Index: Doc/library/gzip.rst
===================================================================
--- Doc/library/gzip.rst	(révision 85129)
+++ Doc/library/gzip.rst	(copie de travail)
@@ -70,6 +70,17 @@
    including iteration and the :keyword:`with` statement.  Only the
    :meth:`truncate` method isn't implemented.
 
+   :class:`GzipFile` also provides the following method:
+
+   .. method:: peek([n])
+
+      Read *n* uncompressed bytes without advancing the file position.
+      At most one single read on the compressed stream is done to satisfy
+      the call.  The number of bytes returned may be more or less than
+      requested.
+
+      .. versionadded:: 3.2
+
    .. versionchanged:: 3.1
       Support for the :keyword:`with` statement was added.
 
@@ -79,10 +90,7 @@
    .. versionchanged:: 3.2
       Support for unseekable files was added.
 
-   .. versionchanged:: 3.2
-      The :meth:`peek` method was implemented.
 
-
 .. function:: open(filename, mode='rb', compresslevel=9)
 
    This is a shorthand for ``GzipFile(filename,`` ``mode,`` ``compresslevel)``.
Index: Lib/gzip.py
===================================================================
--- Lib/gzip.py	(révision 85129)
+++ Lib/gzip.py	(copie de travail)
@@ -342,16 +342,18 @@
     def peek(self, n):
         if self.mode != READ:
             import errno
-            raise IOError(errno.EBADF, "read() on write-only GzipFile object")
+            raise IOError(errno.EBADF, "peek() on write-only GzipFile object")
 
-        # Do not return ridiculously small buffers
+        # Do not return ridiculously small buffers, for one common idiom
+        # is to call peek(1) and expect more bytes in return.
         if n < 100:
             n = 100
         if self.extrasize == 0:
             if self.fileobj is None:
                 return b''
             try:
-                self._read(max(self.max_read_chunk, n))
+                # 1024 is the same buffering heuristic used in read()
+                self._read(max(n, 1024))
             except EOFError:
                 pass
         offset = self.offset - self.extrastart