errors: set detailed exit code to 100 for some remote errors This is per https://www.mercurial-scm.org/wiki/ErrorCategoriesPlan. Differential Revision: https://phab.mercurial-scm.org/D9309

errors: catch urllib errors specifically instead of using safehasattr() Before this patch, we would catch `IOError` and `OSError` and check if the instance had a `.code` member (indicates `HTTPError`) or a `.reason` member (indicates the more generic `URLError`). It seems to me that can simply catch those exception specifically instead, so that's what this code does. The existing code is from fbe8834923c5 (commands: report http exceptions nicely, 2005-06-17), so I suspect it's just that there was no `urllib2` (where `URLError` lives) back then. The old code mentioned `SSLError` in a comment. The new code does *not* try to catch that. The documentation for `ssl.SSLError` says that it has a `.reason` property, but `python -c 'import ssl; print(dir(ssl.SSLError("foo", Exception("bar"))))` doesn't mention that property on either Python 2 or Python 3 on my system. It also seems that `sslutil` is pretty careful about converting `ssl.SSLError` to `error.Abort`. It also is carefult to not assume that instances of the exception have a `.reason`. So I at least don't want to catch `ssl.SSLError` and handle it the same way as `URLError` because that would likely result in a crash. I also wonder if we don't need to handle it at all (because `sslutil` might handle all the cases). It's now early in the release cycle, so perhaps we can just see how it goes? Differential Revision: https://phab.mercurial-scm.org/D9318

errors: raise InputError in fancyopts If a value of wrong type is passed to a command line flag, that's cleary an InputError. Differential Revision: https://phab.mercurial-scm.org/D9308

packaging: switch centos 7 packaging to python 3 Differential Revision: https://phab.mercurial-scm.org/D9293

packaging: remove centos5 and centos6 support Differential Revision: https://phab.mercurial-scm.org/D9292

test-filecache: use sys.executable to call python As was mentioned in c102b704edb5, test scripts calling 'python' or 'python3' might use the wrong python. For test-filecache.py, this causes a failed test on CentOS 7. Differential Revision: https://phab.mercurial-scm.org/D9295

make: add a pyoxidizer target Differential Revision: https://phab.mercurial-scm.org/D9291

pyoxidizer: switch to modern config using run_command instead of run_mode Differential Revision: https://phab.mercurial-scm.org/D9290

pyoxidizer: default to one-file binary on non-Windows platforms Windows has some extra constraints that require a multi-file install, but we expect folks to use an MSI or similar installer there so it's less of a big deal. Differential Revision: https://phab.mercurial-scm.org/D9289

global: use python3 in shebangs Python 3 is the future. We want Python scripts to be using Python 3 by default. This change updates all `#!/usr/bin/env python` shebangs to use `python3`. Does this mean all scripts use or require Python 3: no. In the test environment, the `PATH` environment variable in tests is updated to guarantee that the Python executable used to run run-tests.py is used. Since test scripts all now use `#!/usr/bin/env python3`, we had to update this code to install a `python3` symlink instead of `python`. It is possible there are some random scripts now executed with the incorrect Python interpreter in some contexts. However, I would argue that this was a pre-existing bug: we should almost always be executing new Python processes using the `sys.executable` from the originating Python script, as `python` or `python3` won't guarantee we'll use the same interpreter. Differential Revision: https://phab.mercurial-scm.org/D9273