From c8f182906fddb7c7b90f022ac43f4796ea094ad9 Mon Sep 17 00:00:00 2001
From: Inada Naoki <songofacandy@gmail.com>
Date: Tue, 19 Oct 2021 11:51:48 +0900
Subject: [PATCH] bpo-45475: Revert `__iter__` optimization for GzipFile,
 BZ2File, and LZMAFile. (GH-29016)

This reverts commit d2a8e69c2c605fbaa3656a5f99aa8d295f74c80e.
(cherry picked from commit 0a4c82ddd34a3578684b45b76f49cd289a08740b)

Co-authored-by: Inada Naoki <songofacandy@gmail.com>
---
 Lib/bz2.py                                                    | 4 ----
 Lib/gzip.py                                                   | 4 ----
 Lib/lzma.py                                                   | 4 ----
 .../next/Library/2021-10-18-10-46-47.bpo-45475.sb9KDF.rst     | 4 ++++
 4 files changed, 4 insertions(+), 12 deletions(-)
 create mode 100644 Misc/NEWS.d/next/Library/2021-10-18-10-46-47.bpo-45475.sb9KDF.rst

diff --git a/Lib/bz2.py b/Lib/bz2.py
index 7f1d20632ef139..fabe4f73c8d808 100644
--- a/Lib/bz2.py
+++ b/Lib/bz2.py
@@ -197,10 +197,6 @@ def readline(self, size=-1):
         self._check_can_read()
         return self._buffer.readline(size)
 
-    def __iter__(self):
-        self._check_can_read()
-        return self._buffer.__iter__()
-
     def readlines(self, size=-1):
         """Read a list of lines of uncompressed bytes from the file.
 
diff --git a/Lib/gzip.py b/Lib/gzip.py
index 3d837b744800ed..475ec326c0c982 100644
--- a/Lib/gzip.py
+++ b/Lib/gzip.py
@@ -398,10 +398,6 @@ def readline(self, size=-1):
         self._check_not_closed()
         return self._buffer.readline(size)
 
-    def __iter__(self):
-        self._check_not_closed()
-        return self._buffer.__iter__()
-
 
 class _GzipReader(_compression.DecompressReader):
     def __init__(self, fp):
diff --git a/Lib/lzma.py b/Lib/lzma.py
index 9abf06d91db184..800f52198fbb79 100644
--- a/Lib/lzma.py
+++ b/Lib/lzma.py
@@ -221,10 +221,6 @@ def readline(self, size=-1):
         self._check_can_read()
         return self._buffer.readline(size)
 
-    def __iter__(self):
-        self._check_can_read()
-        return self._buffer.__iter__()
-
     def write(self, data):
         """Write a bytes object to the file.
 
diff --git a/Misc/NEWS.d/next/Library/2021-10-18-10-46-47.bpo-45475.sb9KDF.rst b/Misc/NEWS.d/next/Library/2021-10-18-10-46-47.bpo-45475.sb9KDF.rst
new file mode 100644
index 00000000000000..6fce894e6e4d49
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2021-10-18-10-46-47.bpo-45475.sb9KDF.rst
@@ -0,0 +1,4 @@
+Reverted optimization of iterating :class:`gzip.GzipFile`,
+:class:`bz2.BZ2File`, and :class:`lzma.LZMAFile` (see bpo-43787) because it
+caused regression when user iterate them without having reference of them.
+Patch by Inada Naoki.