tests/test-hgweb-non-interactive.t

config: explicitly track the use of the standard default value

We introduce a small object used to detect that no specific default value has
been passed to 'ui.config'. We need this explicit special value since "None" is
a valid and common default value.

The end goal here is to make progress on a centralised and explicit declaration
of the available config option. A first good usecase for this are "default"
value.  Before starting looking further down this alley we needs to rework the
handling of default value in the 'ui' object to have all configxyz methods going
through the same logic. This is the first changeset on this trek.

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
  > from __future__ import absolute_import
  > import os
  > import sys
  > from mercurial import (
  >     dispatch,
  >     hg,
  >     ui as uimod,
  >     util,
  > )
  > ui = uimod.ui
  > from mercurial.hgweb.hgweb_mod import (
  >     hgweb,
  > )
  > 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('.')
  > for c in i(env, startrsp):
  >     pass
  > print '---- ERRORS'
  > print 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([x for x in repo.ui.environ if x.startswith('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 ..