remove (un)transform methods

Doc/library/codecs.rst

@@ -1165,8 +1165,7 @@ particular, the following variants typically exist:
 |                    |         | operand                   |
 +--------------------+---------+---------------------------+
 
-The following codecs provide bytes-to-bytes mappings.  They can be used with
+The following codecs provide bytes-to-bytes mappings.
-:meth:`bytes.transform` and :meth:`bytes.untransform`.
 
 +--------------------+---------------------------+---------------------------+
 | Codec              | Aliases                   | Purpose                   |
@@ -1192,8 +1191,7 @@ The following codecs provide bytes-to-bytes mappings.  They can be used with
 |                    |                           | using gzip                |
 +--------------------+---------------------------+---------------------------+
 
-The following codecs provide string-to-string mappings.  They can be used with
+The following codecs provide string-to-string mappings.
-:meth:`str.transform` and :meth:`str.untransform`.
 
 +--------------------+---------------------------+---------------------------+
 | Codec              | Aliases                   | Purpose                   |

Doc/library/stdtypes.rst

@@ -1352,19 +1352,6 @@ functions based on regular expressions.
         "They're Bill's Friends."
 
 
-.. method:: str.transform(encoding, errors='strict')
-
-   Return an encoded version of the string.  In contrast to :meth:`encode`, this
-   method works with codecs that provide string-to-string mappings, and not
-   string-to-bytes mappings.  :meth:`transform` therefore returns a string
-   object.
-
-   The codecs that can be used with this method are listed in
-   :ref:`standard-encodings`.
-
-   .. versionadded:: 3.2
-
-
 .. method:: str.translate(map)
 
    Return a copy of the *s* where all characters have been mapped through the
@@ -1382,14 +1369,6 @@ functions based on regular expressions.
       example).
 
 
-.. method:: str.untransform(encoding, errors='strict')
-
-   Return a decoded version of the string.  This provides the reverse operation
-   of :meth:`transform`.
-
-   .. versionadded:: 3.2
-
-
 .. method:: str.upper()
 
    Return a copy of the string converted to uppercase.
@@ -1821,20 +1800,6 @@ The bytes and bytearray types have an additional class method:
 The maketrans and translate methods differ in semantics from the versions
 available on strings:
 
-.. method:: bytes.transform(encoding, errors='strict')
-            bytearray.transform(encoding, errors='strict')
-
-   Return an encoded version of the bytes object.  In contrast to
-   :meth:`encode`, this method works with codecs that provide bytes-to-bytes
-   mappings, and not string-to-bytes mappings.  :meth:`transform` therefore
-   returns a bytes or bytearray object.
-
-   The codecs that can be used with this method are listed in
-   :ref:`standard-encodings`.
-
-   .. versionadded:: 3.2
-
-
 .. method:: bytes.translate(table[, delete])
             bytearray.translate(table[, delete])
 
@@ -1852,15 +1817,6 @@ available on strings:
       b'rd ths shrt txt'
 
 
-.. method:: bytes.untransform(encoding, errors='strict')
-            bytearray.untransform(encoding, errors='strict')
-
-   Return an decoded version of the bytes object.  This provides the reverse
-   operation of :meth:`transform`.
-
-   .. versionadded:: 3.2
-
-
 .. staticmethod:: bytes.maketrans(from, to)
                   bytearray.maketrans(from, to)
 

Doc/whatsnew/3.2.rst

@@ -406,26 +406,6 @@ Other Language Changes
 
 Some smaller changes made to the core Python language are:
 
-* :class:`bytes` and :class:`str` now have two net methods, *transform* and
-  *untransform*.  These provide analogues to *encode* and *decode* but are used
-  for general purpose str-to-str and bytes-to-bytes transformations rather than
-  Unicode codecs for bytes-to-str and str-to-bytes.
-
-  Along with the new methods, several non-unicode codecs been restored from Python 2.x
-  including *base64*, *bz2*, *hex*, *quopri*, *rot13*, *uu*, and *zlib*.
-
-  >>> t = b'which witch had which witches wrist watch'
-  >>> t.transform('quopri')
-  b'which=20witch=20had=20which=20witches=20wrist=20watch'
-
-  >>> short = t.transform('zlib_codec')
-  >>> len(t), len(short)
-  (41, 38)
-  >>> short.untransform('zlib_codec')
-  b'which witch had which witches wrist watch'
-
-  (From multiple contributors in :issue:`7475`.)
-
 * String formatting for :func:`format` and :meth:`str.format` gained new
   capabilities for the format character **#**.  Previously, for integers in
   binary, octal, or hexadecimal, it caused the output to be prefixed with '0b',

