#18430: Document that peek() may change the position of the underlying file for

the BZ2File, GzipFile and LZMAFile classes.

diff --git a/Doc/library/bz2.rst b/Doc/library/bz2.rst
index 95a5abb75dba2abca09233b29a19e2309c86db72..b79bccdb31e862c09af7decc31c07dfe9b635cef 100644 (file)
--- a/Doc/library/bz2.rst
+++ b/Doc/library/bz2.rst
@@ -91,6 +91,11 @@ All of the classes in this module may safely be accessed from multiple threads.
       byte of data will be returned (unless at EOF). The exact number of bytes
       returned is unspecified.
 
+      .. note:: While calling :meth:`peek` does not change the file position of
+         the :class:`BZ2File`, it may change the position of the underlying file
+         object (e.g. if the :class:`BZ2File` was constructed by passing a file
+         object for *filename*).
+
       .. versionadded:: 3.3
 
    .. versionchanged:: 3.1

diff --git a/Doc/library/gzip.rst b/Doc/library/gzip.rst
index ec16f6ae88b594ddb0ad7ceaf6ff16b089df2524..354deed921a962189c71402580f440d7c675fdba 100644 (file)
--- a/Doc/library/gzip.rst
+++ b/Doc/library/gzip.rst
@@ -113,6 +113,11 @@ The module defines the following items:
       the call.  The number of bytes returned may be more or less than
       requested.
 
+      .. note:: While calling :meth:`peek` does not change the file position of
+         the :class:`GzipFile`, it may change the position of the underlying
+         file object (e.g. if the :class:`GzipFile` was constructed with the
+         *fileobj* parameter).
+
       .. versionadded:: 3.2
 
    .. versionchanged:: 3.1

diff --git a/Doc/library/lzma.rst b/Doc/library/lzma.rst
index da4657551e28909bd8c4606538db1a683d33c57f..07b69eb772a1c7fbfe5cee14fe452b0453c92a00 100644 (file)
--- a/Doc/library/lzma.rst
+++ b/Doc/library/lzma.rst
@@ -98,6 +98,11 @@ Reading and writing compressed files
       byte of data will be returned, unless EOF has been reached. The exact
       number of bytes returned is unspecified (the *size* argument is ignored).
 
+      .. note:: While calling :meth:`peek` does not change the file position of
+         the :class:`LZMAFile`, it may change the position of the underlying
+         file object (e.g. if the :class:`LZMAFile` was constructed by passing a
+         file object for *filename*).
+
 
 Compressing and decompressing data in memory
 --------------------------------------------