From 463b799160924c53b69a3d26f9c39ec10abdadcb Mon Sep 17 00:00:00 2001
From: Ruben Vorderman <r.h.p.vorderman@lumc.nl>
Date: Wed, 5 Jan 2022 12:15:31 +0100
Subject: [PATCH 1/2] Correctly use compresslevel in gzip.compress

---
 Lib/gzip.py                                              | 2 +-
 Lib/test/test_gzip.py                                    | 9 +++++++++
 .../Library/2022-01-18-08-03-19.bpo-46267.vbmuum.rst     | 2 ++
 3 files changed, 12 insertions(+), 1 deletion(-)
 create mode 100644 Misc/NEWS.d/next/Library/2022-01-18-08-03-19.bpo-46267.vbmuum.rst

diff --git a/Lib/gzip.py b/Lib/gzip.py
index 6773ea3eef0971..d0376cd9d608d6 100644
--- a/Lib/gzip.py
+++ b/Lib/gzip.py
@@ -587,7 +587,7 @@ def compress(data, compresslevel=_COMPRESS_LEVEL_BEST, *, mtime=None):
     header = _create_simple_gzip_header(compresslevel, mtime)
     trailer = struct.pack("<LL", zlib.crc32(data), (len(data) & 0xffffffff))
     # Wbits=-15 creates a raw deflate block.
-    return header + zlib.compress(data, wbits=-15) + trailer
+    return header + zlib.compress(data, compresslevel, wbits=-15) + trailer
 
 
 def decompress(data):
diff --git a/Lib/test/test_gzip.py b/Lib/test/test_gzip.py
index aa66d2f07f508c..1e0b7d8d8a691b 100644
--- a/Lib/test/test_gzip.py
+++ b/Lib/test/test_gzip.py
@@ -552,6 +552,15 @@ def test_compress_mtime(self):
                         f.read(1) # to set mtime attribute
                         self.assertEqual(f.mtime, mtime)
 
+    def test_compress_correct_level(self):
+        # gzip.compress calls with mtime == 0 take a different code path.
+        for mtime in (0, 42):
+            with self.subTest(mtime=mtime):
+                nocompress = gzip.compress(data1, compresslevel=0, mtime=mtime)
+                yescompress = gzip.compress(data1, compresslevel=1, mtime=mtime)
+                self.assertIn(data1, nocompress)
+                self.assertNotIn(data1, yescompress)
+
     def test_decompress(self):
         for data in (data1, data2):
             buf = io.BytesIO()
diff --git a/Misc/NEWS.d/next/Library/2022-01-18-08-03-19.bpo-46267.vbmuum.rst b/Misc/NEWS.d/next/Library/2022-01-18-08-03-19.bpo-46267.vbmuum.rst
new file mode 100644
index 00000000000000..a7c0f262aeabae
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2022-01-18-08-03-19.bpo-46267.vbmuum.rst
@@ -0,0 +1,2 @@
+Fix an issue in :func:`gzip.compress` where the compression level was not passed
+through to the underlying :func:`zlib.compress` function.

From 923e24f2e42fe55d18a28c39f95a8aeb2856cef3 Mon Sep 17 00:00:00 2001
From: Jelle Zijlstra <jelle.zijlstra@gmail.com>
Date: Mon, 2 May 2022 21:57:22 -0600
Subject: [PATCH 2/2] Delete NEWS file

This is now a test-only change, so no need for a NEWS entry.
---
 .../next/Library/2022-01-18-08-03-19.bpo-46267.vbmuum.rst       | 2 --
 1 file changed, 2 deletions(-)
 delete mode 100644 Misc/NEWS.d/next/Library/2022-01-18-08-03-19.bpo-46267.vbmuum.rst

diff --git a/Misc/NEWS.d/next/Library/2022-01-18-08-03-19.bpo-46267.vbmuum.rst b/Misc/NEWS.d/next/Library/2022-01-18-08-03-19.bpo-46267.vbmuum.rst
deleted file mode 100644
index a7c0f262aeabae..00000000000000
--- a/Misc/NEWS.d/next/Library/2022-01-18-08-03-19.bpo-46267.vbmuum.rst
+++ /dev/null
@@ -1,2 +0,0 @@
-Fix an issue in :func:`gzip.compress` where the compression level was not passed
-through to the underlying :func:`zlib.compress` function.