import ast
from typing import List, Optional, Tuple
from ._importlib import _resolve_name
class _ExtractModuleReferences(ast.NodeVisitor):
"""
Extract the list of global variables a block of code will read and write
"""
@classmethod
def run(cls, src: str, package: str) -> List[Tuple[str, Optional[str]]]:
visitor = cls(package)
tree = ast.parse(src)
visitor.visit(tree)
return list(visitor.references.keys())
def __init__(self, package):
super().__init__()
self.package = package
self.references = {}
def _absmodule(self, module_name: str, level: int) -> str:
if level > 0:
return _resolve_name(module_name, self.package, level)
return module_name
def visit_Import(self, node):
for alias in node.names:
self.references[(alias.name, None)] = True
def visit_ImportFrom(self, node):
name = self._absmodule(node.module, 0 if node.level is None else node.level)
for alias in node.names:
# from my_package import foo
# foo may be a module, so we have to add it to the list of
# potential references, if import of it fails, we will ignore it
if alias.name != "*":
self.references[(name, alias.name)] = True
else:
self.references[(name, None)] = True
def _grab_node_int(self, node):
return node.value
def _grab_node_str(self, node):
return node.value
def visit_Call(self, node):
# __import__ calls aren't routed to the visit_Import/From nodes
if hasattr(node.func, "id") and node.func.id == "__import__":
try:
name = self._grab_node_str(node.args[0])
fromlist = []
level = 0
if len(node.args) > 3:
for v in node.args[3].elts:
fromlist.append(self._grab_node_str(v))
elif hasattr(node, "keywords"):
for keyword in node.keywords:
if keyword.arg == "fromlist":
for v in keyword.value.elts:
fromlist.append(self._grab_node_str(v))
if len(node.args) > 4:
level = self._grab_node_int(node.args[4])
elif hasattr(node, "keywords"):
for keyword in node.keywords:
if keyword.arg == "level":
level = self._grab_node_int(keyword.value)
if fromlist == []:
# the top-level package (the name up till the first dot) is returned
# when the fromlist argument is empty in normal import system,
# we need to include top level package to match this behavior and last
# level package to capture the intended dependency of user
self.references[(name, None)] = True
top_name = name.rsplit(".", maxsplit=1)[0]
if top_name != name:
top_name = self._absmodule(top_name, level)
self.references[(top_name, None)] = True
else:
name = self._absmodule(name, level)
for alias in fromlist:
# fromlist args may be submodules, so we have to add the fromlist args
# to the list of potential references. If import of an arg fails we
# will ignore it, similar to visit_ImportFrom
if alias != "*":
self.references[(name, alias)] = True
else:
self.references[(name, None)] = True
except Exception as e:
return
find_files_source_depends_on = _ExtractModuleReferences.run