Simplify usage of LZMAFile's fileobj support, like with BZ2File.

5 files changed, 133 insertions, 143 deletions

diff --git a/Doc/library/lzma.rst b/Doc/library/lzma.rst
index 33a542883a..156d77aec0 100644
--- a/Doc/library/lzma.rst
+++ b/Doc/library/lzma.rst
@@ -29,18 +29,20 @@ from multiple threads, it is necessary to protect it with a lock.
 Reading and writing compressed files
 ------------------------------------
 
-.. class:: LZMAFile(filename=None, mode="r", \*, fileobj=None, format=None, check=-1, preset=None, filters=None)
+.. class:: LZMAFile(filename=None, mode="r", \*, format=None, check=-1, preset=None, filters=None)
 
-   Open an LZMA-compressed file.
+   Open an LZMA-compressed file in binary mode.
 
-   An :class:`LZMAFile` can wrap an existing :term:`file object` (given by
-   *fileobj*), or operate directly on a named file (named by *filename*).
-   Exactly one of these two parameters should be provided. If *fileobj* is
-   provided, it is not closed when the :class:`LZMAFile` is closed.
+   An :class:`LZMAFile` can wrap an already-open :term:`file object`, or operate
+   directly on a named file. The *filename* argument specifies either the file
+   object to wrap, or the name of the file to open (as a :class:`str` or
+   :class:`bytes` object). When wrapping an existing file object, the wrapped
+   file will not be closed when the :class:`LZMAFile` is closed.
 
    The *mode* argument can be either ``"r"`` for reading (default), ``"w"`` for
-   overwriting, or ``"a"`` for appending. If *fileobj* is provided, a mode of
-   ``"w"`` does not truncate the file, and is instead equivalent to ``"a"``.
+   overwriting, or ``"a"`` for appending. If *filename* is an existing file
+   object, a mode of ``"w"`` does not truncate the file, and is instead
+   equivalent to ``"a"``.
 
    When opening a file for reading, the input file may be the concatenation of
    multiple separate compressed streams. These are transparently decoded as a
@@ -360,7 +362,7 @@ Writing compressed data to an already-open file::
    import lzma
    with open("file.xz", "wb") as f:
        f.write(b"This data will not be compressed\n")
-       with lzma.LZMAFile(fileobj=f, mode="w") as lzf:
+       with lzma.LZMAFile(f, "w") as lzf:
            lzf.write(b"This *will* be compressed\n")
        f.write(b"Not compressed\n")
 
diff --git a/Lib/lzma.py b/Lib/lzma.py
index 1c101f72f9..8fb3f03328 100644
--- a/Lib/lzma.py
+++ b/Lib/lzma.py
@@ -46,13 +46,12 @@ class LZMAFile(io.BufferedIOBase):
     """
 
     def __init__(self, filename=None, mode="r", *,
-                 fileobj=None, format=None, check=-1,
-                 preset=None, filters=None):
-        """Open an LZMA-compressed file.
+                 format=None, check=-1, preset=None, filters=None):
+        """Open an LZMA-compressed file in binary mode.
 
-        If filename is given, open the named file. Otherwise, operate on
-        the file object given by fileobj. Exactly one of these two
-        parameters should be provided.
+        filename can be either an actual file name (given as a str or
+        bytes object), in which case the named file is opened, or it can
+        be an existing file object to read from or write to.
 
         mode can be "r" for reading (default), "w" for (over)writing, or
         "a" for appending.
@@ -119,16 +118,16 @@ class LZMAFile(io.BufferedIOBase):
         else:
             raise ValueError("Invalid mode: {!r}".format(mode))
 
-        if filename is not None and fileobj is None:
+        if isinstance(filename, (str, bytes)):
             mode += "b"
             self._fp = open(filename, mode)
             self._closefp = True
             self._mode = mode_code
-        elif fileobj is not None and filename is None:
-            self._fp = fileobj
+        elif hasattr(filename, "read") or hasattr(filename, "write"):
+            self._fp = filename
             self._mode = mode_code
         else:
-            raise ValueError("Must give exactly one of filename and fileobj")
+            raise TypeError("filename must be a str or bytes object, or a file")
 
     def close(self):
         """Flush and close the file.
diff --git a/Lib/tarfile.py b/Lib/tarfile.py
index 6d735699fc..7b9f407dd4 100644
--- a/Lib/tarfile.py
+++ b/Lib/tarfile.py
@@ -1681,8 +1681,7 @@ class TarFile(object):
         except ImportError:
             raise CompressionError("lzma module is not available")
 
