Commit d674fe6d authored by Aymeric Augustin's avatar Aymeric Augustin
Browse files

Used a regular lock for app registry population. 

Since the app registry is always populated before the first request is
processed, the situation described in #18251 for the old app cache
cannot happen any more.

Refs #18251, #21628.
parent 225a6ed2

django/apps/registry.py

+8 −5
Original line number Diff line number Diff line 
from collections import Counter, defaultdict, OrderedDict

import os

import sys

import threading

import warnings



from django.core.exceptions import ImproperlyConfigured

from django.utils import lru_cache

from django.utils.module_loading import import_lock

from django.utils._os import upath



from .base import AppConfig
@@ -44,6 +44,9 @@ class Apps(object): 
        # Whether the registry is populated.

        self.ready = False



        # Lock for thread-safe population.

        self._lock = threading.Lock()



        # Pending lookups for lazy relations.

        self._pending_lookups = {}
@@ -61,10 +64,10 @@ class Apps(object): 
        """

        if self.ready:

            return

        # Since populate() may be a side effect of imports, and since it will

        # itself import modules, an ABBA deadlock between threads would be

        # possible if we didn't take the import lock. See #18251.

        with import_lock():



        # populate() might be called by two threads in parallel on servers

        # that create threads before initializing the WSGI callable.

        with self._lock:

            if self.ready:

                return

django/utils/module_loading.py

+0 −13
Original line number Diff line number Diff line 
from __future__ import absolute_import  # Avoid importing `importlib` from this package.



from contextlib import contextmanager

import copy

import imp

from importlib import import_module
@@ -36,18 +35,6 @@ def import_by_path(dotted_path, error_prefix=''): 
    return attr





@contextmanager

def import_lock():

    """

    Context manager that aquires the import lock.

    """

    imp.acquire_lock()

    try:

        yield

    finally:

        imp.release_lock()





def autodiscover_modules(*args, **kwargs):

    """

    Auto-discover INSTALLED_APPS modules and fail silently when