Does anyone know off the top of their heads if there's a limit to the length of a submit description macro, and if so, what it is?
There's no design limit. There's a good change that things will go sideways at 2 or 4 gigabytes when trying to put the resulting ClassAd attribute on the wire.
I do see the "general remark" in condor_submit's man page that command line arguments must be less than 4k long, but no specifics about length limits for lines within the description, or included lines.
I believe that 4K limit comes more from OS limitations than from HTCondor.
- ToddM