view mercurial/hgweb/wsgicgi.py @ 24136:46d6cdfce4bf

hgweb: use introrev() for finding parents (issue4506)

The issue is titled "filtered revision 'XXX' (not in 'served' subset)" and that
is the error message you sometimes get when trying to look at a file (/file or
/annotate) in hgweb. For example:

http://hg.intevation.org/mercurial/crew/file/90cf454edd70/mercurial/cmdutil.py

This happens when a parent revision for a file is hidden, thus it is
not 'served' and isn't accessible in hgweb by default. When hgweb tries to
access such changeset, it produces the error and HTTP status code 404.

Another detail is that the parents() function, that is used in multiple places
in hgweb, sometimes returned changesets that were obsoleted by the current
changeset for the file. For example, when using rebase with evolve and rebasing
a divergent changeset that introduces a file on top of current branch. Or
grafting a change and making the new grafted changeset obsolete the source
(shown in the test case). The result is the same - the obsoleted changeset was
mistakingly returned from parents(), even though it's not a parent and the only
link to the new changeset is an obsoletion marker (and rebase/graft metadata?
not sure it matters).

The problem is fixed by using introrev() instead of linkrev() for finding
parents. This prevents parents() function from returning unrelated obsolete
changesets.

The test case prepares a separate repo because (afaict) all other test cases
never reuse file names, so there are no files that were changed in multiple
changesets. So no previously available files have obsolete changesets in their
history.

# hgweb/wsgicgi.py - CGI->WSGI translator
#
# Copyright 2006 Eric Hopper <[e-mail]>
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2 or any later version.
#
# This was originally copied from the public domain code at
# http://www.python.org/dev/peps/pep-0333/#the-server-gateway-side

import os, sys
from mercurial import util
from mercurial.hgweb import common

def launch(application):
    util.setbinary(sys.stdin)
    util.setbinary(sys.stdout)

    environ = dict(os.environ.iteritems())
    environ.setdefault('PATH_INFO', '')
    if environ.get('SERVER_SOFTWARE', '').startswith('Microsoft-IIS'):
        # IIS includes script_name in PATH_INFO
        scriptname = environ['SCRIPT_NAME']
        if environ['PATH_INFO'].startswith(scriptname):
            environ['PATH_INFO'] = environ['PATH_INFO'][len(scriptname):]

    stdin = sys.stdin
    if environ.get('HTTP_EXPECT', '').lower() == '100-continue':
        stdin = common.continuereader(stdin, sys.stdout.write)

    environ['wsgi.input'] = stdin
    environ['wsgi.errors'] = sys.stderr
    environ['wsgi.version'] = (1, 0)
    environ['wsgi.multithread'] = False
    environ['wsgi.multiprocess'] = True
    environ['wsgi.run_once'] = True

    if environ.get('HTTPS', 'off').lower() in ('on', '1', 'yes'):
        environ['wsgi.url_scheme'] = 'https'
    else:
        environ['wsgi.url_scheme'] = 'http'

    headers_set = []
    headers_sent = []
    out = sys.stdout

    def write(data):
        if not headers_set:
            raise AssertionError("write() before start_response()")

        elif not headers_sent:
            # Before the first output, send the stored headers
            status, response_headers = headers_sent[:] = headers_set
            out.write('Status: %s\r\n' % status)
            for header in response_headers:
                out.write('%s: %s\r\n' % header)
            out.write('\r\n')

        out.write(data)
        out.flush()

    def start_response(status, response_headers, exc_info=None):
        if exc_info:
            try:
                if headers_sent:
                    # Re-raise original exception if headers sent
                    raise exc_info[0](exc_info[1], exc_info[2])
            finally:
                exc_info = None     # avoid dangling circular ref
        elif headers_set:
            raise AssertionError("Headers already set!")

        headers_set[:] = [status, response_headers]
        return write

    content = application(environ, start_response)
    try:
        for chunk in content:
            write(chunk)
        if not headers_sent:
            write('')   # send headers now if body was empty
    finally:
        getattr(content, 'close', lambda : None)()