rust-index: document safety invariants being upheld for every `unsafe` block
We've added a lot of `unsafe` code that shares Rust structs with Python.
While this is unfortunate, it is also unavoidable, so let's at least
systematically explain why each call to `unsafe` is sound.
If any of the unsafe code ends up being wrong (because everyone screws up
at some point), this change at least continues the unspoken rule of always
explaining the need for `unsafe`, so we at least get a chance to think.
#!/usr/bin/env python3
#
# An example hgweb CGI script, edit as necessary
# See also https://mercurial-scm.org/wiki/PublishingRepositories
# Path to repo or hgweb config to serve (see 'hg help hgweb')
config = b"/path/to/repo/or/config"
# Uncomment and adjust if Mercurial is not installed system-wide
# (consult "installed modules" path from 'hg debuginstall'):
# import sys; sys.path.insert(0, "/path/to/python/lib")
from mercurial import demandimport
demandimport.enable()
from mercurial.hgweb import hgweb, wsgicgi
application = hgweb(config)
wsgicgi.launch(application)