gselzer
commented
2 years ago @hinerm suggested I make a MCVE. I determined that the issue lies with the interaction between JPype and magicgui, as JPype.startJVM() is enough to cause the error. I had less luck creating a script MCVE that showed the error. I tried writing the following:
import jpype
import IPython.core.ultratb
jpype.startJVM()
System = jpype.JClass('java.lang.System')
vbtb = IPython.core.ultratb.VerboseTB()
def foo(s):
raise ValueError('foo')
# Get an exception with a stack trace
try:
foo(System)
except ValueError as exc:
e = exc
print(vbtb.text(e.__class__, e, e.__traceback__))
kephale
A peculiar set of circumstances cause segmentation faults when running the plugin.
Callablewith a faulty signature must be passed tomagicgui.This is not specific to napari-imagej; see https://github.com/gselzer/napari-foobar/commit/993f3019298bb744e0c139afde8c5612dae9ad81for a reproducible example. It is, however, going to affect napari-imagej; if anyone has napari-imagej running, and tries to create any widget that is improperly written (likely due to incorrect
param_options), napari will silently crash.Under the hood, napari is calling
VerboseTBto display the error arising from the call tomagicgui.VerboseTBtries to access the locals at each frame in the error traceback, causing a segfault when looking at the_function_guiframe. TheVerboseTBdocs suggest it prints all variables in the stack; if this is actually what happens, then it is probably trying to call data managed by jpype. JPype seems to still be running by the time we reach the segfault.See https://napari.zulipchat.com/#narrow/stream/309872-plugins/topic/Passing.20parameter.20options.20to.20magicgui/near/273885825