From 9965f1b8e01a662d6980a299dfac8c2ed25df37f Mon Sep 17 00:00:00 2001
From: Alex Shkop <ashkop@sciforce.solutions>
Date: Mon, 21 Jan 2019 10:45:16 +0200
Subject: [PATCH 1/3] bpo-35168: Documentation about shlex.punctuation_chars
 now states that it should be set in __init__.py

---
 Doc/library/shlex.rst | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/Doc/library/shlex.rst b/Doc/library/shlex.rst
index fb335c69006816..d5b5ec6b14e476 100644
--- a/Doc/library/shlex.rst
+++ b/Doc/library/shlex.rst
@@ -98,7 +98,9 @@ The :mod:`shlex` module defines the following class:
    characters, those characters will be used as the punctuation characters.  Any
    characters in the :attr:`wordchars` attribute that appear in
    *punctuation_chars* will be removed from :attr:`wordchars`.  See
-   :ref:`improved-shell-compatibility` for more information.
+   :ref:`improved-shell-compatibility` for more information. *punctuation_chars*
+   can be set only upon :class:`~shlex.shlex` instance creation and can't be
+   modified later.
 
    .. versionchanged:: 3.6
       The *punctuation_chars* parameter was added.
@@ -299,8 +301,8 @@ variables which either control lexical analysis or can be used for debugging:
 
 .. attribute:: shlex.punctuation_chars
 
-   Characters that will be considered punctuation. Runs of punctuation
-   characters will be returned as a single token. However, note that no
+   A read-only property. Characters that will be considered punctuation. Runs of
+   punctuation characters will be returned as a single token. However, note that no
    semantic validity checking will be performed: for example, '>>>' could be
    returned as a token, even though it may not be recognised as such by shells.
 

From a65944d31b05f46eb22e86da7dc4c2590ae3a0ea Mon Sep 17 00:00:00 2001
From: Alex Shkop <ashkop@sciforce.solutions>
Date: Mon, 21 Jan 2019 11:35:12 +0200
Subject: [PATCH 2/3] bpo-35168: Convert shlex.punctuation_chars to read-only
 property

---
 Lib/shlex.py           | 6 +++++-
 Lib/test/test_shlex.py | 7 +++++++
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/Lib/shlex.py b/Lib/shlex.py
index 2c9786c517a350..195dc12bbce95e 100644
--- a/Lib/shlex.py
+++ b/Lib/shlex.py
@@ -55,7 +55,7 @@ def __init__(self, instream=None, infile=None, posix=False,
             punctuation_chars = ''
         elif punctuation_chars is True:
             punctuation_chars = '();<>|&'
-        self.punctuation_chars = punctuation_chars
+        self._punctuation_chars = punctuation_chars
         if punctuation_chars:
             # _pushback_chars is a push back queue used by lookahead logic
             self._pushback_chars = deque()
@@ -65,6 +65,10 @@ def __init__(self, instream=None, infile=None, posix=False,
             t = self.wordchars.maketrans(dict.fromkeys(punctuation_chars))
             self.wordchars = self.wordchars.translate(t)
 
+    @property
+    def punctuation_chars(self):
+        return self._punctuation_chars
+
     def push_token(self, tok):
         "Push a token onto the stack popped by the get_token method"
         if self.debug >= 1:
diff --git a/Lib/test/test_shlex.py b/Lib/test/test_shlex.py
index fd35788e81b272..8594a6db30b5dc 100644
--- a/Lib/test/test_shlex.py
+++ b/Lib/test/test_shlex.py
@@ -308,6 +308,13 @@ def testQuote(self):
             self.assertEqual(shlex.quote("test%s'name'" % u),
                              "'test%s'\"'\"'name'\"'\"''" % u)
 
+    def testPunctuationCharsReadOnly(self):
+        punctuation_chars = "/|$%^"
+        shlex_instance = shlex.shlex(punctuation_chars=punctuation_chars)
+        self.assertEqual(shlex_instance.punctuation_chars, punctuation_chars)
+        with self.assertRaises(AttributeError):
+            shlex_instance.punctuation_chars = False
+
 # Allow this test to be used with old shlex.py
 if not getattr(shlex, "split", None):
     for methname in dir(ShlexTest):

From 34b1823bad99ef873c607c7d759624cf3b00d033 Mon Sep 17 00:00:00 2001
From: Alex Shkop <ashkop@sciforce.solutions>
Date: Tue, 22 Jan 2019 09:37:35 +0200
Subject: [PATCH 3/3] Add NEWS.d entry

---
 .../NEWS.d/next/Library/2019-01-22-09-23-20.bpo-35168.UGv2yW.rst | 1 +
 1 file changed, 1 insertion(+)
 create mode 100644 Misc/NEWS.d/next/Library/2019-01-22-09-23-20.bpo-35168.UGv2yW.rst

diff --git a/Misc/NEWS.d/next/Library/2019-01-22-09-23-20.bpo-35168.UGv2yW.rst b/Misc/NEWS.d/next/Library/2019-01-22-09-23-20.bpo-35168.UGv2yW.rst
new file mode 100644
index 00000000000000..10684fdbde2f19
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2019-01-22-09-23-20.bpo-35168.UGv2yW.rst
@@ -0,0 +1 @@
+:attr:`shlex.shlex.punctuation_chars` is now a read-only property.