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visitor.py
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visitor.py
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"""Code parsing and data extraction utilies.
This module exposes a public function, [`visit()`][griffe.agents.visitor.visit],
which parses the module code using [`parse()`][ast.parse],
and returns a new [`Module`][griffe.dataclasses.Module] instance,
populating its members recursively, by using a [`NodeVisitor`][ast.NodeVisitor]-like class.
"""
from __future__ import annotations
import ast
from contextlib import suppress
from itertools import zip_longest
from typing import TYPE_CHECKING, Any, Iterable
from griffe.agents.nodes import (
ast_children,
ast_kind,
ast_next,
get_docstring,
get_instance_names,
get_names,
relative_to_absolute,
safe_get__all__,
safe_get_annotation,
safe_get_base_class,
safe_get_condition,
safe_get_expression,
)
from griffe.collections import LinesCollection, ModulesCollection
from griffe.dataclasses import (
Alias,
Attribute,
Class,
Decorator,
Docstring,
Function,
Kind,
Module,
Parameter,
ParameterKind,
Parameters,
)
from griffe.exceptions import AliasResolutionError, CyclicAliasError, LastNodeError
from griffe.expressions import Expression
from griffe.extensions import Extensions
if TYPE_CHECKING:
from pathlib import Path
from griffe.docstrings.parsers import Parser
from griffe.expressions import Name
builtin_decorators = {
"property": "property",
"staticmethod": "staticmethod",
"classmethod": "classmethod",
}
stdlib_decorators = {
"abc.abstractmethod": {"abstractmethod"},
"functools.cache": {"cached"},
"functools.cached_property": {"cached", "property"},
"cached_property.cached_property": {"cached", "property"},
"functools.lru_cache": {"cached"},
"dataclasses.dataclass": {"dataclass"},
}
typing_overload = {"typing.overload", "typing_extensions.overload"}
def visit(
module_name: str,
filepath: Path,
code: str,
*,
extensions: Extensions | None = None,
parent: Module | None = None,
docstring_parser: Parser | None = None,
docstring_options: dict[str, Any] | None = None,
lines_collection: LinesCollection | None = None,
modules_collection: ModulesCollection | None = None,
) -> Module:
"""Parse and visit a module file.
Parameters:
module_name: The module name (as when importing [from] it).
filepath: The module file path.
code: The module contents.
extensions: The extensions to use when visiting the AST.
parent: The optional parent of this module.
docstring_parser: The docstring parser to use. By default, no parsing is done.
docstring_options: Additional docstring parsing options.
lines_collection: A collection of source code lines.
modules_collection: A collection of modules.
Returns:
The module, with its members populated.
"""
return Visitor(
module_name,
filepath,
code,
extensions or Extensions(),
parent,
docstring_parser=docstring_parser,
docstring_options=docstring_options,
lines_collection=lines_collection,
modules_collection=modules_collection,
).get_module()
class Visitor:
"""This class is used to instantiate a visitor.
Visitors iterate on AST nodes to extract data from them.
"""
def __init__(
self,
module_name: str,
filepath: Path,
code: str,
extensions: Extensions,
parent: Module | None = None,
docstring_parser: Parser | None = None,
docstring_options: dict[str, Any] | None = None,
lines_collection: LinesCollection | None = None,
modules_collection: ModulesCollection | None = None,
) -> None:
"""Initialize the visitor.
Parameters:
module_name: The module name.
filepath: The module filepath.
code: The module source code.
extensions: The extensions to use when visiting.
parent: An optional parent for the final module object.
docstring_parser: The docstring parser to use.
docstring_options: The docstring parsing options.
lines_collection: A collection of source code lines.
modules_collection: A collection of modules.
