setup: prefer using the system hg to interact with the local repository Add a findhg() function that tries to be smarter about figuring out how to run hg for examining the local repository. It first tries running "hg" from the user's PATH, with the default HGRCPATH settings intact, but with HGPLAIN enabled. This will generally use the same version of mercurial and the same settings used to originally clone the repository, and should have a higher chance of working successfully than trying to run the hg script from the local repository. If that fails findhg() falls back to the existing behavior of running the local hg script.

setup: replace runhg() with an hgcommand helper class Replace the runhg() function with an hgcommand helper class. hgcommand has as run() function similar to runhg(), but no longer requires the caller to pass in the exact path to python and the hg script, and the environment settings for invoking hg. For now this diff contains no behavior changes, but in the future this will make it easier for the hgcommand helper class to more intelligently figure out the proper way to invoke hg.

setup: move environment computation into a helper function Add a helper function to compute the environment used for invoking mercurial, rather than doing this computation entirely at global scope. This will make it easier to do some subsequent refactoring.

setup: update runcmd() to also return the exit status Update the runcmd() helper function so it also returns the process exit status. This allows callers to more definitively determine if a command failed, rather than testing only for the presence of data on stderr. I don't expect this to have any behavioral changes for now: the commands invoked by setup generally should print data on stderr if and only if they failed.

setup: fail if we cannot determine the version number If running hg fails, exit the setup script unsuccessfully, rather than proceeding to use a bogus version of "+0-". Using an invalid version number causes various tests to fail later. Failing early makes it easier to identify the source of the problem. It is currently easy for setup.py to fail this way since it sets HGRCPTH to the empty string before running "hg", which may often disable extensions necessary to interact with the local repository.

smartset: fix generatorset.last() to not return the first element (issue5609)

strip: respect the backup option in stripcallback The backup option was mistakenly ignored. It should be respected. Thanks Martin von Zweigbergk for finding this out!

py3: use pycompat.bytestr() to convert str to bytes

py3: pass the memoryview object into bytes() to get the value

py3: use pycompat.bytestr instead of str