BacktraceFilter returns nil

[lzap]

Hey, I am digging in the codebase but I am unable to find why we see exception "NoMethodError: undefined method `split' for nil:NilClass" on this line:

assert_equal nil, nil

There appear to be somehow complex filtering of stacktrace, but it looks like it returns nil for the object on split is called in our environment:

        where = Minitest.filter_backtrace(caller).first
        where = where.split(/:in /, 2).first # clean up noise

The test in question is: https://ci.theforeman.org/job/test_plugin_matrix/1742/database=postgresql,ruby=2.5,slave=fast/console

I am going to fix our test to avoid those nil values, it was a copy and paste error. But creating this ticket in case you can spot what's actually wrong.

[deivid-rodriguez]

In case it helps, I found this when running mobile-fu tests to package the library for debian, and figured it was an incompatibility with Rails backtrace cleaner. I workarounded it like this, since the BACKTRACE variable is used internally by Rails to avoid backtrace cleaning.

[zenspider]

If this is a test in rails, then it's probably not my backtrace_filter. If so, please file with rails.

[lzap]

I am not sure I understand the problem and I would be able to articulate in RoR. Thanks for help!

[zenspider]

I got a fix into rails AND added some defensive coding to minitest to prevent this in the future. Just released too!