-        fileobj = lzma.LZMAFile(filename=name if fileobj is None else None,
-                mode=mode, fileobj=fileobj, preset=preset)
+        fileobj = lzma.LZMAFile(fileobj or name, mode, preset=preset)
 
         try:
             t = cls.taropen(name, mode, fileobj, **kwargs)
diff --git a/Lib/test/test_lzma.py b/Lib/test/test_lzma.py
index 97523c13f2..aee7921ca4 100644
--- a/Lib/test/test_lzma.py
+++ b/Lib/test/test_lzma.py
@@ -358,11 +358,11 @@ class TempFile:
 class FileTestCase(unittest.TestCase):
 
     def test_init(self):
-        with LZMAFile(fileobj=BytesIO(COMPRESSED_XZ)) as f:
+        with LZMAFile(BytesIO(COMPRESSED_XZ)) as f:
             pass
-        with LZMAFile(fileobj=BytesIO(), mode="w") as f:
+        with LZMAFile(BytesIO(), "w") as f:
             pass
-        with LZMAFile(fileobj=BytesIO(), mode="a") as f:
+        with LZMAFile(BytesIO(), "a") as f:
             pass
 
     def test_init_with_filename(self):
@@ -376,88 +376,84 @@ class FileTestCase(unittest.TestCase):
 
     def test_init_bad_mode(self):
         with self.assertRaises(ValueError):
-            LZMAFile(fileobj=BytesIO(COMPRESSED_XZ), mode=(3, "x"))
+            LZMAFile(BytesIO(COMPRESSED_XZ), (3, "x"))
         with self.assertRaises(ValueError):
-            LZMAFile(fileobj=BytesIO(COMPRESSED_XZ), mode="")
+            LZMAFile(BytesIO(COMPRESSED_XZ), "")
         with self.assertRaises(ValueError):
-            LZMAFile(fileobj=BytesIO(COMPRESSED_XZ), mode="x")
+            LZMAFile(BytesIO(COMPRESSED_XZ), "x")
         with self.assertRaises(ValueError):
-            LZMAFile(fileobj=BytesIO(COMPRESSED_XZ), mode="rb")
+            LZMAFile(BytesIO(COMPRESSED_XZ), "rb")
         with self.assertRaises(ValueError):
-            LZMAFile(fileobj=BytesIO(COMPRESSED_XZ), mode="r+")
+            LZMAFile(BytesIO(COMPRESSED_XZ), "r+")
         with self.assertRaises(ValueError):
-            LZMAFile(fileobj=BytesIO(COMPRESSED_XZ), mode="wb")
+            LZMAFile(BytesIO(COMPRESSED_XZ), "wb")
         with self.assertRaises(ValueError):
-            LZMAFile(fileobj=BytesIO(COMPRESSED_XZ), mode="w+")
+            LZMAFile(BytesIO(COMPRESSED_XZ), "w+")
         with self.assertRaises(ValueError):
-            LZMAFile(fileobj=BytesIO(COMPRESSED_XZ), mode="rw")
+            LZMAFile(BytesIO(COMPRESSED_XZ), "rw")
 
     def test_init_bad_check(self):
         with self.assertRaises(TypeError):
-            LZMAFile(fileobj=BytesIO(), mode="w", check=b"asd")
+            LZMAFile(BytesIO(), "w", check=b"asd")
         # CHECK_UNKNOWN and anything above CHECK_ID_MAX should be invalid.
         with self.assertRaises(LZMAError):
-            LZMAFile(fileobj=BytesIO(), mode="w", check=lzma.CHECK_UNKNOWN)
+            LZMAFile(BytesIO(), "w", check=lzma.CHECK_UNKNOWN)
         with self.assertRaises(LZMAError):
-            LZMAFile(fileobj=BytesIO(), mode="w", check=lzma.CHECK_ID_MAX + 3)
+            LZMAFile(BytesIO(), "w", check=lzma.CHECK_ID_MAX + 3)
         # Cannot specify a check with mode="r".
         with self.assertRaises(ValueError):
-            LZMAFile(fileobj=BytesIO(COMPRESSED_XZ), check=lzma.CHECK_NONE)
+            LZMAFile(BytesIO(COMPRESSED_XZ), check=lzma.CHECK_NONE)
         with self.assertRaises(ValueError):
-            LZMAFile(fileobj=BytesIO(COMPRESSED_XZ), check=lzma.CHECK_CRC32)
+            LZMAFile(BytesIO(COMPRESSED_XZ), check=lzma.CHECK_CRC32)
         with self.assertRaises(ValueError):
-            LZMAFile(fileobj=BytesIO(COMPRESSED_XZ), check=lzma.CHECK_CRC64)
+            LZMAFile(BytesIO(COMPRESSED_XZ), check=lzma.CHECK_CRC64)
         with self.assertRaises(ValueError):
-            LZMAFile(fileobj=BytesIO(COMPRESSED_XZ), check=lzma.CHECK_SHA256)
+            LZMAFile(BytesIO(COMPRESSED_XZ), check=lzma.CHECK_SHA256)
         with self.assertRaises(ValueError):
-            LZMAFile(fileobj=BytesIO(COMPRESSED_XZ), check=lzma.CHECK_UNKNOWN)
+            LZMAFile(BytesIO(COMPRESSED_XZ), check=lzma.CHECK_UNKNOWN)
 
