ChimeraX tries to open debugger arguments as if they were files

[Zach Pearson]

When started with a debugger (at least on Mac), ChimeraX somehow gets the arguments to the debugger (-Xfrozen_modules=off, the path to debugpy) and attempts to open them as if they were drag-and-dropped files.

[Eric Pettersen]

Word of warning on this one. On the Mac, command line arguments also show up as drop events, so to avoid opening files twice (but still opening legitimate drops correctly) there is some complicated interplay between the command-line argument processing and the handling of drop events (most of the latter of which is in ui.gui.event() and ui.gui.open_pending_files())

[Zach Pearson]

The simplest thing I can think of is to test whether the file actually exists -- frozen_modules=off and chimerax.core will not -- before trying to open the file in those event handlers. That cuts it down to /path/to/ChimeraX.app/Contents/Library/Frameworks/Python.framework/Versions/3.11/lib/python3.11/site-packages/debugpy/launcher/../../debugpy

[Zach Pearson]

This is mostly a bug in the debuggers/DAP implementations, where (in the case of emacs's DAP package) if no arguments are passed in the name of the buffer is given as an argument.

Debugpy does pass itself as an argument to ChimeraX and I've ignored that in gui.py ​here.