Redo "Parse env configuration in posix mode"

Fixes Supervisor#328

This allows (escaped) quotes in the values as well as empty
values.

This was done in pull request Supervisor#329 but removed as it
broke parsing empty quotes (Supervisor#873) due to a bug in shlex
(http://bugs.python.org/issue21999). This bug is fixed
so posix mode can be used.

Brings back Supervisor#329
Partially reverts Supervisor#880

CHANGES.rst

@@ -9,6 +9,9 @@
   the ``[supervisorctl]`` section or ``[ctlplugin:x]`` sections to be in
   included files.  Patch by François Granade.
 
+- Parsing ``environment=`` has been improved to allow escaped quotes
+  inside quotes and quoted empty values. Patch by Stefan Friesel.
+
 4.2.5 (2022-12-23)
 ------------------
 

supervisor/datatypes.py

@@ -68,7 +68,7 @@ def dict_of_key_value_pairs(arg):
     """ parse KEY=val,KEY2=val2 into {'KEY':'val', 'KEY2':'val2'}
         Quotes can be used to allow commas in the value
     """
-    lexer = shlex.shlex(str(arg))
+    lexer = shlex.shlex(str(arg), posix=True)
     lexer.wordchars += '/.+-():'
 
     tokens = list(lexer)
@@ -81,7 +81,7 @@ def dict_of_key_value_pairs(arg):
         if len(k_eq_v) != 3 or k_eq_v[1] != '=':
             raise ValueError(
                 "Unexpected end of key/value pairs in value '%s'" % arg)
-        D[k_eq_v[0]] = k_eq_v[2].strip('\'"')
+        D[k_eq_v[0]] = k_eq_v[2]
         i += 4
     return D
 

supervisor/tests/test_datatypes.py

@@ -164,6 +164,11 @@ def test_handles_newlines_inside_quotes(self):
         expected = {'foo': 'a\nb\nc'}
         self.assertEqual(actual, expected)
 
+    def test_handles_quotes_inside_quotes(self):
+        actual = datatypes.dict_of_key_value_pairs('foo="\'\\""')
+        expected = {'foo': '\'"'}
+        self.assertEqual(actual, expected)
+
     def test_handles_empty_inside_quotes(self):
         actual = datatypes.dict_of_key_value_pairs('foo=""')
         expected = {'foo': ''}