"""
super().__init__()
self.module_name: str = module_name
self.filepath: Path = filepath
self.code: str = code
self.extensions: Extensions = extensions.attach_visitor(self)
self.parent: Module | None = parent
self.current: Module | Class = None # type: ignore[assignment]
self.docstring_parser: Parser | None = docstring_parser
self.docstring_options: dict[str, Any] = docstring_options or {}
self.lines_collection: LinesCollection = lines_collection or LinesCollection()
self.modules_collection: ModulesCollection = modules_collection or ModulesCollection()
self.type_guarded: bool = False
def _get_docstring(self, node: ast.AST, *, strict: bool = False) -> Docstring | None:
value, lineno, endlineno = get_docstring(node, strict=strict)
if value is None:
return None
return Docstring(
value,
lineno=lineno,
endlineno=endlineno,
parser=self.docstring_parser,
parser_options=self.docstring_options,
)
def get_module(self) -> Module:
"""Build and return the object representing the module attached to this visitor.
This method triggers a complete visit of the module nodes.
Returns:
A module instance.
"""
# optimization: equivalent to ast.parse, but with optimize=1 to remove assert statements
# TODO: with options, could use optimize=2 to remove docstrings
top_node = compile(self.code, mode="exec", filename=str(self.filepath), flags=ast.PyCF_ONLY_AST, optimize=1)
self.visit(top_node)
return self.current.module
def visit(self, node: ast.AST) -> None:
"""Extend the base visit with extensions.
Parameters:
node: The node to visit.
"""
for before_visitor in self.extensions.before_visit:
before_visitor.visit(node)
getattr(self, f"visit_{ast_kind(node)}", self.generic_visit)(node)
for after_visitor in self.extensions.after_visit:
after_visitor.visit(node)
def generic_visit(self, node: ast.AST) -> None:
"""Extend the base generic visit with extensions.
Parameters:
node: The node to visit.
"""
for before_visitor in self.extensions.before_children_visit:
before_visitor.visit(node)
for child in ast_children(node):
self.visit(child)
for after_visitor in self.extensions.after_children_visit:
after_visitor.visit(node)
def visit_module(self, node: ast.Module) -> None:
"""Visit a module node.
Parameters:
node: The node to visit.
"""
self.extensions.call("on_node", node=node)
self.extensions.call("on_module_node", node=node)
self.current = module = Module(
name=self.module_name,
filepath=self.filepath,
parent=self.parent,
docstring=self._get_docstring(node),
lines_collection=self.lines_collection,
modules_collection=self.modules_collection,
)
self.extensions.call("on_instance", node=node, obj=module)
self.extensions.call("on_module_instance", node=node, mod=module)
self.generic_visit(node)
self.extensions.call("on_members", node=node, obj=module)
self.extensions.call("on_module_members", node=node, mod=module)
def visit_classdef(self, node: ast.ClassDef) -> None:
"""Visit a class definition node.
Parameters:
node: The node to visit.
"""
self.extensions.call("on_node", node=node)
self.extensions.call("on_class_node", node=node)
# handle decorators
decorators = []
if node.decorator_list:
lineno = node.decorator_list[0].lineno
for decorator_node in node.decorator_list:
decorators.append(
Decorator(
safe_get_expression(decorator_node, parent=self.current, parse_strings=False), # type: ignore[arg-type]
lineno=decorator_node.lineno,
endlineno=decorator_node.end_lineno,
),
)
else:
lineno = node.lineno
# handle base classes
bases = []
if node.bases:
for base in node.bases:
bases.append(safe_get_base_class(base, parent=self.current))
class_ = Class(
name=node.name,
lineno=lineno,
endlineno=node.end_lineno,
docstring=self._get_docstring(node),
decorators=decorators,
bases=bases, # type: ignore[arg-type]
runtime=not self.type_guarded,
)
class_.labels |= self.decorators_to_labels(decorators)
self.current.set_member(node.name, class_)
self.current = class_
self.extensions.call("on_instance", node=node, obj=class_)
self.extensions.call("on_class_instance", node=node, cls=class_)
self.generic_visit(node)
self.extensions.call("on_members", node=node, obj=class_)
self.extensions.call("on_class_members", node=node, cls=class_)
self.current = self.current.parent # type: ignore[assignment]
def decorators_to_labels(self, decorators: list[Decorator]) -> set[str]:
"""Build and return a set of labels based on decorators.
