debugcommands: move 'debuggetbundle' in the new module

debugcommands: move 'debugfsinfo' in the new module

debugcommands: move 'debugfileset' in the new module

censor: flag internal documentation

shelve: make --keep option survive user intervention (issue5431) Currently if user runs 'hg unshelve --keep' and merge conflicts occur, the information about --keep provided by user is lost and shelf is deleted after 'hg unshelve --continue'. This is obviously not desired, so this patch fixes it.

worker: use os._exit for posix worker in all cases Like commandserver, the worker should never run other resource cleanup logic. Previously this is not true for workers if they have exceptions other than KeyboardInterrupt. This actually caused a real-world deadlock with remotefilelog: 1. remotefilelog/fileserverclient creates a sshpeer. pipei/o/e get created. 2. worker inherits that sshpeer's pipei/o/e. 3. worker runs sshpeer.cleanup (only happens without os._exit) 4. worker closes pipeo/i, which will normally make the sshpeer read EOF from its stdin and exit. But the master process still have pipeo, so no EOF. 5. worker reads pipee (stderr of sshpeer), which never completes because the ssh process does not exit, does not close its stderr. 6. master waits for all workers, which never completes because they never complete sshpeer.cleanup. This could also be addressed by closing these fds after fork, which is not easy because Python 2.x does not have an official "afterfork" hook. Hacking os.fork is also ugly. Besides, sshpeer is probably not the only troublemarker. The patch changes _posixworker so all its code paths will use os._exit to avoid running unwanted resource clean-ups.

dispatch: move part of callcatch to scmutil Per discussion at 39149b6036e6 [1], we need "callcatch" in worker.py. Move it to scmutil.py to avoid cycles. Note that dispatch's callcatch handles some additional high-level exceptions related to config parsing, and commands. Moving them to scmutil will make scmutil depend on "commands" or require "_formatparse" and "_getsimilar" (and "difflib") to be moved as well. In the worker use-case, it is forked when config and commands are fully loaded. So it should not care about those exceptions. [1]: https://www.mercurial-scm.org/pipermail/mercurial-devel/2016-August/087116.html

py3: use pycompat.getcwd() instead of os.getcwd() We have pycompat.getcwd() which returns bytes path on Python 3. This patch changes most of the occurences of the os.getcwd() with pycompat one.

debugcommands: move 'debugextensions' to the new module

debugcommands: move 'debugdiscovery' in the module And a lot of imports with it.

debugcommands: move 'debugdate' in the new module

debugcommands: move 'debugrevlogopts' into the new module This move contains the first reference to debugrevlogopts in debugcommands.py. We'll eventually want to move that over. We hold off for now because it would introduce a module import cycle.

debugcommands: move 'debugdag' into the new module

chgserver: make it a core module and drop extension flags It was an extension just because there were several dependency cycles I needed to address. I don't add 'chgserver' to extensions._builtin since chgserver is considered an internal extension so nobody should enable it by their config.

chgserver: delay importing commands and dispatch modules This is a workaround for future import cycle: dispatch -> commands -> server -> chgserver -> commands. Some of the problems can be fixed later on pager and chg refactoring.