logtoprocess: connect all fds to /dev/null to avoid bad interaction with pager We detected that pager is waiting for log-to-process script to finish, which is annoying when adding a script on commandfinish that does an HTTP push. There seems to be no workaround on the script side and it will make the behavior on Linux/MacOS closer to the Windows behavior. The drawback is that it makes the related tests more flaky as log-to-process outputs are now really asynchronous. If it's considered a BC change, another option would be to add a config option for this new behavior. I personally think that the different behavior between Windows and Linux is confusing and that it's a bug I would be fine with a new config option. Differential Revision: https://phab.mercurial-scm.org/D4816