bugzilla: add a rest api backend (usable with bugzilla 5.0+) Add support for the bugzilla rest api documented at https://wiki.mozilla.org/Bugzilla:REST_API and at https://bugzilla.readthedocs.io/en/latest/ This backend has the following benefits: * It supports the bugzilla api keys so hgrc does not need to contain a user's bugzilla password * Works with Mercurial's "hostfingerprints" support making handling bugzilla instances with self-signed certs easier * Does not use xmlrpc ;-) Adds configuration item 'apikey' in [bugzilla] section. My major concern with these patches is if the approach to HTTP access is the right way for an extension and if hooking into request object and the overriding the get_method to perform PUT requests was a sensible approach. # no-check-commit

keepalive: honor urllib2 style get_method overrides In urllib2 docs and discussions it can be found that in order to make a request other than GET or POST the get_method of a Request object can be overriden. Make Mercurial's internal version of this honor the return value of get_method. Please see the followup patch to the bugzilla extension for the reason for this change. Marking RFC because I'm not entirely sure this is the right way make the HTTP requests.

lock: include Linux pid namespace identifier in prefix Previously, the lock only contains a hostname as an attempt to detect pid namespace difference. However, that's not enough on modern Linux - a single hostname could have different pid namespaces. That means if people run hg inside different PID namespaces with a same UTS namespae, the lock would be broken - an hg proccess in pid namespace A will think the lock having a "random" pid in pid namespace B is "dead" and remove it. This patch solves the above issue by appending an PID namespace identifier of the current process to the lock prefix ("hostname"). It depends on /proc being mounted properly. But I don't think there is a better way to get pid namespace identifier reliably.

lock: move lock._host calculation to a function This allows customization per platform. See the next patch for why.