From 6324ac1293b2cf71559869b88f89f510f9a62a8e Mon Sep 17 00:00:00 2001
From: "Miss Islington (bot)"
 <31488909+miss-islington@users.noreply.github.com>
Date: Sat, 8 Jun 2019 08:15:02 -0700
Subject: [PATCH] bpo-34886: Fix subprocess.run handling of exclusive arguments
 (GH-11727)
MIME-Version: 1.0
Content-Type: text/plain; charset=utf8
Content-Transfer-Encoding: 8bit

Fix an unintended ValueError from :func:`subprocess.run` when checking for
conflicting `input` and `stdin` or `capture_output` and `stdout` or `stderr` args
when they were explicitly provided but with `None` values within a passed in
`**kwargs` dict rather than as passed directly by name.
(cherry picked from commit 8cc605acdda5aff250ab4c9b524a7560f90ca9f3)

Co-authored-by: Rémi Lapeyre <remi.lapeyre@henki.fr>
---
 Lib/subprocess.py                                            | 4 ++--
 .../next/Library/2019-06-08-16-03-19.bpo-34886.Ov-pc9.rst    | 5 +++++
 2 files changed, 7 insertions(+), 2 deletions(-)
 create mode 100644 Misc/NEWS.d/next/Library/2019-06-08-16-03-19.bpo-34886.Ov-pc9.rst

diff --git a/Lib/subprocess.py b/Lib/subprocess.py
index 9e36b9de6b..d34c57828b 100644
--- a/Lib/subprocess.py
+++ b/Lib/subprocess.py
@@ -459,12 +459,12 @@ def run(*popenargs,
     The other arguments are the same as for the Popen constructor.
     """
     if input is not None:
-        if 'stdin' in kwargs:
+        if kwargs.get('stdin') is not None:
             raise ValueError('stdin and input arguments may not both be used.')
         kwargs['stdin'] = PIPE
 
     if capture_output:
-        if ('stdout' in kwargs) or ('stderr' in kwargs):
+        if kwargs.get('stdout') is not None or kwargs.get('stderr') is not None:
             raise ValueError('stdout and stderr arguments may not be used '
                              'with capture_output.')
         kwargs['stdout'] = PIPE
diff --git a/Misc/NEWS.d/next/Library/2019-06-08-16-03-19.bpo-34886.Ov-pc9.rst b/Misc/NEWS.d/next/Library/2019-06-08-16-03-19.bpo-34886.Ov-pc9.rst
new file mode 100644
index 0000000000..1b5fc37025
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2019-06-08-16-03-19.bpo-34886.Ov-pc9.rst
@@ -0,0 +1,5 @@
+Fix an unintended ValueError from :func:`subprocess.run` when checking for
+conflicting `input` and `stdin` or `capture_output` and `stdout` or `stderr`
+args when they were explicitly provided but with `None` values within a
+passed in `**kwargs` dict rather than as passed directly by name. Patch
+contributed by Rémi Lapeyre.
-- 
2.49.0