From 66b268ae3dad115086a86a1f484aa26ec898f396 Mon Sep 17 00:00:00 2001
From: Andrzej Mateja <mateja.and@gmail.com>
Date: Wed, 2 Jun 2021 17:14:55 +0200
Subject: [PATCH 1/4] bpo-44289: Keep argument file object's current position
 in tarfile.is_tarifle function.

---
 Lib/tarfile.py           |  2 ++
 Lib/test/test_tarfile.py | 12 ++++++++++++
 2 files changed, 14 insertions(+)

diff --git a/Lib/tarfile.py b/Lib/tarfile.py
index 18d415adf54418..331e24adf6388e 100755
--- a/Lib/tarfile.py
+++ b/Lib/tarfile.py
@@ -2484,7 +2484,9 @@ def is_tarfile(name):
     """
     try:
         if hasattr(name, "read"):
+            pos = name.tell()
             t = open(fileobj=name)
+            name.seek(pos)
         else:
             t = open(name)
         t.close()
diff --git a/Lib/test/test_tarfile.py b/Lib/test/test_tarfile.py
index 817e6f17997121..0928b5ad8e2e48 100644
--- a/Lib/test/test_tarfile.py
+++ b/Lib/test/test_tarfile.py
@@ -352,6 +352,18 @@ def test_is_tarfile_valid(self):
         with open(self.tarname, "rb") as fobj:
             self.assertTrue(tarfile.is_tarfile(io.BytesIO(fobj.read())))
 
+    def test_is_tarfile_keeps_position(self):
+        # Test for issue44289: tarfile.is_tarfile() modifies
+        # file object's current position
+        with open(self.tarname, "rb") as fobj:
+            tarfile.is_tarfile(fobj)
+            self.assertEqual(fobj.tell(), 0)
+
+        with open(self.tarname, "rb") as fobj:
+            file_like = io.BytesIO(fobj.read())
+            tarfile.is_tarfile(file_like)
+            self.assertEqual(file_like.tell(), 0)
+
     def test_empty_tarfile(self):
         # Test for issue6123: Allow opening empty archives.
         # This test checks if tarfile.open() is able to open an empty tar

From bdb1ff92d62dbf8d5c927efe631f4c09ca8afd9b Mon Sep 17 00:00:00 2001
From: "blurb-it[bot]" <43283697+blurb-it[bot]@users.noreply.github.com>
Date: Wed, 2 Jun 2021 19:47:47 +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/2021-06-02-19-47-46.bpo-44289.xC5kuV.rst | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 Misc/NEWS.d/next/Library/2021-06-02-19-47-46.bpo-44289.xC5kuV.rst

diff --git a/Misc/NEWS.d/next/Library/2021-06-02-19-47-46.bpo-44289.xC5kuV.rst b/Misc/NEWS.d/next/Library/2021-06-02-19-47-46.bpo-44289.xC5kuV.rst
new file mode 100644
index 00000000000000..d2feab9bda49b2
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2021-06-02-19-47-46.bpo-44289.xC5kuV.rst
@@ -0,0 +1 @@
+Keep argument file object's current position in tarfile.is_tarifle method.
\ No newline at end of file

From 7be28192b481afd2fb88bea77d702be198da391c Mon Sep 17 00:00:00 2001
From: Andrzej Mateja <mateja.and@gmail.com>
Date: Mon, 7 Feb 2022 22:20:29 +0100
Subject: [PATCH 3/4] More descriptive news entry.

---
 .../next/Library/2021-06-02-19-47-46.bpo-44289.xC5kuV.rst       | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Misc/NEWS.d/next/Library/2021-06-02-19-47-46.bpo-44289.xC5kuV.rst b/Misc/NEWS.d/next/Library/2021-06-02-19-47-46.bpo-44289.xC5kuV.rst
index d2feab9bda49b2..66cca80d509b94 100644
--- a/Misc/NEWS.d/next/Library/2021-06-02-19-47-46.bpo-44289.xC5kuV.rst
+++ b/Misc/NEWS.d/next/Library/2021-06-02-19-47-46.bpo-44289.xC5kuV.rst
@@ -1 +1 @@
-Keep argument file object's current position in tarfile.is_tarifle method.
\ No newline at end of file
+Fix an issue with :meth:`~tarfile.is_tarfile` method when using _fileobj_ argument: position in the _fileobj_ was advanced forward which made it unreadable with :meth:`tarfile.TarFile.open`.

From 628289eb0abecc5fe46f6854e17e5cefd5a8155e Mon Sep 17 00:00:00 2001
From: Andrzej Mateja <mateja.and@gmail.com>
Date: Wed, 9 Feb 2022 05:51:38 +0100
Subject: [PATCH 4/4] bpo-44289: Follow the documentation guidelines for
 parameter names.

---
 .../next/Library/2021-06-02-19-47-46.bpo-44289.xC5kuV.rst       | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Misc/NEWS.d/next/Library/2021-06-02-19-47-46.bpo-44289.xC5kuV.rst b/Misc/NEWS.d/next/Library/2021-06-02-19-47-46.bpo-44289.xC5kuV.rst
index 66cca80d509b94..164138f47ae3bd 100644
--- a/Misc/NEWS.d/next/Library/2021-06-02-19-47-46.bpo-44289.xC5kuV.rst
+++ b/Misc/NEWS.d/next/Library/2021-06-02-19-47-46.bpo-44289.xC5kuV.rst
@@ -1 +1 @@
-Fix an issue with :meth:`~tarfile.is_tarfile` method when using _fileobj_ argument: position in the _fileobj_ was advanced forward which made it unreadable with :meth:`tarfile.TarFile.open`.
+Fix an issue with :meth:`~tarfile.is_tarfile` method when using *fileobj* argument: position in the *fileobj* was advanced forward which made it unreadable with :meth:`tarfile.TarFile.open`.