mmap: backed out changeset 875d2af8cb4e There have been concrete and theoretical issues raised, this will need more work during the next cycle.

mmap: backed out changeset 74a9f428227e There have been concrete and theoretical issues raised, this will need more work during the next cycle.

help: document the minimumhgversion variable for extensions

help: modernize the example for command registration

Added signature for changeset 593718ff5844

Added tag 4.9rc0 for changeset 593718ff5844

merge default into stable for 4.9 release

update: fix edge-case with update.atomic-file and read-only files We used to create the tempfile with the original file mode. That means creating a read-only tempfile when the original file is read-only, which crash if we need to write on the tempfile. The file in the working directory ends up being writable with and without the atomic update config, so the behavior is the same.

scmutil: drop unreachable except clause socket.error is a subclass of IOError, which we catch higher up. It seems to have been this way since 020a896a5292 (dispatch: sort exception handlers, 2009-01-12), so let's celebrate the 10 year anniversary (a few days late) of it being wrong by deleting it. Differential Revision: https://phab.mercurial-scm.org/D5626

tests: suppress "Checked out 1 paths of <hash>" from modern git test-convert-git.t is failiing since git commit 0f086e6dca (checkout: print something when checking out paths, 2018-11-13). Suppress the new output by disambiguating the arguments with a "--" separator. Differential Revision: https://phab.mercurial-scm.org/D5625