rust-chg: modernize entry function Finally the entire build passes. There's a bug that run() no longer waits for the spawned pager, which will be fixed by the next patch. Differential Revision: https://phab.mercurial-scm.org/D8448

rust-chg: reimplement locator by using async/await and tokio-0.2 connect_spawned() is rewritten from scratch by using std::process. Before, it would select completion of either connection or server process. New code could be implemented as such, but it's much simpler to occasionally run try_wait() to detect server death. Differential Revision: https://phab.mercurial-scm.org/D8447

rust-chg: reimplement ChgClientExt as ChgClient wrapper ChgClient is no longer an extension trait because: a. Client object is not consumed and recreated in future-0.3 world, which unblocks writing a simple wrapper struct. b. async fn isn't allowed in trait. Overall, the API should become simpler. Differential Revision: https://phab.mercurial-scm.org/D8446

rust-chg: reimplement run_command operation as async function The crafted state machine is no longer needed thanks to async/await. The state machine is basically rewritten as follows: - Ready(..) -> return .. - PollAgain(..) -> run .. and await - Err(..) -> return Err(..) Differential Revision: https://phab.mercurial-scm.org/D8445

rust-chg: reimplement uihandler by using async-trait and tokio-0.2 We no longer have to consume self and arguments. Differential Revision: https://phab.mercurial-scm.org/D8444

rust-chg: have attach_io() simply take reference of AsRawFd object We no longer have to deal with the restriction of the Future type. Before, these file objects couldn't be references and that's the only reason why we had to make stderr an Option<T>. This fixes future type deduction issue of stderr = None, where rustc would complain that T of Option<T> couldn't be deduced. Differential Revision: https://phab.mercurial-scm.org/D8443

rust-status: check for '.hg' regardless of file type (issue6300) '.hg' would show up in `hg status` if were a symlink. Differential Revision: https://phab.mercurial-scm.org/D8461

rust: remove extra empty line This is a gratuitous cleanup. Differential Revision: https://phab.mercurial-scm.org/D8460

upgrade: properly filter action depending on planned work The `determineactions` function filters out deficiency that are not scheduled to be fixed by the target repository configuration. However it only did so for requirement we currently support, letting other actions for unsupported requirement through even if the target repo configuration did not request it. As a result the output of the command was easily polluted by experimental feature with no upgrade support. We rework the code to still filter out requirement based action without the faulty filtering. Differential Revision: https://phab.mercurial-scm.org/D8427

nodemap: skip persistent nodemap warming for revlog not using it Before this patch, the usual checking (especially, inline-ess) were not performed when warming the cache through `hg debugupdatecache`. This is now fixed. Differential Revision: https://phab.mercurial-scm.org/D8408

wait-on-file: adjust the timer counter The wait performed in increment of 0.01 second, but the timer was expressed in second. So we did not wait 20s, we waited 0.2 second. Internally we adjust the counter to be expressed in centisecond. This prevent some flackyness in the test. Differential Revision: https://phab.mercurial-scm.org/D8453

packaging: add docutils as dependency The previous commit revealed that attempting to run `python setup.py build_doc` from the packaging virtualenv failed due to missing docutils package. We didn't notice this before because py2exe Windows packaging appears to use a Python from another virtualenv (which does include docutils) to invoke setup.py. I discovered this as part of implementing packaging outside of that virtualenv environment. Differential Revision: https://phab.mercurial-scm.org/D8470

setup: use sysstr() on process output Otherwise we get a str-bytes mismatch on Python 3 if an error occurs. Differential Revision: https://phab.mercurial-scm.org/D8469

automation: install latest Python versions in Linux Staying up to date. Keeping parity with the Windows environment. Differential Revision: https://phab.mercurial-scm.org/D8467

contrib: update to latest Python 2.7, 3.7, and 3.8 We would ideally update the 3.5 and 3.6 versions as well. But Python didn't generate exe installers for newer versions for some reason. Differential Revision: https://phab.mercurial-scm.org/D8466