graphmod: restore generator nature of dagwalker 9966c95b8c4f introduced the ability to walk the DAG given arbitrary revisions, but changed the behaviour of it to return a list of all nodes (and create a changectx for each one) rather than doing it lazily. This has a pretty significant impact on performance for large repositories (tested on CPython repo, with output disabled): $ time hg glog real 0m2.642s user 0m2.560s sys 0m0.080s Before 9966c95b8c4f: $ time hg glog real 0m0.143s user 0m0.112s sys 0m0.032s And after this fix: $ time hg glog real 0m0.213s user 0m0.184s sys 0m0.028s