From c01b478d43e1be2e7c41a6a636b0f6bfc61444e9 Mon Sep 17 00:00:00 2001
From: Bonifacio de Oliveira <bonifacio.segundo@gmail.com>
Date: Sat, 12 Jun 2021 17:13:02 -0300
Subject: [PATCH 1/4] add category type check Co-authored-by: Vajrasky Kok

---
 Lib/test/test_warnings/__init__.py | 7 +++++++
 Lib/warnings.py                    | 1 +
 2 files changed, 8 insertions(+)

diff --git a/Lib/test/test_warnings/__init__.py b/Lib/test/test_warnings/__init__.py
index 4b1b4e193cb165b..e2becb74a1c1afc 100644
--- a/Lib/test/test_warnings/__init__.py
+++ b/Lib/test/test_warnings/__init__.py
@@ -342,6 +342,13 @@ def test_filterwarnings_duplicate_filters(self):
                 "the beginning of list"
             )
 
+    def test_simplefilter_invalid_category(self):
+        with original_warnings.catch_warnings(record=True, module=self.module):
+            invalid_category = 'spam'
+            with self.assertRaises(AssertionError) as cm:
+                self.module.simplefilter("once", invalid_category)
+            self.assertEqual(str(cm.exception), "category must be a class")
+
     def test_simplefilter_duplicate_filters(self):
         with original_warnings.catch_warnings(module=self.module):
             self.module.resetwarnings()
diff --git a/Lib/warnings.py b/Lib/warnings.py
index 691ccddfa450ad2..5df7c8c29a7cc90 100644
--- a/Lib/warnings.py
+++ b/Lib/warnings.py
@@ -176,6 +176,7 @@ def simplefilter(action, category=Warning, lineno=0, append=False):
                       "once"), "invalid action: %r" % (action,)
     assert isinstance(lineno, int) and lineno >= 0, \
            "lineno must be an int >= 0"
+    assert isinstance(category, type), "category must be a class"
     _add_filter(action, None, category, None, lineno, append=append)
 
 def _add_filter(*item, append):

From db698e4a88b56b7687587f06298ef5daac858a0b Mon Sep 17 00:00:00 2001
From: "blurb-it[bot]" <43283697+blurb-it[bot]@users.noreply.github.com>
Date: Sat, 12 Jun 2021 20:21:41 +0000
Subject: [PATCH 2/4] =?UTF-8?q?=F0=9F=93=9C=F0=9F=A4=96=20Added=20by=20blu?=
 =?UTF-8?q?rb=5Fit.?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 .../NEWS.d/next/Library/2021-06-12-20-21-40.bpo-16845.SqR6Ik.rst | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 Misc/NEWS.d/next/Library/2021-06-12-20-21-40.bpo-16845.SqR6Ik.rst

diff --git a/Misc/NEWS.d/next/Library/2021-06-12-20-21-40.bpo-16845.SqR6Ik.rst b/Misc/NEWS.d/next/Library/2021-06-12-20-21-40.bpo-16845.SqR6Ik.rst
new file mode 100644
index 000000000000000..ac2eae903796616
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2021-06-12-20-21-40.bpo-16845.SqR6Ik.rst
@@ -0,0 +1 @@
+add category type check to warnings.simplefilter
\ No newline at end of file

From 90ec5db3dd7480f97efc4988062aec1655dab4d4 Mon Sep 17 00:00:00 2001
From: Joannah Nanjekye <33177550+nanjekyejoannah@users.noreply.github.com>
Date: Sun, 13 Jun 2021 10:11:07 -0300
Subject: [PATCH 3/4] Update 2021-06-12-20-21-40.bpo-16845.SqR6Ik.rst

---
 .../next/Library/2021-06-12-20-21-40.bpo-16845.SqR6Ik.rst       | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Misc/NEWS.d/next/Library/2021-06-12-20-21-40.bpo-16845.SqR6Ik.rst b/Misc/NEWS.d/next/Library/2021-06-12-20-21-40.bpo-16845.SqR6Ik.rst
index ac2eae903796616..b6856266e841da6 100644
--- a/Misc/NEWS.d/next/Library/2021-06-12-20-21-40.bpo-16845.SqR6Ik.rst
+++ b/Misc/NEWS.d/next/Library/2021-06-12-20-21-40.bpo-16845.SqR6Ik.rst
@@ -1 +1 @@
-add category type check to warnings.simplefilter
\ No newline at end of file
+Add category type check to `warnings.simplefilter`.

From 291fdcc9a1aa431f9e83ebf21f42c9a432c2cc20 Mon Sep 17 00:00:00 2001
From: Joannah Nanjekye <33177550+nanjekyejoannah@users.noreply.github.com>
Date: Sun, 13 Jun 2021 11:41:29 -0300
Subject: [PATCH 4/4] Update 2021-06-12-20-21-40.bpo-16845.SqR6Ik.rst

---
 .../next/Library/2021-06-12-20-21-40.bpo-16845.SqR6Ik.rst       | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Misc/NEWS.d/next/Library/2021-06-12-20-21-40.bpo-16845.SqR6Ik.rst b/Misc/NEWS.d/next/Library/2021-06-12-20-21-40.bpo-16845.SqR6Ik.rst
index b6856266e841da6..8678300e12a5db6 100644
--- a/Misc/NEWS.d/next/Library/2021-06-12-20-21-40.bpo-16845.SqR6Ik.rst
+++ b/Misc/NEWS.d/next/Library/2021-06-12-20-21-40.bpo-16845.SqR6Ik.rst
@@ -1 +1 @@
-Add category type check to `warnings.simplefilter`.
+Add category type check to warnings.simplefilter.