     def test_init_bad_preset(self):
         with self.assertRaises(TypeError):
-            LZMAFile(fileobj=BytesIO(), mode="w", preset=4.39)
+            LZMAFile(BytesIO(), "w", preset=4.39)
         with self.assertRaises(LZMAError):
-            LZMAFile(fileobj=BytesIO(), mode="w", preset=10)
+            LZMAFile(BytesIO(), "w", preset=10)
         with self.assertRaises(LZMAError):
-            LZMAFile(fileobj=BytesIO(), mode="w", preset=23)
+            LZMAFile(BytesIO(), "w", preset=23)
         with self.assertRaises(OverflowError):
-            LZMAFile(fileobj=BytesIO(), mode="w", preset=-1)
+            LZMAFile(BytesIO(), "w", preset=-1)
         with self.assertRaises(OverflowError):
-            LZMAFile(fileobj=BytesIO(), mode="w", preset=-7)
+            LZMAFile(BytesIO(), "w", preset=-7)
         with self.assertRaises(TypeError):
-            LZMAFile(fileobj=BytesIO(), mode="w", preset="foo")
+            LZMAFile(BytesIO(), "w", preset="foo")
         # Cannot specify a preset with mode="r".
         with self.assertRaises(ValueError):
-            LZMAFile(fileobj=BytesIO(COMPRESSED_XZ), preset=3)
+            LZMAFile(BytesIO(COMPRESSED_XZ), preset=3)
 
     def test_init_bad_filter_spec(self):
         with self.assertRaises(TypeError):
-            LZMAFile(fileobj=BytesIO(), mode="w", filters=[b"wobsite"])
+            LZMAFile(BytesIO(), "w", filters=[b"wobsite"])
         with self.assertRaises(ValueError):
-            LZMAFile(fileobj=BytesIO(), mode="w", filters=[{"xyzzy": 3}])
+            LZMAFile(BytesIO(), "w", filters=[{"xyzzy": 3}])
         with self.assertRaises(ValueError):
-            LZMAFile(fileobj=BytesIO(), mode="w", filters=[{"id": 98765}])
+            LZMAFile(BytesIO(), "w", filters=[{"id": 98765}])
         with self.assertRaises(ValueError):
-            LZMAFile(fileobj=BytesIO(), mode="w",
+            LZMAFile(BytesIO(), "w",
                      filters=[{"id": lzma.FILTER_LZMA2, "foo": 0}])
         with self.assertRaises(ValueError):
-            LZMAFile(fileobj=BytesIO(), mode="w",
+            LZMAFile(BytesIO(), "w",
                      filters=[{"id": lzma.FILTER_DELTA, "foo": 0}])
         with self.assertRaises(ValueError):
-            LZMAFile(fileobj=BytesIO(), mode="w",
+            LZMAFile(BytesIO(), "w",
                      filters=[{"id": lzma.FILTER_X86, "foo": 0}])
 
     def test_init_with_preset_and_filters(self):
         with self.assertRaises(ValueError):
-            LZMAFile(fileobj=BytesIO(), mode="w", format=lzma.FORMAT_RAW,
-                     preset=6,  filters=FILTERS_RAW_1)
-
-    def test_init_with_filename_and_fileobj(self):
-        with self.assertRaises(ValueError):
-            LZMAFile("/dev/null", fileobj=BytesIO())
+            LZMAFile(BytesIO(), "w", format=lzma.FORMAT_RAW,
+                     preset=6, filters=FILTERS_RAW_1)
 
     def test_close(self):
         with BytesIO(COMPRESSED_XZ) as src:
-            f = LZMAFile(fileobj=src)
+            f = LZMAFile(src)
             f.close()
             # LZMAFile.close() should not close the underlying file object.
             self.assertFalse(src.closed)
@@ -476,7 +472,7 @@ class FileTestCase(unittest.TestCase):
             f.close()
 
     def test_closed(self):
-        f = LZMAFile(fileobj=BytesIO(COMPRESSED_XZ))
+        f = LZMAFile(BytesIO(COMPRESSED_XZ))
         try:
             self.assertFalse(f.closed)
             f.read()
@@ -485,7 +481,7 @@ class FileTestCase(unittest.TestCase):
             f.close()
         self.assertTrue(f.closed)
 
