[Python-checkins] bpo-39957: Change Signature.parameters to OrderedDict (GH-18988)

[Jens Reidel]

https://github.com/python/cpython/commit/611836a69a7a98bb106b4d315ed76a1e17266f4f
commit: 611836a69a7a98bb106b4d315ed76a1e17266f4f
branch: master
author: Jens Reidel <jens at troet.org>
committer: GitHub <noreply at github.com>
date: 2020-03-18T11:22:46+09:00
summary:

bpo-39957: Change Signature.parameters to OrderedDict (GH-18988)

files:
M Lib/inspect.py
M Lib/test/test_inspect.py

diff --git a/Lib/inspect.py b/Lib/inspect.py
index 125bd456a1c46..90435a10caac7 100644
--- a/Lib/inspect.py
+++ b/Lib/inspect.py
@@ -2733,7 +2733,7 @@ class Signature:
 
     A Signature object has the following public attributes and methods:
 
-    * parameters : dict
+    * parameters : OrderedDict
         An ordered mapping of parameters' names to the corresponding
         Parameter objects (keyword-only arguments are in the same order
         as listed in `code.co_varnames`).
@@ -2763,10 +2763,10 @@ def __init__(self, parameters=None, *, return_annotation=_empty,
         """
 
         if parameters is None:
-            params = {}
+            params = OrderedDict()
         else:
             if __validate_parameters__:
-                params = {}
+                params = OrderedDict()
                 top_kind = _POSITIONAL_ONLY
                 kind_defaults = False
 
@@ -2805,7 +2805,7 @@ def __init__(self, parameters=None, *, return_annotation=_empty,
 
                     params[name] = param
             else:
-                params = {param.name: param for param in parameters}
+                params = OrderedDict((param.name, param) for param in parameters)
 
         self._parameters = types.MappingProxyType(params)
         self._return_annotation = return_annotation
diff --git a/Lib/test/test_inspect.py b/Lib/test/test_inspect.py
index 8a2efc879323f..f193807e80473 100644
--- a/Lib/test/test_inspect.py
+++ b/Lib/test/test_inspect.py
@@ -2077,7 +2077,7 @@ def test_signature_object(self):
         P = inspect.Parameter
 
         self.assertEqual(str(S()), '()')
-        self.assertEqual(repr(S().parameters), 'mappingproxy({})')
+        self.assertEqual(repr(S().parameters), 'mappingproxy(OrderedDict())')
 
         def test(po, pk, pod=42, pkd=100, *args, ko, **kwargs):
             pass
@@ -3181,6 +3181,11 @@ def test_signature_definition_order_preserved_on_kwonly(self):
         l = list(signature.parameters)
         self.assertEqual(l, unsorted_keyword_only_parameters)
 
+    def test_signater_parameters_is_ordered(self):
+        p1 = inspect.signature(lambda x, y: None).parameters
+        p2 = inspect.signature(lambda y, x: None).parameters
+        self.assertNotEqual(p1, p2)
+
 
 class TestParameterObject(unittest.TestCase):
     def test_signature_parameter_kinds(self):