From: Christopher Head <chead@chead.ca>
Date: Fri, 12 Apr 2019 15:50:41 +0000 (-0700)
Subject: Indicate that seek and tell are mandatory on BufferedRandom. (GH-11216)
X-Git-Tag: v3.8.0a4~206
X-Git-Url: https://granicus.if.org/sourcecode?a=commitdiff_plain;h=b13552c4d7ce68fc9e61b5ade03cb5b951349c2b;p=python

Indicate that seek and tell are mandatory on BufferedRandom. (GH-11216)

For BufferedReader and BufferedWriter, seek and tell operations are
optional (they may or may not exist based on the underlying stream). For
BufferedRandom, they are mandatory: a BufferedRandom should not be
constructed over an unseekable underlying stream. Document this.
---

diff --git a/Doc/library/io.rst b/Doc/library/io.rst
index 9738c5c2ad..0f1251687a 100644
--- a/Doc/library/io.rst
+++ b/Doc/library/io.rst
@@ -719,15 +719,15 @@ than raw I/O does.
 .. class:: BufferedRandom(raw, buffer_size=DEFAULT_BUFFER_SIZE)
 
    A buffered interface to random access streams.  It inherits
-   :class:`BufferedReader` and :class:`BufferedWriter`, and further supports
-   :meth:`seek` and :meth:`tell` functionality.
+   :class:`BufferedReader` and :class:`BufferedWriter`.
 
    The constructor creates a reader and writer for a seekable raw stream, given
    in the first argument.  If the *buffer_size* is omitted it defaults to
    :data:`DEFAULT_BUFFER_SIZE`.
 
    :class:`BufferedRandom` is capable of anything :class:`BufferedReader` or
-   :class:`BufferedWriter` can do.
+   :class:`BufferedWriter` can do.  In addition, :meth:`seek` and :meth:`tell`
+   are guaranteed to be implemented.
 
 
 .. class:: BufferedRWPair(reader, writer, buffer_size=DEFAULT_BUFFER_SIZE)