delta-find: split the "sparse" part of `_pre_filter_rev` in a method
Since `_pre_filter_rev` contains logic from various sources of constraint, we
start splitting is in subfunction to clarify and document the grouping.
def run(): from . import demandimport with demandimport.tracing.log('hg script'): demandimport.enable() from . import dispatch dispatch.run()if __name__ == '__main__': run()