Lib/test/test_bytes.py

@@ -207,11 +207,6 @@ class BaseBytesTest(unittest.TestCase):
         self.assertEqual(b.decode(errors="ignore", encoding="utf8"),
                          "Hello world\n")
 
-    def test_transform(self):
-        b1 = self.type2test(range(256))
-        b2 = b1.transform("base64").untransform("base64")
-        self.assertEqual(b2, b1)
-
     def test_from_int(self):
         b = self.type2test(0)
         self.assertEqual(b, self.type2test())

Lib/test/test_codecs.py

@@ -1691,9 +1691,9 @@ else:
     bytes_transform_encodings.append("bz2_codec")
 
 class TransformCodecTest(unittest.TestCase):
+
     def test_basics(self):
         binput = bytes(range(256))
-        ainput = bytearray(binput)
         for encoding in bytes_transform_encodings:
             # generic codecs interface
             (o, size) = codecs.getencoder(encoding)(binput)
@@ -1702,22 +1702,9 @@ class TransformCodecTest(unittest.TestCase):
             self.assertEqual(size, len(o))
             self.assertEqual(i, binput)
 
-            # transform interface
-            boutput = binput.transform(encoding)
-            aoutput = ainput.transform(encoding)
-            self.assertEqual(boutput, aoutput)
-            self.assertIsInstance(boutput, bytes)
-            self.assertIsInstance(aoutput, bytearray)
-            bback = boutput.untransform(encoding)
-            aback = aoutput.untransform(encoding)
-            self.assertEqual(bback, aback)
-            self.assertEqual(bback, binput)
-            self.assertIsInstance(bback, bytes)
-            self.assertIsInstance(aback, bytearray)
-
     def test_read(self):
         for encoding in bytes_transform_encodings:
-            sin = b"\x80".transform(encoding)
+            sin = codecs.encode(b"\x80", encoding)
             reader = codecs.getreader(encoding)(io.BytesIO(sin))
             sout = reader.read()
             self.assertEqual(sout, b"\x80")
@@ -1726,7 +1713,7 @@ class TransformCodecTest(unittest.TestCase):
         for encoding in bytes_transform_encodings:
             if encoding in ['uu_codec', 'zlib_codec']:
                 continue
-            sin = b"\x80".transform(encoding)
+            sin = codecs.encode(b"\x80", encoding)
             reader = codecs.getreader(encoding)(io.BytesIO(sin))
             sout = reader.readline()
             self.assertEqual(sout, b"\x80")

Misc/NEWS

@@ -42,10 +42,6 @@ Core and Builtins
 
 - Issue #9915: Speed up sorting with a key.
 
-- Issue #7475: Added transform() and untransform() methods to both bytes and
-  string types.  They can be used to access those codecs providing
-  bytes-to-bytes and string-to-string mappings.
-
 - Issue #8685: Speed up set difference ``a - b`` when source set ``a`` is much
   larger than operand ``b``.  Patch by Andrew Bennetts.
 

Objects/bytearrayobject.c

@@ -2488,75 +2488,6 @@ bytearray_decode(PyObject *self, PyObject *args, PyObject *kwargs)
     return PyUnicode_FromEncodedObject(self, encoding, errors);
 }
 
