gh-102378: don't bother stripping / from __text_signature__ (#102379)

Author: davidhewitt

Lib/inspect.py

@@ -2106,26 +2106,21 @@ def _signature_strip_non_python_syntax(signature):
     Private helper function. Takes a signature in Argument Clinic's
     extended signature format.
 
-    Returns a tuple of three things:
-      * that signature re-rendered in standard Python syntax,
+    Returns a tuple of two things:
+      * that signature re-rendered in standard Python syntax, and
       * the index of the "self" parameter (generally 0), or None if
-        the function does not have a "self" parameter, and
-      * the index of the last "positional only" parameter,
-        or None if the signature has no positional-only parameters.
+        the function does not have a "self" parameter.
     """
 
     if not signature:
-        return signature, None, None
+        return signature, None
 
     self_parameter = None
-    last_positional_only = None
 
     lines = [l.encode('ascii') for l in signature.split('\n') if l]
     generator = iter(lines).__next__
     token_stream = tokenize.tokenize(generator)
 
-    delayed_comma = False
-    skip_next_comma = False
     text = []
     add = text.append
 
@@ -2142,35 +2137,18 @@ def _signature_strip_non_python_syntax(signature):
 
         if type == OP:
             if string == ',':
-                if skip_next_comma:
-                    skip_next_comma = False
-                else:
-                    assert not delayed_comma
-                    delayed_comma = True
-                    current_parameter += 1
-                continue
-
-            if string == '/':
-                assert not skip_next_comma
-                assert last_positional_only is None
-                skip_next_comma = True
-                last_positional_only = current_parameter - 1
-                continue
+                current_parameter += 1
 
         if (type == ERRORTOKEN) and (string == '$'):
             assert self_parameter is None
             self_parameter = current_parameter
             continue
 
-        if delayed_comma:
-            delayed_comma = False
-            if not ((type == OP) and (string == ')')):
-                add(', ')
         add(string)
         if (string == ','):
             add(' ')
     clean_signature = ''.join(text)
-    return clean_signature, self_parameter, last_positional_only
+    return clean_signature, self_parameter
 
 
 def _signature_fromstr(cls, obj, s, skip_bound_arg=True):
@@ -2179,8 +2157,7 @@ def _signature_fromstr(cls, obj, s, skip_bound_arg=True):
     """
     Parameter = cls._parameter_cls
 
-    clean_signature, self_parameter, last_positional_only = \
-        _signature_strip_non_python_syntax(s)
+    clean_signature, self_parameter = _signature_strip_non_python_syntax(s)
 
     program = "def foo" + clean_signature + ": pass"
 
@@ -2269,17 +2246,17 @@ def p(name_node, default_node, default=empty):
         parameters.append(Parameter(name, kind, default=default, annotation=empty))
 
     # non-keyword-only parameters
-    args = reversed(f.args.args)
-    defaults = reversed(f.args.defaults)
-    iter = itertools.zip_longest(args, defaults, fillvalue=None)
-    if last_positional_only is not None:
-        kind = Parameter.POSITIONAL_ONLY
-    else:
-        kind = Parameter.POSITIONAL_OR_KEYWORD
-    for i, (name, default) in enumerate(reversed(list(iter))):
+    total_non_kw_args = len(f.args.posonlyargs) + len(f.args.args)
+    required_non_kw_args = total_non_kw_args - len(f.args.defaults)
+    defaults = itertools.chain(itertools.repeat(None, required_non_kw_args), f.args.defaults)
+
+    kind = Parameter.POSITIONAL_ONLY
+    for (name, default) in zip(f.args.posonlyargs, defaults):
+        p(name, default)
+
+    kind = Parameter.POSITIONAL_OR_KEYWORD
+    for (name, default) in zip(f.args.args, defaults):
         p(name, default)
-        if i == last_positional_only:
-            kind = Parameter.POSITIONAL_OR_KEYWORD
 
     # *args
     if f.args.vararg:

Lib/test/test_inspect.py

@@ -4230,56 +4230,47 @@ def foo(a): pass
 
 class TestSignaturePrivateHelpers(unittest.TestCase):
     def _strip_non_python_syntax(self, input,
-        clean_signature, self_parameter, last_positional_only):
+        clean_signature, self_parameter):
         computed_clean_signature, \
-            computed_self_parameter, \
-            computed_last_positional_only = \
+            computed_self_parameter = \
             inspect._signature_strip_non_python_syntax(input)
         self.assertEqual(computed_clean_signature, clean_signature)
         self.assertEqual(computed_self_parameter, self_parameter)
-        self.assertEqual(computed_last_positional_only, last_positional_only)
 
     def test_signature_strip_non_python_syntax(self):
         self._strip_non_python_syntax(
             "($module, /, path, mode, *, dir_fd=None, " +
                 "effective_ids=False,\n       follow_symlinks=True)",
-            "(module, path, mode, *, dir_fd=None, " +
+            "(module, /, path, mode, *, dir_fd=None, " +
                 "effective_ids=False, follow_symlinks=True)",
-            0,
             0)
 
         self._strip_non_python_syntax(
             "($module, word, salt, /)",
-            "(module, word, salt)",
-            0,
-            2)
+            "(module, word, salt, /)",
+            0)
 
         self._strip_non_python_syntax(
             "(x, y=None, z=None, /)",
-            "(x, y=None, z=None)",
-            None,
-            2)
+            "(x, y=None, z=None, /)",
+            None)
 
         self._strip_non_python_syntax(
             "(x, y=None, z=None)",
             "(x, y=None, z=None)",
-            None,
             None)
 
         self._strip_non_python_syntax(
             "(x,\n    y=None,\n      z = None  )",
             "(x, y=None, z=None)",
-            None,
             None)
 
         self._strip_non_python_syntax(
             "",
             "",
-            None,
             None)
 
         self._strip_non_python_syntax(
-            None,
             None,
             None,
             None)

Misc/NEWS.d/next/Library/2023-03-03-19-53-08.gh-issue-102378.kRdOZc.rst

@@ -0,0 +1 @@
+Private helper method ``inspect._signature_strip_non_python_syntax`` will no longer strip ``/`` from the input string.