phases: introduce phasecache The original motivation was changectx.phase() had special logic to correctly lookup in repo._phaserev, including invalidating it when necessary. And at other places, repo._phaserev was accessed directly. This led to the discovery that phases state including _phaseroots, _phaserev and _dirtyphase was manipulated in localrepository.py, phases.py, repair.py, etc. phasecache helps encapsulating that. This patch replaces all phase state in localrepo with phasecache and adjust related code except for advance/retractboundary() in phases. These still access to phasecache internals directly. This will be addressed in a followup.

mq: introduce mq.check setting When: [mq] check = True is set, qpush, qpop and qgoto behave as if -c/--check were passed. If incompatible options like -f/--force or --exact are set, this setting is ignored. This setting enables what many users expect mq default behaviour to be.

mq: introduce qgoto --check

mq: introduce qpush --check qpush --check let you qpush with uncommitted files not overlapping patched files.

mq: introduce qpop --check qpop --check let you qpop with uncommitted files if they do not intersect with files touched by the popped patches.

pager: check if signal.SIGPIPE exists We have to check for signal.SIGPIPE before we attempt to set it.

diffhelpers: harden testhunk

patch: fix segfault against unified diffs which start line is zero Since 2b1ec74c961f, if a chunk starts with "@@ -0,1", oldstart turns into a negative value. Because diffhelpers.testhunk() doesn't expect negative bstart, it bypasses "alen > blen - bstart" condition and segfaults at "PyList_GET_ITEM(b, i + bstart)".

bugzilla: fix transport initialization on python 2.4

bisect: set HG_NODE when runing a command When running a command, set the environment variable HG_NODE to tell the command which changeset is being visited.