dispatch: move some helper functions down into scmutil I plan to reuse `formatparse()` in the next patch. Differential Revision: https://phab.mercurial-scm.org/D9331

errors: raise more specific errors from rewriteutil Differential Revision: https://phab.mercurial-scm.org/D9330

chgserver: backport py3 buffered I/O workarounds from procutil I've recently switched to new machine and I found chg's stdout is fully buffered. Even though chg server is a daemon process, it inherits the environment where the chg client originally forked the server. This means the server's stdout might have been wrapped by LineBufferedWrapper. That's why we need to do wrap/unwrap in both ways. The "if" condition in _restoreio() looks weird, but I'm not willing to clean things up because stdio behavior is fundamentally different between py2 and py3, and py2 support will be dropped anyway.

chg: reset errno prior to calling strtol() Otherwise we can't figure out if the last strtol() invocation failed or not.

chg: do not close dir fd while iterating It works so long as the dp is the last entry, but readdir(dp) would fail with EBADF. Let's not do that and close the dir fd explicitly.

chg: show debug message for each fd to be closed It helps debugging. The number of file descriptors should be small in most cases, so the console output wouldn't get bloated even with CHG_DEBUG=1.

chg: apply clang-format

errors: use InputError for some errors on `hg clone` Differential Revision: https://phab.mercurial-scm.org/D9329