-        f = LZMAFile(fileobj=BytesIO(), mode="w")
+        f = LZMAFile(BytesIO(), "w")
         try:
             self.assertFalse(f.closed)
         finally:
@@ -493,7 +489,7 @@ class FileTestCase(unittest.TestCase):
         self.assertTrue(f.closed)
 
     def test_fileno(self):
-        f = LZMAFile(fileobj=BytesIO(COMPRESSED_XZ))
+        f = LZMAFile(BytesIO(COMPRESSED_XZ))
         try:
             self.assertRaises(UnsupportedOperation, f.fileno)
         finally:
@@ -509,7 +505,7 @@ class FileTestCase(unittest.TestCase):
         self.assertRaises(ValueError, f.fileno)
 
     def test_seekable(self):
-        f = LZMAFile(fileobj=BytesIO(COMPRESSED_XZ))
+        f = LZMAFile(BytesIO(COMPRESSED_XZ))
         try:
             self.assertTrue(f.seekable())
             f.read()
@@ -518,7 +514,7 @@ class FileTestCase(unittest.TestCase):
             f.close()
         self.assertRaises(ValueError, f.seekable)
 
-        f = LZMAFile(fileobj=BytesIO(), mode="w")
+        f = LZMAFile(BytesIO(), "w")
         try:
             self.assertFalse(f.seekable())
         finally:
@@ -527,7 +523,7 @@ class FileTestCase(unittest.TestCase):
 
         src = BytesIO(COMPRESSED_XZ)
         src.seekable = lambda: False
-        f = LZMAFile(fileobj=src)
+        f = LZMAFile(src)
         try:
             self.assertFalse(f.seekable())
         finally:
@@ -535,7 +531,7 @@ class FileTestCase(unittest.TestCase):
         self.assertRaises(ValueError, f.seekable)
 
     def test_readable(self):
-        f = LZMAFile(fileobj=BytesIO(COMPRESSED_XZ))
+        f = LZMAFile(BytesIO(COMPRESSED_XZ))
         try:
             self.assertTrue(f.readable())
             f.read()
@@ -544,7 +540,7 @@ class FileTestCase(unittest.TestCase):
             f.close()
         self.assertRaises(ValueError, f.readable)
 
-        f = LZMAFile(fileobj=BytesIO(), mode="w")
+        f = LZMAFile(BytesIO(), "w")
         try:
             self.assertFalse(f.readable())
         finally:
@@ -552,7 +548,7 @@ class FileTestCase(unittest.TestCase):
         self.assertRaises(ValueError, f.readable)
 
     def test_writable(self):
-        f = LZMAFile(fileobj=BytesIO(COMPRESSED_XZ))
+        f = LZMAFile(BytesIO(COMPRESSED_XZ))
         try:
             self.assertFalse(f.writable())
             f.read()
@@ -561,7 +557,7 @@ class FileTestCase(unittest.TestCase):
             f.close()
         self.assertRaises(ValueError, f.writable)
 
-        f = LZMAFile(fileobj=BytesIO(), mode="w")
+        f = LZMAFile(BytesIO(), "w")
         try:
             self.assertTrue(f.writable())
         finally:
@@ -569,50 +565,46 @@ class FileTestCase(unittest.TestCase):
         self.assertRaises(ValueError, f.writable)
 
     def test_read(self):
-        with LZMAFile(fileobj=BytesIO(COMPRESSED_XZ)) as f:
+        with LZMAFile(BytesIO(COMPRESSED_XZ)) as f:
             self.assertEqual(f.read(), INPUT)
             self.assertEqual(f.read(), b"")
-        with LZMAFile(fileobj=BytesIO(COMPRESSED_ALONE)) as f:
+        with LZMAFile(BytesIO(COMPRESSED_ALONE)) as f:
             self.assertEqual(f.read(), INPUT)
-        with LZMAFile(fileobj=BytesIO(COMPRESSED_XZ),
-                      format=lzma.FORMAT_XZ) as f:
+        with LZMAFile(BytesIO(COMPRESSED_XZ), format=lzma.FORMAT_XZ) as f:
             self.assertEqual(f.read(), INPUT)
             self.assertEqual(f.read(), b"")
-        with LZMAFile(fileobj=BytesIO(COMPRESSED_ALONE),
-                      format=lzma.FORMAT_ALONE) as f:
+        with LZMAFile(BytesIO(COMPRESSED_ALONE), format=lzma.FORMAT_ALONE) as f:
             self.assertEqual(f.read(), INPUT)
             self.assertEqual(f.read(), b"")
-        with LZMAFile(fileobj=BytesIO(COMPRESSED_RAW_1),
+        with LZMAFile(BytesIO(COMPRESSED_RAW_1),
                       format=lzma.FORMAT_RAW, filters=FILTERS_RAW_1) as f:
             self.assertEqual(f.read(), INPUT)
             self.assertEqual(f.read(), b"")
-        with LZMAFile(fileobj=BytesIO(COMPRESSED_RAW_2),
+        with LZMAFile(BytesIO(COMPRESSED_RAW_2),
                       format=lzma.FORMAT_RAW, filters=FILTERS_RAW_2) as f:
             self.assertEqual(f.read(), INPUT)
             self.assertEqual(f.read(), b"")
-        with LZMAFile(fileobj=BytesIO(COMPRESSED_RAW_3),
+        with LZMAFile(BytesIO(COMPRESSED_RAW_3),
                       format=lzma.FORMAT_RAW, filters=FILTERS_RAW_3) as f:
             self.assertEqual(f.read(), INPUT)
             self.assertEqual(f.read(), b"")
-        with LZMAFile(fileobj=BytesIO(COMPRESSED_RAW_4),
+        with LZMAFile(BytesIO(COMPRESSED_RAW_4),
                       format=lzma.FORMAT_RAW, filters=FILTERS_RAW_4) as f:
             self.assertEqual(f.read(), INPUT)
             self.assertEqual(f.read(), b"")
 