Parameters:
decorators: The decorators to check.
Returns:
A set of labels.
"""
labels = set()
for decorator in decorators:
callable_path = decorator.callable_path
if callable_path in builtin_decorators:
labels.add(builtin_decorators[callable_path])
elif callable_path in stdlib_decorators:
labels |= stdlib_decorators[callable_path]
return labels
def get_base_property(self, decorators: list[Decorator], function: Function) -> str | None:
"""Check decorators to return the base property in case of setters and deleters.
Parameters:
decorators: The decorators to check.
Returns:
base_property: The property for which the setter/deleted is set.
property_function: Either `"setter"` or `"deleter"`.
"""
for decorator in decorators:
try:
path, prop_function = decorator.callable_path.rsplit(".", 1)
except ValueError:
continue
property_setter_or_deleter = (
prop_function in {"setter", "deleter"}
and path == function.path
and self.current.get_member(function.name).has_labels({"property"})
)
if property_setter_or_deleter:
return prop_function
return None
def handle_function(self, node: ast.AsyncFunctionDef | ast.FunctionDef, labels: set | None = None) -> None:
"""Handle a function definition node.
Parameters:
node: The node to visit.
labels: Labels to add to the data object.
"""
self.extensions.call("on_node", node=node)
self.extensions.call("on_function_node", node=node)
labels = labels or set()
# handle decorators
decorators = []
overload = False
if node.decorator_list:
lineno = node.decorator_list[0].lineno
for decorator_node in node.decorator_list:
decorator_value = safe_get_expression(decorator_node, parent=self.current, parse_strings=False)
if decorator_value is None:
continue
decorator = Decorator(
decorator_value,
lineno=decorator_node.lineno,
endlineno=decorator_node.end_lineno,
)
decorators.append(decorator)
overload |= decorator.callable_path in typing_overload
else:
lineno = node.lineno
labels |= self.decorators_to_labels(decorators)
if "property" in labels:
attribute = Attribute(
name=node.name,
value=None,
annotation=safe_get_annotation(node.returns, parent=self.current),
lineno=node.lineno,
endlineno=node.end_lineno,
docstring=self._get_docstring(node),
runtime=not self.type_guarded,
)
attribute.labels |= labels
self.current.set_member(node.name, attribute)
self.extensions.call("on_instance", node=node, obj=attribute)
self.extensions.call("on_attribute_instance", node=node, attr=attribute)
return
# handle parameters
parameters = Parameters()
annotation: str | Name | Expression | None
posonlyargs = node.args.posonlyargs
# TODO: probably some optimizations to do here
args_kinds_defaults: Iterable = reversed(
(
*zip_longest(
reversed(
(
*zip_longest(
posonlyargs,
[],
fillvalue=ParameterKind.positional_only,
),
*zip_longest(node.args.args, [], fillvalue=ParameterKind.positional_or_keyword),
),
),
reversed(node.args.defaults),
fillvalue=None,
),
),
)
arg: ast.arg
kind: ParameterKind
arg_default: ast.AST | None
for (arg, kind), arg_default in args_kinds_defaults:
annotation = safe_get_annotation(arg.annotation, parent=self.current)
default = safe_get_expression(arg_default, parent=self.current, parse_strings=False)
parameters.add(Parameter(arg.arg, annotation=annotation, kind=kind, default=default))
if node.args.vararg:
annotation = safe_get_annotation(node.args.vararg.annotation, parent=self.current)
parameters.add(
Parameter(
node.args.vararg.arg,
annotation=annotation,
kind=ParameterKind.var_positional,
default="()",
),
)
# TODO: probably some optimizations to do here
kwargs_defaults: Iterable = reversed(
(
*zip_longest(
reversed(node.args.kwonlyargs),
reversed(node.args.kw_defaults),
fillvalue=None,
),
),
)
kwarg: ast.arg
kwarg_default: ast.AST | None
for kwarg, kwarg_default in kwargs_defaults:
