Description
mpl 1.5.1/2.0b3/master, Qt5Agg backend, Python 3.5.2, Arch Linux
plt.plot([-1, -2]); plt.show()
and press l while the mouse is over the axes.
Qt5 aborts Python due to the exception propagating out of the slot:
/usr/lib/python3.5/site-packages/matplotlib/axes/_base.py:2270: RuntimeWarning: invalid value encountered in double_scalars
delta = (x1t - x0t) * margin
Traceback (most recent call last):
File "/usr/lib/python3.5/site-packages/matplotlib/backends/backend_qt5.py", line 314, in keyPressEvent
FigureCanvasBase.key_press_event(self, key, guiEvent=event)
File "/usr/lib/python3.5/site-packages/matplotlib/backend_bases.py", line 1842, in key_press_event
self.callbacks.process(s, event)
File "/usr/lib/python3.5/site-packages/matplotlib/cbook.py", line 550, in process
proxy(*args, **kwargs)
File "/usr/lib/python3.5/site-packages/matplotlib/cbook.py", line 417, in __call__
return mtd(*args, **kwargs)
File "/usr/lib/python3.5/site-packages/matplotlib/backend_bases.py", line 2639, in key_press
key_press_handler(event, self.canvas, self.canvas.toolbar)
File "/usr/lib/python3.5/site-packages/matplotlib/backend_bases.py", line 2546, in key_press_handler
ax.set_yscale('log')
File "/usr/lib/python3.5/site-packages/matplotlib/axes/_base.py", line 3146, in set_yscale
self.autoscale_view(scalex=False)
File "/usr/lib/python3.5/site-packages/matplotlib/axes/_base.py", line 2288, in autoscale_view
margins['bottom'], margins['top'], self.set_ybound)
File "/usr/lib/python3.5/site-packages/matplotlib/axes/_base.py", line 2278, in handle_single_axis
x0, x1 = locator.view_limits(x0, x1)
File "/usr/lib/python3.5/site-packages/matplotlib/ticker.py", line 1803, in view_limits
"Data has no positive values, and therefore can not be "
ValueError: Data has no positive values, and therefore can not be log-scaled.
Fatal Python error: Aborted
Not sure what the best approach is but I think we should certainly try to avoid a fatal crash...
While it may be tempting to just wrap key_press_handler in a try... except or disable the abort()ing behavior of PyQt5 by installing a custom excepthook (see http://pyqt.sourceforge.net/Docs/PyQt5/incompatibilities.html section for PyQt5.5), this would hide the fact that the canvas is left in an inconsistent state as the axes internally believe to have switched to log-scale. This can be seen e.g. by using the Qt4Agg backend (where the exception is printed but the program not abort()ed), by typing l and then trying to zoom in (again with the mouse): the canvas becomes completely empty in that case.