From 85f824f49d69177f68245b9788acaf5ace97afb7 Mon Sep 17 00:00:00 2001
From: Melissa Li <li.melissa.kun@gmail.com>
Date: Sat, 27 Feb 2021 21:31:09 -0500
Subject: [PATCH 1/3] handle AttributeError by raising DisutilsSetupError in
 check_specifier

---
 setuptools/dist.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/setuptools/dist.py b/setuptools/dist.py
index c31020f0c4..6ae3886b1f 100644
--- a/setuptools/dist.py
+++ b/setuptools/dist.py
@@ -292,7 +292,7 @@ def check_specifier(dist, attr, value):
     """Verify that value is a valid version specifier"""
     try:
         packaging.specifiers.SpecifierSet(value)
-    except packaging.specifiers.InvalidSpecifier as error:
+    except (packaging.specifiers.InvalidSpecifier, AttributeError) as error:
         tmpl = (
             "{attr!r} must be a string "
             "containing valid version specifiers; {error}"

From 20ced7533c2b737e9d99deacd97633f84b26567d Mon Sep 17 00:00:00 2001
From: Melissa Li <li.melissa.kun@gmail.com>
Date: Sun, 28 Feb 2021 00:59:58 -0500
Subject: [PATCH 2/3] test check_specifier

---
 setuptools/tests/test_dist.py | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/setuptools/tests/test_dist.py b/setuptools/tests/test_dist.py
index cb47fb5848..e4bba47bce 100644
--- a/setuptools/tests/test_dist.py
+++ b/setuptools/tests/test_dist.py
@@ -9,6 +9,7 @@
     _get_unpatched,
     check_package_data,
     DistDeprecationWarning,
+    check_specifier,
 )
 from setuptools import sic
 from setuptools import Distribution
@@ -323,3 +324,15 @@ def test_check_package_data(package_data, expected_message):
         with pytest.raises(
                 DistutilsSetupError, match=re.escape(expected_message)):
             check_package_data(None, str('package_data'), package_data)
+
+
+def test_check_specifier():
+    # valid specifier value
+    attrs = {'name': 'foo', 'python_requires': '>=3.0, !=3.1'}
+    dist = Distribution(attrs)
+    check_specifier(dist, attrs, attrs['python_requires'])
+
+    # invalid specifier value
+    attrs = {'name': 'foo', 'python_requires': ['>=3.0', '!=3.1']}
+    with pytest.raises(DistutilsSetupError):
+        dist = Distribution(attrs)

From adf32a23250c56b8c3856c768b5776bb78f695a3 Mon Sep 17 00:00:00 2001
From: Melissa Li <li.melissa.kun@gmail.com>
Date: Sun, 28 Feb 2021 02:11:42 -0500
Subject: [PATCH 3/3] Add changelog

---
 changelog.d/1932.change.rst | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 changelog.d/1932.change.rst

diff --git a/changelog.d/1932.change.rst b/changelog.d/1932.change.rst
new file mode 100644
index 0000000000..a7af5b72ac
--- /dev/null
+++ b/changelog.d/1932.change.rst
@@ -0,0 +1 @@
+Handled :code:`AttributeError` by raising :code:`DistutilsSetupError` in :code:`dist.check_specifier()` when specifier is not a string -- by :user:`melissa-kun-li`
\ No newline at end of file