bpo-35312: Make lib2to3.pgen2.parse.ParseError round-trip pickle-able. (GH-10710)

Author: asottile

Lib/lib2to3/pgen2/parse.py

@@ -24,6 +24,9 @@ def __init__(self, msg, type, value, context):
  self.value = value
  self.context = context
 
+ def __reduce__(self):
+ return type(self), (self.msg, self.type, self.value, self.context)
+
 class Parser(object):
  """Parser engine.
 

Lib/lib2to3/tests/test_parser.py

@@ -622,6 +622,18 @@ def test_multiline_str_literals(self):
  self.validate(s)
 
 
+class TestPickleableException(unittest.TestCase):
+ def test_ParseError(self):
+ err = ParseError('msg', 2, None, (1, 'context'))
+ for proto in range(pickle.HIGHEST_PROTOCOL + 1):
+ err2 = pickle.loads(pickle.dumps(err, protocol=proto))
+ self.assertEqual(err.args, err2.args)
+ self.assertEqual(err.msg, err2.msg)
+ self.assertEqual(err.type, err2.type)
+ self.assertEqual(err.value, err2.value)
+ self.assertEqual(err.context, err2.context)
+
+
 def diff_texts(a, b, filename):
  a = a.splitlines()
  b = b.splitlines()

Misc/NEWS.d/next/Library/2018-11-25-20-05-33.bpo-35312.wbw0zO.rst

@@ -0,0 +1 @@
+Make ``lib2to3.pgen2.parse.ParseError`` round-trip pickle-able. Patch by Anthony Sottile.