From 09c482fad11c769be38b2449f1056e264b701bb7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Batuhan=20Ta=C5=9Fkaya?=
 <47358913+isidentical@users.noreply.github.com>
Date: Mon, 30 Dec 2019 19:08:08 +0300
Subject: bpo-39019: Implement missing __class_getitem__ for
 SpooledTemporaryFile (GH-17560)

---
 Lib/tempfile.py                                              | 12 ++++++++++++
 Lib/test/test_tempfile.py                                    |  3 +++
 .../next/Library/2019-12-10-21-11-05.bpo-39019.YIlgZ7.rst    |  1 +
 3 files changed, 16 insertions(+)
 create mode 100644 Misc/NEWS.d/next/Library/2019-12-10-21-11-05.bpo-39019.YIlgZ7.rst

diff --git a/Lib/tempfile.py b/Lib/tempfile.py
index 6287554..448163f 100644
--- a/Lib/tempfile.py
+++ b/Lib/tempfile.py
@@ -643,6 +643,18 @@ class SpooledTemporaryFile:
                                    'encoding': encoding, 'newline': newline,
                                    'dir': dir, 'errors': errors}
 
+    def __class_getitem__(cls, type):
+        """Provide minimal support for using this class as generic
+        (for example in type annotations).
+
+        See PEP 484 and PEP 560 for more details. For example,
+        `SpooledTemporaryFile[str]` is a valid expression at runtime (type
+        argument `str` indicates whether the file is open in bytes or text
+        mode). Note, no type checking happens at runtime, but a static type
+        checker can be used.
+        """
+        return cls
+
     def _check(self, file):
         if self._rolled: return
         max_size = self._max_size
diff --git a/Lib/test/test_tempfile.py b/Lib/test/test_tempfile.py
index 232c5da..5fe9506 100644
--- a/Lib/test/test_tempfile.py
+++ b/Lib/test/test_tempfile.py
@@ -1229,6 +1229,9 @@ class TestSpooledTemporaryFile(BaseTestCase):
         self.assertTrue(f._rolled)
         self.assertEqual(os.fstat(f.fileno()).st_size, 20)
 
+    def test_class_getitem(self):
+        self.assertIs(tempfile.SpooledTemporaryFile[bytes],
+                      tempfile.SpooledTemporaryFile)
 
 if tempfile.NamedTemporaryFile is not tempfile.TemporaryFile:
 
diff --git a/Misc/NEWS.d/next/Library/2019-12-10-21-11-05.bpo-39019.YIlgZ7.rst b/Misc/NEWS.d/next/Library/2019-12-10-21-11-05.bpo-39019.YIlgZ7.rst
new file mode 100644
index 0000000..7bdf291
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2019-12-10-21-11-05.bpo-39019.YIlgZ7.rst
@@ -0,0 +1 @@
+Implement dummy ``__class_getitem__`` for :class:`tempfile.SpooledTemporaryFile`.
-- 
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