tests/test-hgweb-non-interactive.t

sshpeer: don't read from stderr when that behavior is disabled

We previously prevented the creation of doublepipe instances when
we're not supposed to automatically read from stderr. However,
there were other automatic calls to read from stderr that were
undermining this effort.

This commit prevents all automatic reads from stderr from occurring
when they are supposed to be disabled.

Because stderr is no longer being read, we need to call "readavailable"
from tests so stderr is read from.

Test output changes because stderr is now always (manually) read after
stdout. And, since sshpeer no longer automatically tends to stderr,
no "remote: " messages are printed. This should fix non-deterministic
test output.

FWIW, doublepipe automatically reads from stderr when reading from
stdout, so I'm not sure some of these calls to self._readerr() are
even needed.

Differential Revision: https://phab.mercurial-scm.org/D2571

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 ..