Issue #28225: bz2 module now supports pathlib

Initial patch by Ethan Furman.

Doc/library/bz2.rst

@@ -61,6 +61,9 @@ All of the classes in this module may safely be accessed from multiple threads.
    .. versionchanged:: 3.4
       The ``'x'`` (exclusive creation) mode was added.
 
+   .. versionchanged:: 3.6
+      Accepts a :term:`path-like object`.
+
 
 .. class:: BZ2File(filename, mode='r', buffering=None, compresslevel=9)
 
@@ -128,6 +131,9 @@ All of the classes in this module may safely be accessed from multiple threads.
       The :meth:`~io.BufferedIOBase.read` method now accepts an argument of
       ``None``.
 
+   .. versionchanged:: 3.6
+      Accepts a :term:`path-like object`.
+
 
 Incremental (de)compression
 ---------------------------

Lib/bz2.py

@@ -11,6 +11,7 @@ __author__ = "Nadeem Vawda <nadeem.vawda@gmail.com>"
 
 from builtins import open as _builtin_open
 import io
+import os
 import warnings
 import _compression
 
@@ -42,9 +43,9 @@ class BZ2File(_compression.BaseStream):
     def __init__(self, filename, mode="r", buffering=None, compresslevel=9):
         """Open a bzip2-compressed file.
 
-        If filename is a str or bytes object, it gives the name
-        of the file to be opened. Otherwise, it should be a file object,
-        which will be used to read or write the compressed data.
+        If filename is a str, bytes, or PathLike object, it gives the
+        name of the file to be opened. Otherwise, it should be a file
+        object, which will be used to read or write the compressed data.
 
         mode can be 'r' for reading (default), 'w' for (over)writing,
         'x' for creating exclusively, or 'a' for appending. These can
@@ -91,7 +92,7 @@ class BZ2File(_compression.BaseStream):
         else:
             raise ValueError("Invalid mode: %r" % (mode,))
 
-        if isinstance(filename, (str, bytes)):
+        if isinstance(filename, (str, bytes, os.PathLike)):
             self._fp = _builtin_open(filename, mode)
             self._closefp = True
             self._mode = mode_code
@@ -99,7 +100,7 @@ class BZ2File(_compression.BaseStream):
             self._fp = filename
             self._mode = mode_code
         else:
-            raise TypeError("filename must be a str or bytes object, or a file")
+            raise TypeError("filename must be a str, bytes, file or PathLike object")
 
         if self._mode == _MODE_READ:
             raw = _compression.DecompressReader(self._fp,
@@ -289,8 +290,9 @@ def open(filename, mode="rb", compresslevel=9,
          encoding=None, errors=None, newline=None):
     """Open a bzip2-compressed file in binary or text mode.
 
-    The filename argument can be an actual filename (a str or bytes
-    object), or an existing file object to read from or write to.
+    The filename argument can be an actual filename (a str, bytes, or
+    PathLike object), or an existing file object to read from or write
+    to.
 
     The mode argument can be "r", "rb", "w", "wb", "x", "xb", "a" or
     "ab" for binary mode, or "rt", "wt", "xt" or "at" for text mode.

Lib/test/test_bz2.py

@@ -6,6 +6,7 @@ from io import BytesIO, DEFAULT_BUFFER_SIZE
 import os
 import pickle
 import glob
+import pathlib
 import random
 import subprocess
 import sys
@@ -560,6 +561,13 @@ class BZ2FileTest(BaseTest):
         with BZ2File(str_filename, "rb") as f:
             self.assertEqual(f.read(), self.DATA)
 
+    def testOpenPathLikeFilename(self):
+        filename = pathlib.Path(self.filename)
+        with BZ2File(filename, "wb") as f:
+            f.write(self.DATA)
+        with BZ2File(filename, "rb") as f:
+            self.assertEqual(f.read(), self.DATA)
+
     def testDecompressLimited(self):
         """Decompressed data buffering should be limited"""
         bomb = bz2.compress(b'\0' * int(2e6), compresslevel=9)

Misc/NEWS

@@ -46,6 +46,8 @@ Core and Builtins
 Library
 -------
 
+- Issue #28225: bz2 module now supports pathlib.  Initial patch by Ethan Furman.
+
 - Issue #28227: gzip now supports pathlib.  Patch by Ethan Furman.
 
 - Issue #27358: Optimized merging var-keyword arguments and improved error