gh-133005: Support tarfile.open(mode="w|xz", preset=...)

mgorny · mgorny · commit ebf37b6e9df5 · 2025-04-26T14:49:39.000+02:00
Support passing the `preset` option to `tarfile.open` when the file
is open with `mode="w|xz"`.  This aligns the behavior with `"w:xz"`
mode.
diff --git a/Doc/library/tarfile.rst b/Doc/library/tarfile.rst
@@ -112,7 +112,7 @@ Some facts and figures:
    ``'w|bz2'``, :func:`tarfile.open` accepts the keyword argument
    *compresslevel* (default ``9``) to specify the compression level of the file.
 
-   For modes ``'w:xz'`` and ``'x:xz'``, :func:`tarfile.open` accepts the
+   For modes ``'w:xz'``, ``'x:xz'`` and ``'w|xz'``, :func:`tarfile.open` accepts the
    keyword argument *preset* to specify the compression level of the file.
 
    For special purposes, there is a second format for *mode*:
@@ -167,6 +167,9 @@ Some facts and figures:
    .. versionchanged:: 3.12
       The *compresslevel* keyword argument also works for streams.
 
+   .. versionchanged:: 3.14
+      The *preset* keyword argument also works for streams.
+
 
 .. class:: TarFile
    :noindex:
diff --git a/Lib/tarfile.py b/Lib/tarfile.py
@@ -339,7 +339,7 @@ class _Stream:
     """
 
     def __init__(self, name, mode, comptype, fileobj, bufsize,
-                 compresslevel):
+                 compresslevel, preset):
         """Construct a _Stream object.
         """
         self._extfileobj = True
@@ -398,7 +398,7 @@ def __init__(self, name, mode, comptype, fileobj, bufsize,
                     self.cmp = lzma.LZMADecompressor()
                     self.exception = lzma.LZMAError
                 else:
-                    self.cmp = lzma.LZMACompressor()
+                    self.cmp = lzma.LZMACompressor(preset=preset)
 
             elif comptype != "tar":
                 raise CompressionError("unknown compression type %r" % comptype)
@@ -1887,8 +1887,9 @@ def not_compressed(comptype):
                 raise ValueError("mode must be 'r' or 'w'")
 
             compresslevel = kwargs.pop("compresslevel", 9)
+            preset = kwargs.pop("preset", None)
             stream = _Stream(name, filemode, comptype, fileobj, bufsize,
-                             compresslevel)
+                             compresslevel, preset)
             try:
                 t = cls(name, filemode, stream, **kwargs)
             except:
diff --git a/Misc/NEWS.d/next/Library/2025-04-26-14-44-21.gh-issue-133005.y4SRfk.rst b/Misc/NEWS.d/next/Library/2025-04-26-14-44-21.gh-issue-133005.y4SRfk.rst
@@ -0,0 +1,2 @@
+Support passing ``preset`` option to ``tarfile.open()`` when using ``w|xz``
+mode.

Original file line number	Diff line number	Diff line change
`@@ -0,0 +1,2 @@`
	`1`	+Support passing ``preset`` option to ``tarfile.open()`` when using ``w\|xz``
	`2`	`+mode.`