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

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:: next
+      The *preset* keyword argument also works for streams.
+
 
 .. class:: TarFile
    :noindex:

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)
@@ -1885,10 +1885,17 @@ def not_compressed(comptype):
 
             if filemode not in ("r", "w"):
                 raise ValueError("mode must be 'r' or 'w'")
+            if "compresslevel" in kwargs and comptype not in ("gz", "bz2"):
+                raise ValueError(
+                    "compresslevel is only valid for w|gz and w|bz2 modes"
+                )
+            if "preset" in kwargs and comptype not in ("xz",):
+                raise ValueError("preset is only valid for w|xz mode")
 
             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:

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 :func:`tarfile.open` when using ``'w|xz'``
+mode.