. :(

The strange thing here is that even with pyqt4 installed, I can launch spyder3 from an ipython shell - like this.

$ ipython3 
Python 3.6.5 (default, Apr  4 2018, 15:01:18) 
Type 'copyright', 'credits' or 'license' for more information
IPython 6.2.1 -- An enhanced Interactive Python. Type '?' for help.

In [1]: from spyder.app import mainwindow

In [2]: mainwindow.main()
libpng warning: iCCP: known incorrect sRGB profile
libpng warning: iCCP: known incorrect sRGB profile


This works! But, typing spyder3 on a terminal or from a menu - no dice.

I can reproduce this in all configurations in comment #7.

So, I am positive this has nothing to do with the QtPy update. That said, I am still interested in trying to get this figured out.

Aha! One more question - do you have pandas installed in your system?

Plenty of bamboo eaters: 

python2-pandas-datareader-0.3.0-2.post0.fc27.noarch
python2-pandas-0.20.1-3.fc27.x86_64
python3-pandas-0.20.1-3.fc27.x86_64
python3-pandas-datareader-0.3.0-2.post0.fc27.noarch


Same version on the two workstations mentioned on comments #5 and #6

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