biber first aid for “data source not found”

TeX, kludgetastic

I don’t know what causes it, but every now and then biber gives up working on my system. Then I start getting error messages like data source /var/folders/m6/bn7r45zx6cx55rr9g4qh6s6w0000gn/T/par-agoldst/cache-87e533530c5239fb9f8e3ff008979f1f16ea0e5e//inc/lib/Biber/LaTeX/recode_data.xml not found in .

There is a magic incantation, which I found somewhere on the biber sourceforge forums, to get biber to clear the cobwebs by reinstalling itself using perl’s PAR tool, as it does the first time it is run on a new system. Just clear the PAR cache, whose location under /var is helpfully specified in the error message:

 sudo rm -rf /var/folders/m6/bn7r45zx6cx55rr9g4qh6s6w0000gn/T/par-agoldst

You will have different stuff in /var/folders.../par-<username>.

Since I’ve seen other people complaining of this, I’m convinced it’s not my fault but the result of some deeply buried sporadic bug in biber. I’d try harder to figure it out, but it’s just too easy to make this one go away when it pops up once every few months. TeX is hacking, people!