#357 Milltask segfault when opening a missing file

[Robert Ellenberg]

Milltask has segfaulted sometimes when opening a file that is missing on disk from the recent file list. Here's how I've seen this happen:

1) Open an axis sim config and load a g code program (such as the one attached). Power up, home, and run the program for a short time.
2) outside of LCNC, move or rename the program
3) Open a different program, then try to open the original program from the recent files list.

This doesn't cause a segfault 100% of the time, but it often causes a crash of some sort.

(This bug was originally reported by Curtis Dutton on the EMC mailing lists)

[Robert Ellenberg]

This may be overlapping with another error in axis as well. At line 1075 in axis.py, this command reads lines from the file:

lines = open(f).readlines()

However, if this throws an IO exception, it doesn't appear to be handled by anything, and axis quits. Is there a way for "open_file_guts" to fail gracefully?

[Sebastian Kuzminsky]

The bug also happens on 2.5.

I just pushed a branch called return-from-o-word that adds a test that reproduces the problem reliably in sim.

[Michael Haberler]

fixed in v2.5_branch:
http://git.linuxcnc.org/gitweb?p=linuxcnc.git;a=commit;h=fcc0e71d04b0dab448b1e8d890b2f72cf2268eec