From cda2a0abd78b97989ef815a13d3ff7fcd5817efc Mon Sep 17 00:00:00 2001
From: Blazej Michalik <blazej.michalik@nokia.com>
Date: Wed, 18 May 2022 22:26:32 +0200
Subject: [PATCH] Evaluate markers under environment with no extra

---
 CHANGELOG.rst         | 4 +++-
 packaging/markers.py  | 1 +
 tests/test_markers.py | 9 +++------
 3 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/CHANGELOG.rst b/CHANGELOG.rst
index 214326e2f..23b85d196 100644
--- a/CHANGELOG.rst
+++ b/CHANGELOG.rst
@@ -4,7 +4,9 @@ Changelog
 *unreleased*
 ~~~~~~~~~~~~
 
-No unreleased changes.
+* ``Marker.evaluate`` will now assume evaluation environment with empty ``extra``.
+  Evaluating markers like ``"extra == 'xyz'"`` without passing any extra in the
+  ``environment`` will no longer raise an exception.
 
 21.3 - 2021-11-17
 ~~~~~~~~~~~~~~~~~
diff --git a/packaging/markers.py b/packaging/markers.py
index 03d8cdefc..f97b0154f 100644
--- a/packaging/markers.py
+++ b/packaging/markers.py
@@ -274,6 +274,7 @@ def default_environment() -> Dict[str, str]:
     iver = format_full_version(sys.implementation.version)
     implementation_name = sys.implementation.name
     return {
+        "extra": "",
         "implementation_name": implementation_name,
         "implementation_version": iver,
         "os_name": os.name,
diff --git a/tests/test_markers.py b/tests/test_markers.py
index b1ccf63c6..28762f105 100644
--- a/tests/test_markers.py
+++ b/tests/test_markers.py
@@ -15,7 +15,6 @@
     Marker,
     Node,
     UndefinedComparison,
-    UndefinedEnvironmentName,
     default_environment,
     format_full_version,
 )
@@ -110,6 +109,7 @@ def test_matches_expected(self):
             )
 
         assert environment == {
+            "extra": "",
             "implementation_name": sys.implementation.name,
             "implementation_version": iver,
             "os_name": os.name,
@@ -253,11 +253,8 @@ def test_compare_markers_to_other_objects(self):
         # Markers should not be comparable to other kinds of objects.
         assert Marker("os_name == 'nt'") != "os_name == 'nt'"
 
-    def test_extra_with_no_extra_in_environment(self):
-        # We can't evaluate an extra if no extra is passed into the environment
-        m = Marker("extra == 'security'")
-        with pytest.raises(UndefinedEnvironmentName):
-            m.evaluate()
+    def test_environment_assumes_empty_extra(self):
+        assert Marker('extra == "im_valid"').evaluate() is False
 
     @pytest.mark.parametrize(
         ("marker_string", "environment", "expected"),