annotation = safe_get_annotation(kwarg.annotation, parent=self.current)
default = safe_get_expression(kwarg_default, parent=self.current, parse_strings=False)
parameters.add(
Parameter(kwarg.arg, annotation=annotation, kind=ParameterKind.keyword_only, default=default),
)
if node.args.kwarg:
annotation = safe_get_annotation(node.args.kwarg.annotation, parent=self.current)
parameters.add(
Parameter(
node.args.kwarg.arg,
annotation=annotation,
kind=ParameterKind.var_keyword,
default="{}",
),
)
function = Function(
name=node.name,
lineno=lineno,
endlineno=node.end_lineno,
parameters=parameters,
returns=safe_get_annotation(node.returns, parent=self.current),
decorators=decorators,
docstring=self._get_docstring(node),
runtime=not self.type_guarded,
parent=self.current,
)
property_function = self.get_base_property(decorators, function)
if overload:
self.current.overloads[function.name].append(function)
elif property_function:
base_property: Function = self.current.members[node.name] # type: ignore[assignment]
if property_function == "setter":
base_property.setter = function
base_property.labels.add("writable")
elif property_function == "deleter":
base_property.deleter = function
base_property.labels.add("deletable")
else:
self.current.set_member(node.name, function)
if self.current.kind in {Kind.MODULE, Kind.CLASS} and self.current.overloads[function.name]:
function.overloads = self.current.overloads[function.name]
del self.current.overloads[function.name]
function.labels |= labels
self.extensions.call("on_instance", node=node, obj=function)
self.extensions.call("on_function_instance", node=node, func=function)
if self.current.kind is Kind.CLASS and function.name == "__init__":
self.current = function # type: ignore[assignment] # temporary assign a function
self.generic_visit(node)
self.current = self.current.parent # type: ignore[assignment]
def visit_functiondef(self, node: ast.FunctionDef) -> None:
"""Visit a function definition node.
Parameters:
node: The node to visit.
"""
self.handle_function(node)
def visit_asyncfunctiondef(self, node: ast.AsyncFunctionDef) -> None:
"""Visit an async function definition node.
Parameters:
node: The node to visit.
"""
self.handle_function(node, labels={"async"})
def visit_import(self, node: ast.Import) -> None:
"""Visit an import node.
Parameters:
node: The node to visit.
"""
for name in node.names:
alias_path = name.name.split(".", 1)[0]
alias_name = name.asname or alias_path.split(".", 1)[0]
self.current.imports[alias_name] = alias_path
self.current.set_member(
alias_name,
Alias(
alias_name,
alias_path,
lineno=node.lineno,
endlineno=node.end_lineno,
runtime=not self.type_guarded,
),
)
def visit_importfrom(self, node: ast.ImportFrom) -> None:
"""Visit an "import from" node.
Parameters:
node: The node to visit.
"""
for name in node.names:
if not node.module and node.level == 1 and not name.asname:
# special case: when being in `a` and doing `from . import b`,
# we are effectively creating a member `b` in `a` that is pointing to `a.b`
# -> cyclic alias! in that case, we just skip it, as both the member and module
# have the same name and can be accessed the same way
continue
alias_path = relative_to_absolute(node, name, self.current.module)
if name.name == "*":
alias_name = alias_path.replace(".", "/")
alias_path = alias_path.replace(".*", "")
else:
alias_name = name.asname or name.name
self.current.imports[alias_name] = alias_path
self.current.set_member(
alias_name,
Alias(
alias_name,
alias_path,
lineno=node.lineno,
endlineno=node.end_lineno,
runtime=not self.type_guarded,
),
)
def handle_attribute(
self,
node: ast.Assign | ast.AnnAssign,
annotation: str | Name | Expression | None = None,
) -> None:
"""Handle an attribute (assignment) node.
Parameters:
node: The node to visit.
annotation: A potential annotation.
