tar_render_rep() with any number of output reports

[ugoebel73]

Our bioinformatics "targets" pipeline branches over the experimental contrasts of an input study (e.g., "treatmentA vs treatmentB") and is intended to render a separate output report for each contrast. Ideally any number of contrasts should be handled automatically.

tar_render_rep() with default parameters fails if there is only a single contrast. However it does pass if parameter "batches" is set to 2. This can be traced back to the as.integer(cut(seq_len(nrow(params)), breaks = batches)) call in function tarchetypes::tar_render_rep_run_params(): if nrow(params)=1, then this yields NA with batches=1, but 1 with batches=2.

I post this observation here because I am aware that tar_render_rep() is specifically meant for multiple output reports, so this behavior may not necessarily be considered a bug. However if tar_render_rep_run_params() could be made to handle the special case of a single report, this would simplify the handling of cases like ours, where the number of reports is not known in advance.

I have prepared a minimal example and could file a bug report if it is considered appropriate.

[ugoebel73]

Thanks a lot Will, it works fine now!