[docs] [issue17814] Popen.stdin/stdout/stderr documentation should mention object type

[Nikolaus Rath]

New submission from Nikolaus Rath:

The subprocess documentation currently just says that Popen.stdin et all are "file objects", which is linked to the glossary entry. This isn't very helpful, as it doesn't tell whether the streams are bytes or text streams.

Suggested patch:

diff --git a/Doc/library/subprocess.rst b/Doc/library/subprocess.rst
--- a/Doc/library/subprocess.rst
+++ b/Doc/library/subprocess.rst
@@ -677,21 +677,29 @@
 
 .. attribute:: Popen.stdin
 
-   If the *stdin* argument was :data:`PIPE`, this attribute is a :term:`file
-   object` that provides input to the child process.  Otherwise, it is ``None``.
+   If the *stdin* argument was :data:`PIPE`, this attribute is a
+   :class:`io.BufferedWriter` (if the *universal_newlines* argument
+   was False) or :class:`io.TextIOWrapper` (if the
+   *universal_newlines* argument was True) object that provides input
+   to the child process. Otherwise, it is ``None``.
 
 
 .. attribute:: Popen.stdout
 
-   If the *stdout* argument was :data:`PIPE`, this attribute is a :term:`file
-   object` that provides output from the child process.  Otherwise, it is ``None``.
+   If the *stdout* argument was :data:`PIPE`, this attribute is a
+   :class:`io.BufferedReader` (if the *universal_newlines* argument
+   was False) or :class:`io.TextIOWrapper` (if the
+   *universal_newlines* argument was True) object that provides output
+   from the child process. Otherwise, it is ``None``.
 
 
 .. attribute:: Popen.stderr
 
-   If the *stderr* argument was :data:`PIPE`, this attribute is a :term:`file
-   object` that provides error output from the child process.  Otherwise, it is
-   ``None``.
+   If the *stderr* argument was :data:`PIPE`, this attribute is a
+   :class:`io.BufferedReader` (if the *universal_newlines* argument
+   was False) or :class:`io.TextIOWrapper` (if the
+   *universal_newlines* argument was True) object that provides output
+   from the child process. Otherwise, it is ``None``.
 
 
 .. attribute:: Popen.pid

----------
assignee: docs at python
components: Documentation
messages: 187535
nosy: Nikratio, docs at python
priority: normal
severity: normal
status: open
title: Popen.stdin/stdout/stderr documentation should mention object type
type: enhancement

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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue17814>
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