gh-64660: Do not hardcode the name of the returned variable

Misc/NEWS.d/next/Tools-Demos/2026-08-06-11-40-49.gh-issue-64660.MswRQB.rst

@@ -0,0 +1,3 @@
+Argument Clinic return converters no longer need to hardcode the name of the
+variable returned by the parsing function.
+It is now available as ``data.parser_retval``.

PC/msvcrtmodule.c

@@ -65,17 +65,18 @@ class byte_char_return_converter(CReturnConverter):
  data.declarations.append('char s[1];')
  data.return_value = 's[0]'
  data.return_conversion.append(
-'return_value = PyBytes_FromStringAndSize(s, 1);\n')
+f'{data.parser_retval} = PyBytes_FromStringAndSize(s, 1);\n')
 
 class wchar_t_return_converter(CReturnConverter):
  type = 'wchar_t'
 
  def render(self, function, data):
  self.declare(data)
  data.return_conversion.append(
- 'return_value = PyUnicode_FromOrdinal(_return_value);\n')
+ f'{data.parser_retval} = '
+ f'PyUnicode_FromOrdinal({data.converter_retval});\n')
 [python start generated code]*/
-/*[python end generated code: output=da39a3ee5e6b4b0d input=ff031be44ab3250d]*/
+/*[python end generated code: output=da39a3ee5e6b4b0d input=ed7a4a045a6d0496]*/
 
 /*[clinic input]
 module msvcrt

Tools/clinic/libclinic/clanguage.py

@@ -525,6 +525,7 @@ def render_function(
  template_dict['cleanup'] = libclinic.format_escape("".join(data.cleanup))
 
  template_dict['return_value'] = data.return_value
+ template_dict['parser_retval'] = data.parser_retval
  template_dict['lock'] = "\n".join(data.lock)
  template_dict['unlock'] = "\n".join(data.unlock)
 

Tools/clinic/libclinic/codegen.py

@@ -47,14 +47,17 @@ def __init__(self) -> None:
  # The arguments to the impl function at the time it's called.
  self.impl_arguments: list[str] = []
 
+ # The name of the variable which is returned by the parser.
+ self.parser_retval = "return_value"
+
  # For return converters: the name of the variable that
  # should receive the value returned by the impl.
  self.return_value = "return_value"
 
  # For return converters: the code to convert the return
  # value from the parse function. This is also where
- # you should check the _return_value for errors, and
- # "goto exit" if there are any.
+ # you should check the value returned by the impl for errors,
+ # and "goto exit" if there are any.
  self.return_conversion: list[str] = []
  self.converter_retval = "_return_value"
 

Tools/clinic/libclinic/parse_args.py

@@ -319,7 +319,7 @@ def select_prototypes(self) -> None:
 self.docstring_prototype=''
 self.docstring_definition=''
 self.methoddef_define=METHODDEF_PROTOTYPE_DEFINE
-self.return_value_declaration="PyObject *return_value = NULL;"
+self.return_value_declaration="PyObject *{parser_retval} = NULL;"
 
 ifself.is_new_or_init() andnotself.func.docstring:
 pass
@@ -330,7 +330,7 @@ def select_prototypes(self) -> None:
 elifself.func.kindisSETTER:
 ifself.func.docstring:
 fail("docstrings are only supported for @getter, not @setter")
-self.return_value_declaration="int {return_value};"
+self.return_value_declaration="int {parser_retval};"
 self.methoddef_define=SETTERDEF_PROTOTYPE_DEFINE
 else:
 self.docstring_prototype=DOCSTRING_PROTOTYPE_VAR
@@ -371,7 +371,7 @@ def parser_body(
 
  {exit_label}
  {cleanup}
- return return_value;
+ return {parser_retval};
  }}
  """)
 forfieldinpreamble, *fields, finale:
@@ -860,7 +860,7 @@ def handle_new_or_init(self) -> None:
 ifself.func.kindisMETHOD_NEW:
 self.parser_prototype=PARSER_PROTOTYPE_KEYWORD
 else:
-self.return_value_declaration="int return_value = -1;"
+self.return_value_declaration="int {parser_retval} = -1;"
 self.parser_prototype=PARSER_PROTOTYPE_KEYWORD___INIT__
 
 fields: list[str] =list(self.parser_body_fields)

Tools/clinic/libclinic/return_converters.py

@@ -110,7 +110,8 @@ def render(self, function: Function, data: CRenderData) -> None:
  self.declare(data)
  self.err_occurred_if(f"{data.converter_retval} == -1", data)
  data.return_conversion.append(
- f'return_value = PyBool_FromLong((long){data.converter_retval});\n'
+ f'{data.parser_retval} = '
+ f'PyBool_FromLong((long){data.converter_retval});\n'
  )
 
 
@@ -124,7 +125,8 @@ def render(self, function: Function, data: CRenderData) -> None:
  self.declare(data)
  self.err_occurred_if(f"{data.converter_retval} == {self.unsigned_cast}-1", data)
  data.return_conversion.append(
- f'return_value = {self.conversion_fn}({self.cast}{data.converter_retval});\n'
+ f'{data.parser_retval} = '
+ f'{self.conversion_fn}({self.cast}{data.converter_retval});\n'
  )
 
 
@@ -164,7 +166,8 @@ def render(self, function: Function, data: CRenderData) -> None:
  self.declare(data)
  self.err_occurred_if(f"{data.converter_retval} == -1.0", data)
  data.return_conversion.append(
- f'return_value = PyFloat_FromDouble({self.cast}{data.converter_retval});\n'
+ f'{data.parser_retval} = '
+ f'PyFloat_FromDouble({self.cast}{data.converter_retval});\n'
  )