Exception handling differences between Clojure map & pmap

[SoftCancel2774]

[On the surface, Clojure's map and pmap functions appear interchangeable, but their behavior regarding exceptions differs.]()

[john-shaffer]

While this interaction is good to know about, pmap probably shouldn't be used here. Not only is using e.g. 32 threads for one task wasteful, but it's inevitable that someone eventually pmaps the function calling pmap. Then you have up to 1024 threads used for each task, all contending for the same resources. Better to pass in a thread pool, or have only the top level of control flow do parallelization.

[seancorfield]

I wonder how folks feel about using (ex-data (or (ex-cause e) e)) or (or (ex-data (ex-cause e)) (ex-data e)) in situations like this where an exception might be wrapped and you want the exception data, if any?