po_extract fails with 'if (target_arg == 0L) { : the condition has length > 1'

[MichaelChirico]

From running on {data.table} at Rdatatable/data.table@f6dca2d

potools::po_extract(
  custom_translation_functions = list(
    R = 'catf:fmt|1',
    src = c('STOP:1', 'DTWARN:1', 'DTPRINT:1', 'snprintf:3')
  )
)

I may be just forgetting how po_extract() works, or may have mis-specified the src custom specification, but this error is not the correct way to surface the issue.

[MichaelChirico]

Debugging a little bit, removing snprintf:3 allowed the extraction to succeed.