-PyDoc_STRVAR(transform__doc__,
-"B.transform(encoding, errors='strict') -> bytearray\n\
-\n\
-Transform B using the codec registered for encoding. errors may be given\n\
-to set a different error handling scheme.");
-
-static PyObject *
-bytearray_transform(PyObject *self, PyObject *args, PyObject *kwargs)
-{
-    const char *encoding = NULL;
-    const char *errors = NULL;
-    static char *kwlist[] = {"encoding", "errors", 0};
-    PyObject *v, *w;
-
-    if (!PyArg_ParseTupleAndKeywords(args, kwargs, "s|s:transform",
-                                     kwlist, &encoding, &errors))
-        return NULL;
-
-    v = PyCodec_Encode(self, encoding, errors);
-    if (v == NULL)
-        return NULL;
-    if (!PyBytes_Check(v)) {
-        PyErr_Format(PyExc_TypeError,
-                     "encoder did not return a bytes object (type=%.400s)",
-                     Py_TYPE(v)->tp_name);
-        Py_DECREF(v);
-        return NULL;
-    }
-    w = PyByteArray_FromStringAndSize(PyBytes_AS_STRING(v),
-                                      PyBytes_GET_SIZE(v));
-    Py_DECREF(v);
-    return w;
-}
-
-
-PyDoc_STRVAR(untransform__doc__,
-"B.untransform(encoding, errors='strict') -> bytearray\n\
-\n\
-Reverse-transform B using the codec registered for encoding. errors may\n\
-be given to set a different error handling scheme.");
-
-static PyObject *
-bytearray_untransform(PyObject *self, PyObject *args, PyObject *kwargs)
-{
-    const char *encoding = NULL;
-    const char *errors = NULL;
-    static char *kwlist[] = {"encoding", "errors", 0};
-    PyObject *v, *w;
-
-    if (!PyArg_ParseTupleAndKeywords(args, kwargs, "s|s:untransform",
-                                     kwlist, &encoding, &errors))
-        return NULL;
-
-    v = PyCodec_Decode(self, encoding, errors);
-    if (v == NULL)
-        return NULL;
-    if (!PyBytes_Check(v)) {
-        PyErr_Format(PyExc_TypeError,
-                     "decoder did not return a bytes object (type=%.400s)",
-                     Py_TYPE(v)->tp_name);
-        Py_DECREF(v);
-        return NULL;
-    }
-    w = PyByteArray_FromStringAndSize(PyBytes_AS_STRING(v),
-                                      PyBytes_GET_SIZE(v));
-    Py_DECREF(v);
-    return w;
-}
-
 PyDoc_STRVAR(alloc_doc,
 "B.__alloc__() -> int\n\
 \n\
@@ -2851,12 +2782,8 @@ bytearray_methods[] = {
     {"swapcase", (PyCFunction)stringlib_swapcase, METH_NOARGS,
      _Py_swapcase__doc__},
     {"title", (PyCFunction)stringlib_title, METH_NOARGS, _Py_title__doc__},
-    {"transform", (PyCFunction)bytearray_transform, METH_VARARGS | METH_KEYWORDS,
-     transform__doc__},
     {"translate", (PyCFunction)bytearray_translate, METH_VARARGS,
      translate__doc__},
-    {"untransform", (PyCFunction)bytearray_untransform, METH_VARARGS | METH_KEYWORDS,
-     untransform__doc__},
     {"upper", (PyCFunction)stringlib_upper, METH_NOARGS, _Py_upper__doc__},
     {"zfill", (PyCFunction)stringlib_zfill, METH_VARARGS, zfill__doc__},
     {NULL}

Objects/bytesobject.c

@@ -2312,68 +2312,6 @@ bytes_decode(PyObject *self, PyObject *args, PyObject *kwargs)
     return PyUnicode_FromEncodedObject(self, encoding, errors);
 }
 
-PyDoc_STRVAR(transform__doc__,
-"B.transform(encoding, errors='strict') -> bytes\n\
-\n\
-Transform B using the codec registered for encoding. errors may be given\n\
-to set a different error handling scheme.");
-
-static PyObject *
-bytes_transform(PyObject *self, PyObject *args, PyObject *kwargs)
-{
-    const char *encoding = NULL;
-    const char *errors = NULL;
-    static char *kwlist[] = {"encoding", "errors", 0};
-    PyObject *v;
-
-    if (!PyArg_ParseTupleAndKeywords(args, kwargs, "s|s:transform",
-                                     kwlist, &encoding, &errors))
-        return NULL;
-
-    v = PyCodec_Encode(self, encoding, errors);
-    if (v == NULL)
-        return NULL;
-    if (!PyBytes_Check(v)) {
-        PyErr_Format(PyExc_TypeError,
-                     "encoder did not return a bytes object (type=%.400s)",
-                     Py_TYPE(v)->tp_name);
-        Py_DECREF(v);
-        return NULL;
-    }
-    return v;
-}
-
-
-PyDoc_STRVAR(untransform__doc__,
-"B.untransform(encoding, errors='strict') -> bytes\n\
-\n\
-Reverse-transform B using the codec registered for encoding. errors may\n\
-be given to set a different error handling scheme.");
-
-static PyObject *
-bytes_untransform(PyObject *self, PyObject *args, PyObject *kwargs)
-{
-    const char *encoding = NULL;
-    const char *errors = NULL;
-    static char *kwlist[] = {"encoding", "errors", 0};
-    PyObject *v;
-
-    if (!PyArg_ParseTupleAndKeywords(args, kwargs, "s|s:untransform",
-                                     kwlist, &encoding, &errors))
-        return NULL;
-
-    v = PyCodec_Decode(self, encoding, errors);
-    if (v == NULL)
-        return NULL;
-    if (!PyBytes_Check(v)) {
-        PyErr_Format(PyExc_TypeError,
-                     "decoder did not return a bytes object (type=%.400s)",
-                     Py_TYPE(v)->tp_name);
-        Py_DECREF(v);
-        return NULL;
-    }
-    return v;
-}
 
