sphinx/sphinx/ext/autodoc/preserve_defaults.py
2022-01-01 18:45:03 +09:00

117 lines
4.2 KiB
Python

"""
sphinx.ext.autodoc.preserve_defaults
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Preserve the default argument values of function signatures in source code
and keep them not evaluated for readability.
:copyright: Copyright 2007-2022 by the Sphinx team, see AUTHORS.
:license: BSD, see LICENSE for details.
"""
import ast
import inspect
import sys
from typing import Any, Dict, List, Optional
from sphinx.application import Sphinx
from sphinx.locale import __
from sphinx.pycode.ast import parse as ast_parse
from sphinx.pycode.ast import unparse as ast_unparse
from sphinx.util import logging
logger = logging.getLogger(__name__)
class DefaultValue:
def __init__(self, name: str) -> None:
self.name = name
def __repr__(self) -> str:
return self.name
def get_function_def(obj: Any) -> ast.FunctionDef:
"""Get FunctionDef object from living object.
This tries to parse original code for living object and returns
AST node for given *obj*.
"""
try:
source = inspect.getsource(obj)
if source.startswith((' ', r'\t')):
# subject is placed inside class or block. To read its docstring,
# this adds if-block before the declaration.
module = ast_parse('if True:\n' + source)
return module.body[0].body[0] # type: ignore
else:
module = ast_parse(source)
return module.body[0] # type: ignore
except (OSError, TypeError): # failed to load source code
return None
def get_default_value(lines: List[str], position: ast.AST) -> Optional[str]:
try:
if sys.version_info < (3, 8): # only for py38+
return None
elif position.lineno == position.end_lineno:
line = lines[position.lineno - 1]
return line[position.col_offset:position.end_col_offset]
else:
# multiline value is not supported now
return None
except (AttributeError, IndexError):
return None
def update_defvalue(app: Sphinx, obj: Any, bound_method: bool) -> None:
"""Update defvalue info of *obj* using type_comments."""
if not app.config.autodoc_preserve_defaults:
return
try:
lines = inspect.getsource(obj).splitlines()
if lines[0].startswith((' ', r'\t')):
lines.insert(0, '') # insert a dummy line to follow what get_function_def() does.
except (OSError, TypeError):
lines = []
try:
function = get_function_def(obj)
if function.args.defaults or function.args.kw_defaults:
sig = inspect.signature(obj)
defaults = list(function.args.defaults)
kw_defaults = list(function.args.kw_defaults)
parameters = list(sig.parameters.values())
for i, param in enumerate(parameters):
if param.default is not param.empty:
if param.kind in (param.POSITIONAL_ONLY, param.POSITIONAL_OR_KEYWORD):
default = defaults.pop(0)
value = get_default_value(lines, default)
if value is None:
value = ast_unparse(default) # type: ignore
parameters[i] = param.replace(default=DefaultValue(value))
else:
default = kw_defaults.pop(0)
value = get_default_value(lines, default)
if value is None:
value = ast_unparse(default) # type: ignore
parameters[i] = param.replace(default=DefaultValue(value))
sig = sig.replace(parameters=parameters)
obj.__signature__ = sig
except (AttributeError, TypeError):
# failed to update signature (ex. built-in or extension types)
pass
except NotImplementedError as exc: # failed to ast.unparse()
logger.warning(__("Failed to parse a default argument value for %r: %s"), obj, exc)
def setup(app: Sphinx) -> Dict[str, Any]:
app.add_config_value('autodoc_preserve_defaults', False, True)
app.connect('autodoc-before-process-signature', update_defvalue)
return {
'version': '1.0',
'parallel_read_safe': True
}