rust: update `clap` to the latest 4.x version
This brings in more up-to-date dependencies, some bug fixes (none of which are
relevant yet), and slightly improved compile times.
Tests if hgweb can run without touching sys.stdin, as is required
by the WSGI standard and strictly implemented by mod_wsgi.
$ hg init repo
$ cd repo
$ echo foo > bar
$ hg add bar
$ hg commit -m "test"
$ cat > request.py <<EOF
> import os
> import sys
> from mercurial import (
> dispatch,
> encoding,
> hg,
> ui as uimod,
> util,
> )
> from mercurial.utils import (
> procutil,
> )
> ui = uimod.ui
> from mercurial.hgweb import hgweb_mod
> stringio = util.stringio
>
> class FileLike(object):
> def __init__(self, real):
> self.real = real
> def fileno(self):
> print >> sys.__stdout__, 'FILENO'
> return self.real.fileno()
> def read(self):
> print >> sys.__stdout__, 'READ'
> return self.real.read()
> def readline(self):
> print >> sys.__stdout__, 'READLINE'
> return self.real.readline()
>
> sys.stdin = FileLike(sys.stdin)
> errors = stringio()
> input = stringio()
> output = stringio()
>
> def startrsp(status, headers):
> print('---- STATUS')
> print(status)
> print('---- HEADERS')
> print([i for i in headers if i[0] != 'ETag'])
> print('---- DATA')
> return output.write
>
> env = {
> 'wsgi.version': (1, 0),
> 'wsgi.url_scheme': 'http',
> 'wsgi.errors': errors,
> 'wsgi.input': input,
> 'wsgi.multithread': False,
> 'wsgi.multiprocess': False,
> 'wsgi.run_once': False,
> 'REQUEST_METHOD': 'GET',
> 'SCRIPT_NAME': '',
> 'PATH_INFO': '',
> 'QUERY_STRING': '',
> 'SERVER_NAME': '$LOCALIP',
> 'SERVER_PORT': os.environ['HGPORT'],
> 'SERVER_PROTOCOL': 'HTTP/1.0'
> }
>
> i = hgweb_mod.hgweb(b'.')
> for c in i(env, startrsp):
> pass
> sys.stdout.flush()
> procutil.stdout.write(b'---- ERRORS\n')
> procutil.stdout.write(b'%s\n' % errors.getvalue())
> print('---- OS.ENVIRON wsgi variables')
> print(sorted([x for x in os.environ if x.startswith('wsgi')]))
> print('---- request.ENVIRON wsgi variables')
> with i._obtainrepo() as repo:
> print(sorted([encoding.strfromlocal(x) for x in repo.ui.environ
> if x.startswith(b'wsgi')]))
> EOF
$ "$PYTHON" request.py
---- STATUS
200 Script output follows
---- HEADERS
[('Content-Type', 'text/html; charset=ascii')]
---- DATA
---- ERRORS
---- OS.ENVIRON wsgi variables
[]
---- request.ENVIRON wsgi variables
['wsgi.errors', 'wsgi.input', 'wsgi.multiprocess', 'wsgi.multithread', 'wsgi.run_once', 'wsgi.url_scheme', 'wsgi.version']
$ cd ..