Issue #15984: Correct PyUnicode_FromObject() and _FromEncodedObject() docs

vadmium · vadmium · commit 20d325574eaa · 2016-04-15T00:56:21.000Z
diff --git a/Doc/c-api/unicode.rst b/Doc/c-api/unicode.rst
@@ -556,14 +556,13 @@ APIs:
 .. c:function:: PyObject* PyUnicode_FromEncodedObject(PyObject *obj, \
                                const char *encoding, const char *errors)
 
-   Coerce an encoded object *obj* to a Unicode object and return a reference with
-   incremented refcount.
+   Decode an encoded object *obj* to a Unicode object.
 
    :class:`bytes`, :class:`bytearray` and other
    :term:`bytes-like objects <bytes-like object>`
    are decoded according to the given *encoding* and using the error handling
    defined by *errors*. Both can be *NULL* to have the interface use the default
-   values (see the next section for details).
+   values (see :ref:`builtincodecs` for details).
 
    All other objects, including Unicode objects, cause a :exc:`TypeError` to be
    set.
@@ -745,8 +744,11 @@ Extension modules can continue using them, as they will not be removed in Python
 
 .. c:function:: PyObject* PyUnicode_FromObject(PyObject *obj)
 
-   Shortcut for ``PyUnicode_FromEncodedObject(obj, NULL, "strict")`` which is used
-   throughout the interpreter whenever coercion to Unicode is needed.
+   Copy an instance of a Unicode subtype to a new true Unicode object if
+   necessary. If *obj* is already a true Unicode object (not a subtype),
+   return the reference with incremented refcount.
+
+   Objects other than Unicode or its subtypes will cause a :exc:`TypeError`.
 
 
 Locale Encoding
diff --git a/Include/unicodeobject.h b/Include/unicodeobject.h
@@ -844,17 +844,13 @@ PyAPI_FUNC(int) PyUnicode_Resize(
     Py_ssize_t length           /* New length */
     );
 
-/* Coerce obj to a Unicode object and return a reference with
-   *incremented* refcount.
+/* Decode obj to an Unicode object.
 
-   Coercion is done in the following way:
+   bytes, bytearray and other bytes-like objects are decoded according to the
+   given encoding and error handler. The encoding and error handler can be
+   NULL to have the interface use UTF-8 and "strict".
 
-   1. bytes, bytearray and other bytes-like objects are decoded
-      under the assumptions that they contain data using the UTF-8
-      encoding. Decoding is done in "strict" mode.
-
-   2. All other objects (including Unicode objects) raise an
-      exception.
+   All other objects (including Unicode objects) raise an exception.
 
    The API returns NULL in case of an error. The caller is responsible
    for decref'ing the returned objects.
@@ -867,13 +863,9 @@ PyAPI_FUNC(PyObject*) PyUnicode_FromEncodedObject(
     const char *errors          /* error handling */
     );
 
-/* Coerce obj to a Unicode object and return a reference with
-   *incremented* refcount.
-
-   Unicode objects are passed back as-is (subclasses are converted to
-   true Unicode objects), all other objects are delegated to
-   PyUnicode_FromEncodedObject(obj, NULL, "strict") which results in
-   using UTF-8 encoding as basis for decoding the object.
+/* Copy an instance of a Unicode subtype to a new true Unicode object if
+   necessary. If obj is already a true Unicode object (not a subtype), return
+   the reference with *incremented* refcount.
 
    The API returns NULL in case of an error. The caller is responsible
    for decref'ing the returned objects.