     def test_read_0(self):
-        with LZMAFile(fileobj=BytesIO(COMPRESSED_XZ)) as f:
+        with LZMAFile(BytesIO(COMPRESSED_XZ)) as f:
             self.assertEqual(f.read(0), b"")
-        with LZMAFile(fileobj=BytesIO(COMPRESSED_ALONE)) as f:
+        with LZMAFile(BytesIO(COMPRESSED_ALONE)) as f:
             self.assertEqual(f.read(0), b"")
-        with LZMAFile(fileobj=BytesIO(COMPRESSED_XZ),
-                      format=lzma.FORMAT_XZ) as f:
+        with LZMAFile(BytesIO(COMPRESSED_XZ), format=lzma.FORMAT_XZ) as f:
             self.assertEqual(f.read(0), b"")
-        with LZMAFile(fileobj=BytesIO(COMPRESSED_ALONE),
-                      format=lzma.FORMAT_ALONE) as f:
+        with LZMAFile(BytesIO(COMPRESSED_ALONE), format=lzma.FORMAT_ALONE) as f:
             self.assertEqual(f.read(0), b"")
 
     def test_read_10(self):
-        with LZMAFile(fileobj=BytesIO(COMPRESSED_XZ)) as f:
+        with LZMAFile(BytesIO(COMPRESSED_XZ)) as f:
             chunks = []
             while True:
                 result = f.read(10)
@@ -623,11 +615,11 @@ class FileTestCase(unittest.TestCase):
             self.assertEqual(b"".join(chunks), INPUT)
 
     def test_read_multistream(self):
-        with LZMAFile(fileobj=BytesIO(COMPRESSED_XZ * 5)) as f:
+        with LZMAFile(BytesIO(COMPRESSED_XZ * 5)) as f:
             self.assertEqual(f.read(), INPUT * 5)
-        with LZMAFile(fileobj=BytesIO(COMPRESSED_XZ + COMPRESSED_ALONE)) as f:
+        with LZMAFile(BytesIO(COMPRESSED_XZ + COMPRESSED_ALONE)) as f:
             self.assertEqual(f.read(), INPUT * 2)
-        with LZMAFile(fileobj=BytesIO(COMPRESSED_RAW_3 * 4),
+        with LZMAFile(BytesIO(COMPRESSED_RAW_3 * 4),
                       format=lzma.FORMAT_RAW, filters=FILTERS_RAW_3) as f:
             self.assertEqual(f.read(), INPUT * 4)
 
@@ -637,7 +629,7 @@ class FileTestCase(unittest.TestCase):
         saved_buffer_size = lzma._BUFFER_SIZE
         lzma._BUFFER_SIZE = len(COMPRESSED_XZ)
         try:
-            with LZMAFile(fileobj=BytesIO(COMPRESSED_XZ *  5)) as f:
+            with LZMAFile(BytesIO(COMPRESSED_XZ *  5)) as f:
                 self.assertEqual(f.read(), INPUT * 5)
         finally:
             lzma._BUFFER_SIZE = saved_buffer_size
@@ -649,20 +641,20 @@ class FileTestCase(unittest.TestCase):
                 self.assertEqual(f.read(), b"")
 
     def test_read_incomplete(self):
-        with LZMAFile(fileobj=BytesIO(COMPRESSED_XZ[:128])) as f:
+        with LZMAFile(BytesIO(COMPRESSED_XZ[:128])) as f:
             self.assertRaises(EOFError, f.read)
 
     def test_read_bad_args(self):
-        f = LZMAFile(fileobj=BytesIO(COMPRESSED_XZ))
+        f = LZMAFile(BytesIO(COMPRESSED_XZ))
         f.close()
         self.assertRaises(ValueError, f.read)
-        with LZMAFile(fileobj=BytesIO(), mode="w") as f:
+        with LZMAFile(BytesIO(), "w") as f:
             self.assertRaises(ValueError, f.read)
-        with LZMAFile(fileobj=BytesIO(COMPRESSED_XZ)) as f:
+        with LZMAFile(BytesIO(COMPRESSED_XZ)) as f:
             self.assertRaises(TypeError, f.read, None)
 
     def test_read1(self):
-        with LZMAFile(fileobj=BytesIO(COMPRESSED_XZ)) as f:
+        with LZMAFile(BytesIO(COMPRESSED_XZ)) as f:
             blocks = []
             while True:
                 result = f.read1()
@@ -673,11 +665,11 @@ class FileTestCase(unittest.TestCase):
             self.assertEqual(f.read1(), b"")
 