 PyDoc_STRVAR(splitlines__doc__,
 "B.splitlines([keepends]) -> list of lines\n\
@@ -2537,10 +2475,8 @@ bytes_methods[] = {
     {"swapcase", (PyCFunction)stringlib_swapcase, METH_NOARGS,
      _Py_swapcase__doc__},
     {"title", (PyCFunction)stringlib_title, METH_NOARGS, _Py_title__doc__},
-    {"transform", (PyCFunction)bytes_transform, METH_VARARGS | METH_KEYWORDS, transform__doc__},
     {"translate", (PyCFunction)bytes_translate, METH_VARARGS,
      translate__doc__},
-    {"untransform", (PyCFunction)bytes_untransform, METH_VARARGS | METH_KEYWORDS, untransform__doc__},
     {"upper", (PyCFunction)stringlib_upper, METH_NOARGS, _Py_upper__doc__},
     {"zfill", (PyCFunction)stringlib_zfill, METH_VARARGS, zfill__doc__},
     {"__sizeof__", (PyCFunction)bytes_sizeof, METH_NOARGS,

Objects/unicodeobject.c

@@ -7455,44 +7455,6 @@ unicode_encode(PyUnicodeObject *self, PyObject *args, PyObject *kwargs)
     return PyUnicode_AsEncodedString((PyObject *)self, encoding, errors);
 }
 
-PyDoc_STRVAR(transform__doc__,
-             "S.transform(encoding, errors='strict') -> str\n\
-\n\
-Transform S using the codec registered for encoding. errors may be given\n\
-to set a different error handling scheme.");
-
-static PyObject *
-unicode_transform(PyUnicodeObject *self, PyObject *args, PyObject *kwargs)
-{
-    static char *kwlist[] = {"encoding", "errors", 0};
-    char *encoding = NULL;
-    char *errors = NULL;
-
-    if (!PyArg_ParseTupleAndKeywords(args, kwargs, "s|s:transform",
-                                     kwlist, &encoding, &errors))
-        return NULL;
-    return PyUnicode_AsEncodedUnicode((PyObject *)self, encoding, errors);
-}
-
-PyDoc_STRVAR(untransform__doc__,
-             "S.untransform(encoding, errors='strict') -> str\n\
-\n\
-Reverse-transform S using the codec registered for encoding. errors may be\n\
-given to set a different error handling scheme.");
-
-static PyObject *
-unicode_untransform(PyUnicodeObject *self, PyObject *args, PyObject *kwargs)
-{
-    static char *kwlist[] = {"encoding", "errors", 0};
-    char *encoding = NULL;
-    char *errors = NULL;
-
-    if (!PyArg_ParseTupleAndKeywords(args, kwargs, "s|s:untransform",
-                                     kwlist, &encoding, &errors))
-        return NULL;
-    return PyUnicode_AsDecodedUnicode((PyObject *)self, encoding, errors);
-}
-
 PyDoc_STRVAR(expandtabs__doc__,
              "S.expandtabs([tabsize]) -> str\n\
 \n\
@@ -9144,8 +9106,7 @@ static PyMethodDef unicode_methods[] = {
     /* Order is according to common usage: often used methods should
        appear first, since lookup is done sequentially. */
 
-    {"encode", (PyCFunction) unicode_encode, METH_VARARGS | METH_KEYWORDS,
+    {"encode", (PyCFunction) unicode_encode, METH_VARARGS | METH_KEYWORDS, encode__doc__},
-     encode__doc__},
     {"replace", (PyCFunction) unicode_replace, METH_VARARGS, replace__doc__},
     {"split", (PyCFunction) unicode_split, METH_VARARGS, split__doc__},
     {"rsplit", (PyCFunction) unicode_rsplit, METH_VARARGS, rsplit__doc__},
@@ -9190,10 +9151,6 @@ static PyMethodDef unicode_methods[] = {
     {"__format__", (PyCFunction) unicode__format__, METH_VARARGS, p_format__doc__},
     {"maketrans", (PyCFunction) unicode_maketrans,
      METH_VARARGS | METH_STATIC, maketrans__doc__},
-    {"transform", (PyCFunction) unicode_transform, METH_VARARGS | METH_KEYWORDS,
-     transform__doc__},
-    {"untransform", (PyCFunction) unicode_untransform, METH_VARARGS | METH_KEYWORDS,
-     untransform__doc__},
     {"__sizeof__", (PyCFunction) unicode__sizeof__, METH_NOARGS, sizeof__doc__},
 #if 0
     {"capwords", (PyCFunction) unicode_capwords, METH_NOARGS, capwords__doc__},