Puppet

What in the world did the bugtracker do to my script?! Let’s try that again:

#!/bin/bash
for LOLWUT in {a..z} do

    cat <<- EOF > /tmp/test.pp
    case \$wtf {
            /$LOLWUT/: {
                    notice("The fact[\$wtf] matches the regex /$LOLWUT/")
            }
            default: {
                    notice("The fact[\$wtf] does NOT match the regex /$LOLWUT/")
            }
    }
    notice(\$facility)
    EOF

    puppet apply /tmp/test.pp
done

Where this gets us in trouble is cases like:

case $schrodingers_fact {
    /\w/: {
        notice("fact is set.  hooray!")
    }
    default: {
        notice("fact is not set.  set it")
        $schrodingers_fact = retrieve_fact_via_carrier_pigeon()
    }
}

…because now Puppet seems to think the fact doesn’t need to be set, when it does. This idiom worked swimmingly in Puppet 0.25.x, and seems to have stopped working in the 2.6.x vintage.

A look over the results of the test script shows it matching on the letters D, E, F, N, and U. I’m no expert, but I’m pretty sure those letters spell “undef”.

↑ This is funny.

A workaround from the manifest side, for those of us who get our software from upstream packages and don’t modify it:

case $schrodingers_fact {
    /^undef$/: { notice("do the non-matching stuff here") }
    /\w/:      { notice("do the matching stuff here") }
    default:   { notice("do the non-matching stuff here") }
}

Yes, it’s icky, and it involves repeating repeating yourself. That’s why they call them bugs.

You can also use the empty (literal) string for the non-matching case, if you want; that will actually be safe in the longest term, assuming that “I have an empty string” is also a failure case for your fact. :)