     def test_read1_0(self):
-        with LZMAFile(fileobj=BytesIO(COMPRESSED_XZ)) as f:
+        with LZMAFile(BytesIO(COMPRESSED_XZ)) as f:
             self.assertEqual(f.read1(0), b"")
 
     def test_read1_10(self):
-        with LZMAFile(fileobj=BytesIO(COMPRESSED_XZ)) as f:
+        with LZMAFile(BytesIO(COMPRESSED_XZ)) as f:
             blocks = []
             while True:
                 result = f.read1(10)
@@ -688,7 +680,7 @@ class FileTestCase(unittest.TestCase):
             self.assertEqual(f.read1(), b"")
 
     def test_read1_multistream(self):
-        with LZMAFile(fileobj=BytesIO(COMPRESSED_XZ * 5)) as f:
+        with LZMAFile(BytesIO(COMPRESSED_XZ * 5)) as f:
             blocks = []
             while True:
                 result = f.read1()
@@ -699,78 +691,76 @@ class FileTestCase(unittest.TestCase):
             self.assertEqual(f.read1(), b"")
 
     def test_read1_bad_args(self):
-        f = LZMAFile(fileobj=BytesIO(COMPRESSED_XZ))
+        f = LZMAFile(BytesIO(COMPRESSED_XZ))
         f.close()
         self.assertRaises(ValueError, f.read1)
-        with LZMAFile(fileobj=BytesIO(), mode="w") as f:
+        with LZMAFile(BytesIO(), "w") as f:
             self.assertRaises(ValueError, f.read1)
-        with LZMAFile(fileobj=BytesIO(COMPRESSED_XZ)) as f:
+        with LZMAFile(BytesIO(COMPRESSED_XZ)) as f:
             self.assertRaises(TypeError, f.read1, None)
 
     def test_peek(self):
-        with LZMAFile(fileobj=BytesIO(COMPRESSED_XZ)) as f:
+        with LZMAFile(BytesIO(COMPRESSED_XZ)) as f:
             result = f.peek()
             self.assertGreater(len(result), 0)
             self.assertTrue(INPUT.startswith(result))
             self.assertEqual(f.read(), INPUT)
-        with LZMAFile(fileobj=BytesIO(COMPRESSED_XZ)) as f:
+        with LZMAFile(BytesIO(COMPRESSED_XZ)) as f:
             result = f.peek(10)
             self.assertGreater(len(result), 0)
             self.assertTrue(INPUT.startswith(result))
             self.assertEqual(f.read(), INPUT)
 
     def test_peek_bad_args(self):
-        with LZMAFile(fileobj=BytesIO(), mode="w") as f:
+        with LZMAFile(BytesIO(), "w") as f:
             self.assertRaises(ValueError, f.peek)
 
     def test_iterator(self):
         with BytesIO(INPUT) as f:
             lines = f.readlines()
-        with LZMAFile(fileobj=BytesIO(COMPRESSED_XZ)) as f:
+        with LZMAFile(BytesIO(COMPRESSED_XZ)) as f:
             self.assertListEqual(list(iter(f)), lines)
-        with LZMAFile(fileobj=BytesIO(COMPRESSED_ALONE)) as f:
+        with LZMAFile(BytesIO(COMPRESSED_ALONE)) as f:
             self.assertListEqual(list(iter(f)), lines)
-        with LZMAFile(fileobj=BytesIO(COMPRESSED_XZ),
-                      format=lzma.FORMAT_XZ) as f:
+        with LZMAFile(BytesIO(COMPRESSED_XZ), format=lzma.FORMAT_XZ) as f:
             self.assertListEqual(list(iter(f)), lines)
-        with LZMAFile(fileobj=BytesIO(COMPRESSED_ALONE),
-                      format=lzma.FORMAT_ALONE) as f:
+        with LZMAFile(BytesIO(COMPRESSED_ALONE), format=lzma.FORMAT_ALONE) as f:
             self.assertListEqual(list(iter(f)), lines)
-        with LZMAFile(fileobj=BytesIO(COMPRESSED_RAW_2),
+        with LZMAFile(BytesIO(COMPRESSED_RAW_2),
                       format=lzma.FORMAT_RAW, filters=FILTERS_RAW_2) as f:
             self.assertListEqual(list(iter(f)), lines)
 
     def test_readline(self):
         with BytesIO(INPUT) as f:
             lines = f.readlines()
-        with LZMAFile(fileobj=BytesIO(COMPRESSED_XZ)) as f:
+        with LZMAFile(BytesIO(COMPRESSED_XZ)) as f:
             for line in lines:
                 self.assertEqual(f.readline(), line)
 
