Fix collections.abc imports for Python 3.9 (#7707)

* Fix collections.abc imports for Python 3.9

* Update AUTHORS.md

* No longer ignore collections.abc deprecation warning

* Update changelog

* Remove outdated comment

* Disabling no-name-in-module not needed as linting is on Python 3

AUTHORS.md

@@ -100,6 +100,7 @@ Authors
 * [Harlan Lieberman-Berg](https://github.com/hlieberman)
 * [Henri Salo](https://github.com/fgeek)
 * [Henry Chen](https://github.com/henrychen95)
+* [Hugo van Kemenade](https://github.com/hugovk)
 * [Ingolf Becker](https://github.com/watercrossing)
 * [Jaap Eldering](https://github.com/eldering)
 * [Jacob Hoffman-Andrews](https://github.com/jsha)

certbot/CHANGELOG.md

@@ -15,7 +15,7 @@ Certbot adheres to [Semantic Versioning](https://semver.org/).
 
 ### Fixed
 
-*
+* Fix collections.abc imports for Python 3.9.
 
 More details about these changes can be found on our GitHub repo.
 

certbot/certbot/_internal/plugins/disco.py

@@ -13,6 +13,12 @@ from certbot import errors
 from certbot import interfaces
 from certbot._internal import constants
 
+try:
+    # Python 3.3+
+    from collections.abc import Mapping
+except ImportError:  # pragma: no cover
+    from collections import Mapping
+
 logger = logging.getLogger(__name__)
 
 
@@ -178,7 +184,7 @@ class PluginEntryPoint(object):
         return "\n".join(lines)
 
 
-class PluginsRegistry(collections.Mapping):
+class PluginsRegistry(Mapping):
     """Plugins registry."""
 
     def __init__(self, plugins):

pytest.ini

@@ -4,10 +4,6 @@
 [pytest]
 # In general, all warnings are treated as errors. Here are the exceptions:
 #   1- decodestring: https://github.com/rthalley/dnspython/issues/338
-#   2- ignore warn for importing abstract classes from collections instead of collections.abc,
-#      too much third party dependencies are still relying on this behavior,
-#      but it should be corrected to allow Certbot compatibility with Python >= 3.8
 filterwarnings =
     error
     ignore:decodestring:DeprecationWarning
-    ignore:.*collections\.abc:DeprecationWarning