Issue #28227: gzip now supports pathlib

Patch by Ethan Furman.

Doc/library/gzip.rst

@@ -56,6 +56,8 @@ The module defines the following items:
    .. versionchanged:: 3.4
       Added support for the ``'x'``, ``'xb'`` and ``'xt'`` modes.
 
+   .. versionchanged:: 3.6
+      Accepts a :term:`path-like object`.
 
 .. class:: GzipFile(filename=None, mode=None, compresslevel=9, fileobj=None, mtime=None)
 
@@ -151,6 +153,9 @@ The module defines the following items:
       The :meth:`~io.BufferedIOBase.read` method now accepts an argument of
       ``None``.
 
+   .. versionchanged:: 3.6
+      Accepts a :term:`path-like object`.
+
 
 .. function:: compress(data, compresslevel=9)
 

Lib/gzip.py

@@ -49,7 +49,7 @@ def open(filename, mode="rb", compresslevel=9,
             raise ValueError("Argument 'newline' not supported in binary mode")
 
     gz_mode = mode.replace("t", "")
-    if isinstance(filename, (str, bytes)):
+    if isinstance(filename, (str, bytes, os.PathLike)):
         binary_file = GzipFile(filename, gz_mode, compresslevel)
     elif hasattr(filename, "read") or hasattr(filename, "write"):
         binary_file = GzipFile(None, gz_mode, compresslevel, filename)
@@ -165,6 +165,8 @@ class GzipFile(_compression.BaseStream):
             filename = getattr(fileobj, 'name', '')
             if not isinstance(filename, (str, bytes)):
                 filename = ''
+        else:
+            filename = os.fspath(filename)
         if mode is None:
             mode = getattr(fileobj, 'mode', 'rb')
 

Lib/test/test_gzip.py

@@ -5,6 +5,7 @@ import unittest
 from test import support
 from test.support import bigmemtest, _4G
 import os
+import pathlib
 import io
 import struct
 import array
@@ -67,6 +68,18 @@ class TestGzip(BaseTest):
         # Test multiple close() calls.
         f.close()
 
+    def test_write_read_with_pathlike_file(self):
+        filename = pathlib.Path(self.filename)
+        with gzip.GzipFile(filename, 'w') as f:
+            f.write(data1 * 50)
+        self.assertIsInstance(f.name, str)
+        with gzip.GzipFile(filename, 'a') as f:
+            f.write(data1)
+        with gzip.GzipFile(filename) as f:
+            d = f.read()
+        self.assertEqual(d, data1 * 51)
+        self.assertIsInstance(f.name, str)
+
     # The following test_write_xy methods test that write accepts
     # the corresponding bytes-like object type as input
     # and that the data written equals bytes(xy) in all cases.
@@ -521,6 +534,15 @@ class TestOpen(BaseTest):
             file_data = gzip.decompress(f.read())
             self.assertEqual(file_data, uncompressed)
 
+    def test_pathlike_file(self):
+        filename = pathlib.Path(self.filename)
+        with gzip.open(filename, "wb") as f:
+            f.write(data1 * 50)
+        with gzip.open(filename, "ab") as f:
+            f.write(data1)
+        with gzip.open(filename) as f:
+            self.assertEqual(f.read(), data1 * 51)
+
     def test_implicit_binary_modes(self):
         # Test implicit binary modes (no "b" or "t" in mode string).
         uncompressed = data1 * 50

Misc/NEWS

@@ -46,6 +46,8 @@ Core and Builtins
 Library
 -------
 
+- Issue #28227: gzip now supports pathlib.  Patch by Ethan Furman.
+
 - Issue #27358: Optimized merging var-keyword arguments and improved error
   message when pass a non-mapping as a var-keyword argument.