     def test_readlines(self):
         with BytesIO(INPUT) as f:
             lines = f.readlines()
-        with LZMAFile(fileobj=BytesIO(COMPRESSED_XZ)) as f:
+        with LZMAFile(BytesIO(COMPRESSED_XZ)) as f:
             self.assertListEqual(f.readlines(), lines)
 
     def test_write(self):
         with BytesIO() as dst:
-            with LZMAFile(fileobj=dst, mode="w") as f:
+            with LZMAFile(dst, "w") as f:
                 f.write(INPUT)
             expected = lzma.compress(INPUT)
             self.assertEqual(dst.getvalue(), expected)
         with BytesIO() as dst:
-            with LZMAFile(fileobj=dst, mode="w", format=lzma.FORMAT_XZ) as f:
+            with LZMAFile(dst, "w", format=lzma.FORMAT_XZ) as f:
                 f.write(INPUT)
             expected = lzma.compress(INPUT, format=lzma.FORMAT_XZ)
             self.assertEqual(dst.getvalue(), expected)
         with BytesIO() as dst:
-            with LZMAFile(fileobj=dst, mode="w", format=lzma.FORMAT_ALONE) as f:
+            with LZMAFile(dst, "w", format=lzma.FORMAT_ALONE) as f:
                 f.write(INPUT)
             expected = lzma.compress(INPUT, format=lzma.FORMAT_ALONE)
             self.assertEqual(dst.getvalue(), expected)
         with BytesIO() as dst:
-            with LZMAFile(fileobj=dst, mode="w", format=lzma.FORMAT_RAW,
+            with LZMAFile(dst, "w", format=lzma.FORMAT_RAW,
                           filters=FILTERS_RAW_2) as f:
                 f.write(INPUT)
             expected = lzma.compress(INPUT, format=lzma.FORMAT_RAW,
@@ -779,7 +769,7 @@ class FileTestCase(unittest.TestCase):
 
     def test_write_10(self):
         with BytesIO() as dst:
-            with LZMAFile(fileobj=dst, mode="w") as f:
+            with LZMAFile(dst, "w") as f:
                 for start in range(0, len(INPUT), 10):
                     f.write(INPUT[start:start+10])
             expected = lzma.compress(INPUT)
@@ -791,11 +781,11 @@ class FileTestCase(unittest.TestCase):
         part3 = INPUT[1536:]
         expected = b"".join(lzma.compress(x) for x in (part1, part2, part3))
         with BytesIO() as dst:
-            with LZMAFile(fileobj=dst, mode="w") as f:
+            with LZMAFile(dst, "w") as f:
                 f.write(part1)
-            with LZMAFile(fileobj=dst, mode="a") as f:
+            with LZMAFile(dst, "a") as f:
                 f.write(part2)
-            with LZMAFile(fileobj=dst, mode="a") as f:
+            with LZMAFile(dst, "a") as f:
                 f.write(part3)
             self.assertEqual(dst.getvalue(), expected)
 
@@ -827,12 +817,12 @@ class FileTestCase(unittest.TestCase):
             unlink(TESTFN)
 
     def test_write_bad_args(self):
-        f = LZMAFile(fileobj=BytesIO(), mode="w")
+        f = LZMAFile(BytesIO(), "w")
         f.close()
         self.assertRaises(ValueError, f.write, b"foo")
-        with LZMAFile(fileobj=BytesIO(COMPRESSED_XZ), mode="r") as f:
+        with LZMAFile(BytesIO(COMPRESSED_XZ), "r") as f:
             self.assertRaises(ValueError, f.write, b"bar")
-        with LZMAFile(fileobj=BytesIO(), mode="w") as f:
+        with LZMAFile(BytesIO(), "w") as f:
             self.assertRaises(TypeError, f.write, None)
             self.assertRaises(TypeError, f.write, "text")
             self.assertRaises(TypeError, f.write, 789)
@@ -841,75 +831,75 @@ class FileTestCase(unittest.TestCase):
         with BytesIO(INPUT) as f:
             lines = f.readlines()
         with BytesIO() as dst:
-            with LZMAFile(fileobj=dst, mode="w") as f:
+            with LZMAFile(dst, "w") as f:
                 f.writelines(lines)
             expected = lzma.compress(INPUT)
             self.assertEqual(dst.getvalue(), expected)
 
     def test_seek_forward(self):
-        with LZMAFile(fileobj=BytesIO(COMPRESSED_XZ)) as f:
+        with LZMAFile(BytesIO(COMPRESSED_XZ)) as f:
             f.seek(555)
             self.assertEqual(f.read(), INPUT[555:])
 
     def test_seek_forward_across_streams(self):
-        with LZMAFile(fileobj=BytesIO(COMPRESSED_XZ * 2)) as f:
+        with LZMAFile(BytesIO(COMPRESSED_XZ * 2)) as f:
             f.seek(len(INPUT) + 123)
             self.assertEqual(f.read(), INPUT[123:])
 