"""
self.extensions.call("on_node", node=node)
self.extensions.call("on_attribute_node", node=node)
parent = self.current
labels = set()
if parent.kind is Kind.MODULE:
try:
names = get_names(node)
except KeyError: # unsupported nodes, like subscript
return
labels.add("module-attribute")
elif parent.kind is Kind.CLASS:
try:
names = get_names(node)
except KeyError: # unsupported nodes, like subscript
return
if isinstance(annotation, Expression) and annotation.is_classvar:
# explicit classvar: class attribute only
annotation = annotation[2]
labels.add("class-attribute")
elif node.value:
# attribute assigned at class-level: available in instances as well
labels.add("class-attribute")
labels.add("instance-attribute")
else:
# annotated attribute only: not available at class-level
labels.add("instance-attribute")
elif parent.kind is Kind.FUNCTION:
if parent.name != "__init__":
return
try:
names = get_instance_names(node)
except KeyError: # unsupported nodes, like subscript
return
parent = parent.parent # type: ignore[assignment]
labels.add("instance-attribute")
if not names:
return
value = safe_get_expression(node.value, parent=self.current, parse_strings=False)
try:
docstring = self._get_docstring(ast_next(node), strict=True)
except (LastNodeError, AttributeError):
docstring = None
for name in names:
# TODO: handle assigns like x.y = z
# we need to resolve x.y and add z in its member
if "." in name:
continue
if name in parent.members:
# assigning multiple times
# TODO: might be better to inspect
if isinstance(node.parent, (ast.If, ast.ExceptHandler)): # type: ignore[union-attr]
continue # prefer "no-exception" case
existing_member = parent.members[name]
with suppress(AliasResolutionError, CyclicAliasError):
labels |= existing_member.labels
# forward previous docstring and annotation instead of erasing them
if existing_member.docstring and not docstring:
docstring = existing_member.docstring
with suppress(AttributeError):
if existing_member.annotation and not annotation: # type: ignore[union-attr]
annotation = existing_member.annotation # type: ignore[union-attr]
attribute = Attribute(
name=name,
value=value,
annotation=annotation,
lineno=node.lineno,
endlineno=node.end_lineno,
docstring=docstring,
runtime=not self.type_guarded,
)
attribute.labels |= labels
parent.set_member(name, attribute)
if name == "__all__":
with suppress(AttributeError):
parent.exports = safe_get__all__(node, self.current) # type: ignore[arg-type]
self.extensions.call("on_instance", node=node, obj=attribute)
self.extensions.call("on_attribute_instance", node=node, attr=attribute)
def visit_assign(self, node: ast.Assign) -> None:
"""Visit an assignment node.
Parameters:
node: The node to visit.
"""
self.handle_attribute(node)
def visit_annassign(self, node: ast.AnnAssign) -> None:
"""Visit an annotated assignment node.
Parameters:
node: The node to visit.
"""
self.handle_attribute(node, safe_get_annotation(node.annotation, parent=self.current))
def visit_augassign(self, node: ast.AugAssign) -> None:
"""Visit an augmented assignment node.
Parameters:
node: The node to visit.
"""
with suppress(AttributeError):
all_augment = (
node.target.id == "__all__" # type: ignore[union-attr]
and self.current.is_module
and isinstance(node.op, ast.Add)
)
if all_augment:
# we assume exports is not None at this point
self.current.exports.extend(safe_get__all__(node, self.current)) # type: ignore[arg-type,union-attr]
def visit_if(self, node: ast.If) -> None:
"""Visit an "if" node.
Parameters:
node: The node to visit.
"""
if isinstance(node.parent, (ast.Module, ast.ClassDef)): # type: ignore[attr-defined]
condition = safe_get_condition(node.test, parent=self.current, log_level=None)
if str(condition) in {"typing.TYPE_CHECKING", "TYPE_CHECKING"}:
self.type_guarded = True
self.generic_visit(node)
self.type_guarded = False
__all__ = ["visit", "Visitor"]