ID 593355 - [3D Arch] Uncaught Exception if there is a permissions issue accessing .FnUsdShim

Problem summary

There is an unhandled exception raised here when encountering a permissions issue with accessing .nuke/.FnUsdShim.
Nuke seems to try reading .FnUsdShim on startup as this might contain the search path for the FnUsdShim plugin that Nuke needs. Nuke tries to first check if this file exists and can be accessed and, if it can't be accessed, Nuke should fallback to default search locations.

Customer reported version
Nuke 15.1v3

Customer reported platform
macOS 13

Steps to reproduce

1) Set your HOME environment variable to a location without permissions to access. (e.g. On my linux machine I did: export HOME=/etc/audit (I also had success with chmod -rwx {my_test_folder}) )

2) Launch Nuke.

Expected behaviour
Nuke should not error when it can't read .fnUsdShim but should fallback to default search locations.

Actual behaviour
Nuke fails to start with a permission issue accessing .fnUsdShim

Workaround
Set your HOME environment variable to a location that Nuke can access.

Reproduced by support
This issue has been identified by our development team.