     def test_seek_forward_relative_to_current(self):
-        with LZMAFile(fileobj=BytesIO(COMPRESSED_XZ)) as f:
+        with LZMAFile(BytesIO(COMPRESSED_XZ)) as f:
             f.read(100)
             f.seek(1236, 1)
             self.assertEqual(f.read(), INPUT[1336:])
 
     def test_seek_forward_relative_to_end(self):
-        with LZMAFile(fileobj=BytesIO(COMPRESSED_XZ)) as f:
+        with LZMAFile(BytesIO(COMPRESSED_XZ)) as f:
             f.seek(-555, 2)
             self.assertEqual(f.read(), INPUT[-555:])
 
     def test_seek_backward(self):
-        with LZMAFile(fileobj=BytesIO(COMPRESSED_XZ)) as f:
+        with LZMAFile(BytesIO(COMPRESSED_XZ)) as f:
             f.read(1001)
             f.seek(211)
             self.assertEqual(f.read(), INPUT[211:])
 
     def test_seek_backward_across_streams(self):
-        with LZMAFile(fileobj=BytesIO(COMPRESSED_XZ * 2)) as f:
+        with LZMAFile(BytesIO(COMPRESSED_XZ * 2)) as f:
             f.read(len(INPUT) + 333)
             f.seek(737)
             self.assertEqual(f.read(), INPUT[737:] + INPUT)
 
     def test_seek_backward_relative_to_end(self):
-        with LZMAFile(fileobj=BytesIO(COMPRESSED_XZ)) as f:
+        with LZMAFile(BytesIO(COMPRESSED_XZ)) as f:
             f.seek(-150, 2)
             self.assertEqual(f.read(), INPUT[-150:])
 
     def test_seek_past_end(self):
-        with LZMAFile(fileobj=BytesIO(COMPRESSED_XZ)) as f:
+        with LZMAFile(BytesIO(COMPRESSED_XZ)) as f:
             f.seek(len(INPUT) + 9001)
             self.assertEqual(f.tell(), len(INPUT))
             self.assertEqual(f.read(), b"")
 
     def test_seek_past_start(self):
-        with LZMAFile(fileobj=BytesIO(COMPRESSED_XZ)) as f:
+        with LZMAFile(BytesIO(COMPRESSED_XZ)) as f:
             f.seek(-88)
             self.assertEqual(f.tell(), 0)
             self.assertEqual(f.read(), INPUT)
 
     def test_seek_bad_args(self):
-        f = LZMAFile(fileobj=BytesIO(COMPRESSED_XZ))
+        f = LZMAFile(BytesIO(COMPRESSED_XZ))
         f.close()
         self.assertRaises(ValueError, f.seek, 0)
-        with LZMAFile(fileobj=BytesIO(), mode="w") as f:
+        with LZMAFile(BytesIO(), "w") as f:
             self.assertRaises(ValueError, f.seek, 0)
-        with LZMAFile(fileobj=BytesIO(COMPRESSED_XZ)) as f:
+        with LZMAFile(BytesIO(COMPRESSED_XZ)) as f:
             self.assertRaises(ValueError, f.seek, 0, 3)
             self.assertRaises(ValueError, f.seek, 9, ())
             self.assertRaises(TypeError, f.seek, None)
             self.assertRaises(TypeError, f.seek, b"derp")
 
     def test_tell(self):
-        with LZMAFile(fileobj=BytesIO(COMPRESSED_XZ)) as f:
+        with LZMAFile(BytesIO(COMPRESSED_XZ)) as f:
             pos = 0
             while True:
                 self.assertEqual(f.tell(), pos)
@@ -918,14 +908,14 @@ class FileTestCase(unittest.TestCase):
                     break
                 pos += len(result)
             self.assertEqual(f.tell(), len(INPUT))
-        with LZMAFile(fileobj=BytesIO(), mode="w") as f:
+        with LZMAFile(BytesIO(), "w") as f:
             for pos in range(0, len(INPUT), 144):
                 self.assertEqual(f.tell(), pos)
                 f.write(INPUT[pos:pos+144])
             self.assertEqual(f.tell(), len(INPUT))
 
     def test_tell_bad_args(self):
-        f = LZMAFile(fileobj=BytesIO(COMPRESSED_XZ))
+        f = LZMAFile(BytesIO(COMPRESSED_XZ))
         f.close()
         self.assertRaises(ValueError, f.tell)
 
diff --git a/Misc/NEWS b/Misc/NEWS
index e46e99d307..24eeeaaa32 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -18,8 +18,8 @@ Library
 - The bz2 module now contains an open() function, allowing compressed files to
   conveniently be opened in text mode as well as binary mode.
 
-- BZ2File.__init__() now accepts a file object as its first argument, rather
-  than requiring a separate "fileobj" argument.
+- BZ2File.__init__() and LZMAFile.__init__() now accept a file object as their
+  first argument, rather than requiring a separate "fileobj" argument.
 
 - gzip.open() now accepts file objects as well as filenames.