# HG changeset patch
# Parent 154ae3af03173ce0f735b6dd47a37da97910f0b9
BufferedReader.peek() normally returns at least one byte


diff -r 154ae3af0317 -r 33431551b059 Doc/library/io.rst
--- a/Doc/library/io.rst	Fri Jan 09 16:40:38 2015 -0600
+++ b/Doc/library/io.rst	Sat Jan 10 04:10:37 2015 +0000
@@ -636,7 +636,9 @@
 
       Return bytes from the stream without advancing the position.  At most one
       single read on the raw stream is done to satisfy the call. The number of
-      bytes returned may be less or more than requested.
+      bytes returned may be less or more than requested, but is
+      guaranteed to be at least one, unless no data is available due to
+      EOF or non-blocking mode.
 
    .. method:: read([size])
 
diff -r 154ae3af0317 -r 33431551b059 Modules/_io/bufferedio.c
--- a/Modules/_io/bufferedio.c	Fri Jan 09 16:40:38 2015 -0600
+++ b/Modules/_io/bufferedio.c	Sat Jan 10 04:10:37 2015 +0000
@@ -1758,9 +1758,9 @@
     /* Fill the buffer from the raw stream, and copy it to the result. */
     _bufferedreader_reset_buf(self);
     r = _bufferedreader_fill_buffer(self);
-    if (r == -1)
+    if (r == -1) /* Exception raised */
         return NULL;
-    if (r == -2)
+    if (r == -2) /* No data in non-blocking mode */
         r = 0;
     self->pos = 0;
     return PyBytes_FromStringAndSize(self->buffer, r);