bpo-39775: inspect: Change Signature.parameters back to OrderedDict. (GH-18684)

1 files changed, 12 insertions, 10 deletions

diff --git a/Lib/inspect.py b/Lib/inspect.py
index 950bdb2..bb82f96 100644
--- a/Lib/inspect.py
+++ b/Lib/inspect.py
@@ -48,7 +48,7 @@ import warnings
 import functools
 import builtins
 from operator import attrgetter
-from collections import namedtuple
+from collections import namedtuple, OrderedDict
 
 # Create constants for the compiler flags in Include/code.h
 # We try to get them from dis to avoid duplication
@@ -1727,7 +1727,7 @@ def _signature_get_partial(wrapped_sig, partial, extra_args=()):
     """
 
     old_params = wrapped_sig.parameters
-    new_params = {}
+    new_params = OrderedDict(old_params.items())
 
     partial_args = partial.args or ()
     partial_keywords = partial.keywords or {}
@@ -1743,7 +1743,6 @@ def _signature_get_partial(wrapped_sig, partial, extra_args=()):
 
 
     transform_to_kwonly = False
-    kwonly_params = {}  # Keyword only parameters are moved to end.
     for param_name, param in old_params.items():
         try:
             arg_value = ba.arguments[param_name]
@@ -1753,6 +1752,7 @@ def _signature_get_partial(wrapped_sig, partial, extra_args=()):
             if param.kind is _POSITIONAL_ONLY:
                 # If positional-only parameter is bound by partial,
                 # it effectively disappears from the signature
+                new_params.pop(param_name)
                 continue
 
             if param.kind is _POSITIONAL_OR_KEYWORD:
@@ -1771,26 +1771,28 @@ def _signature_get_partial(wrapped_sig, partial, extra_args=()):
                     # multiple values.
                     transform_to_kwonly = True
                     # Set the new default value
-                    param = param.replace(default=arg_value)
+                    new_params[param_name] = param.replace(default=arg_value)
                 else:
                     # was passed as a positional argument
+                    new_params.pop(param.name)
                     continue
 
             if param.kind is _KEYWORD_ONLY:
                 # Set the new default value
-                param = param.replace(default=arg_value)
+                new_params[param_name] = param.replace(default=arg_value)
 
         if transform_to_kwonly:
             assert param.kind is not _POSITIONAL_ONLY
 
             if param.kind is _POSITIONAL_OR_KEYWORD:
-                kwonly_params[param_name] = param.replace(kind=_KEYWORD_ONLY)
+                new_param = new_params[param_name].replace(kind=_KEYWORD_ONLY)
+                new_params[param_name] = new_param
+                new_params.move_to_end(param_name)
             elif param.kind in (_KEYWORD_ONLY, _VAR_KEYWORD):
-                kwonly_params[param_name] = param
-        else:
-            new_params[param_name] = param
+                new_params.move_to_end(param_name)
+            elif param.kind is _VAR_POSITIONAL:
+                new_params.pop(param.name)
 
-    new_params.update(kwonly_params)
     return wrapped_sig.replace(parameters=new_params.values())