import argparse
import ast
import collections
import configparser
import contextlib
import os.path
import re
import subprocess
import tokenize
from typing import DefaultDict
from typing import Generator
from typing import List
from typing import NewType
from typing import Optional
from typing import Pattern
from typing import Sequence
from typing import Set
from typing import Tuple
from identify.identify import tags_from_path
FileLine = NewType('FileLine', str)
UsageMap = DefaultDict[str, Set[FileLine]]
# https://github.com/python/typed_ast/blob/55420396/ast27/Parser/tokenizer.c#L102-L104
TYPE_COMMENT_RE = re.compile(r'^#\s*type:\s*')
# https://github.com/python/typed_ast/blob/55420396/ast27/Parser/tokenizer.c#L1400
TYPE_IGNORE_RE = re.compile(TYPE_COMMENT_RE.pattern + r'ignore\s*(#|$)')
# https://github.com/python/typed_ast/blob/55420396/ast27/Grammar/Grammar#L147
TYPE_FUNC_RE = re.compile(r'^(\(.*?\))\s*->\s*(.*)$')
DISABLE_COMMENT_RE = re.compile(r'\bdead\s*:\s*disable')
STUB_EXCEPTIONS = frozenset(('AssertionError', 'NotImplementedError'))
class Scope:
def __init__(self) -> None:
self.reads: UsageMap = collections.defaultdict(set)
self.defines: UsageMap = collections.defaultdict(set)
self.reads_tests: UsageMap = collections.defaultdict(set)
class Visitor(ast.NodeVisitor):
def __init__(self) -> None:
self.filename = ''
self.is_test = False
self.previous_scopes: List[Scope] = []
self.scopes = [Scope()]
self.disabled: Set[FileLine] = set()
@contextlib.contextmanager
def file_ctx(
self,
filename: str,
*,
is_test: bool,
) -> Generator[None, None, None]:
orig_filename, self.filename = self.filename, filename
orig_is_test, self.is_test = self.is_test, is_test
try:
yield
finally:
self.filename = orig_filename
self.is_test = orig_is_test
@contextlib.contextmanager
def scope(self) -> Generator[None, None, None]:
self.scopes.append(Scope())
try:
yield
finally:
self.previous_scopes.append(self.scopes.pop())
def _file_line(self, filename: str, line: int) -> FileLine:
return FileLine(f'{filename}:{line}')
def definition_str(self, node: ast.AST) -> FileLine:
return self._file_line(self.filename, node.lineno)
def define(self, name: str, node: ast.AST) -> None:
if not self.is_test:
self.scopes[-1].defines[name].add(self.definition_str(node))
def read(self, name: str, node: ast.AST) -> None:
for scope in self.scopes:
if self.is_test:
scope.reads_tests[name].add(self.definition_str(node))
else:
scope.reads[name].add(self.definition_str(node))
def visit_ImportFrom(self, node: ast.ImportFrom) -> None:
for name in node.names:
self.read(name.name, node)
if name.asname:
self.define(name.asname, node)
self.generic_visit(node)
def visit_ClassDef(self, node: ast.ClassDef) -> None:
self.define(node.name, node)
self.generic_visit(node)
def _is_stub_function(self, node: ast.FunctionDef) -> bool:
for stmt in node.body:
if (
isinstance(stmt, ast.Expr) and
isinstance(stmt.value, (ast.Str, ast.Ellipsis))
):
continue # docstring or ...
elif isinstance(stmt, ast.Pass):
continue # pass
elif (
isinstance(stmt, ast.Raise) and
stmt.cause is None and (
(
isinstance(stmt.exc, ast.Name) and
stmt.exc.id in STUB_EXCEPTIONS
) or (
isinstance(stmt.exc, ast.Call) and
isinstance(stmt.exc.func, ast.Name) and
stmt.exc.func.id in STUB_EXCEPTIONS
)
)
):
continue # raise NotImplementedError
else:
return False
else:
return True
def visit_FunctionDef(self, node: ast.FunctionDef) -> None:
self.define(node.name, node)
with self.scope():
if not self._is_stub_function(node):
for arg in (
*getattr(node.args, 'posonlyargs', ()),
*node.args.args,
node.args.vararg,
*node.args.kwonlyargs,
node.args.kwarg,
):
if arg is not None:
self.define(arg.arg, arg)
self.generic_visit(node)
visit_AsyncFunctionDef = visit_FunctionDef
def visit_Assign(self, node: ast.Assign) -> None:
for target in node.targets:
if isinstance(target, ast.Name):
self.define(target.id, node)
if (
len(node.targets) == 1 and
isinstance(node.targets[0], ast.Name) and
node.targets[0].id == '__all__' and
isinstance(node.value, (ast.Tuple, ast.List))
):
for elt in node.value.elts:
if isinstance(elt, ast.Str):
self.read(elt.s, elt)
self.generic_visit(node)
# TODO: AnnAssign
def visit_Name(self, node: ast.Name) -> None:
if isinstance(node.ctx, ast.Load):
self.read(node.id, node)
self.generic_visit(node)
def visit_Attribute(self, node: ast.Attribute) -> None:
if isinstance(node.ctx, ast.Load):
self.read(node.attr, node)
self.generic_visit(node)
def visit_comment(self, lineno: int, line: str) -> None:
if DISABLE_COMMENT_RE.search(line):
self.disabled.add(self._file_line(self.filename, lineno))
if not TYPE_COMMENT_RE.match(line) or TYPE_IGNORE_RE.match(line):
return
line = line.split(':', 1)[1].strip()
func_match = TYPE_FUNC_RE.match(line)
if not func_match:
parts: Tuple[str, ...] = (line,)
else:
parts = (
func_match.group(1).replace('*', ''),
func_match.group(2).strip(),
)
for part in parts:
ast_obj = ast.parse(part, f'<{self.filename}:{lineno}: comment>')
# adjust the line number to be that of the comment
for descendant in ast.walk(ast_obj):
if 'lineno' in descendant._attributes:
descendant.lineno = lineno
self.visit(ast_obj)
def _filenames(
files_re: Pattern[str],
exclude_re: Pattern[str],
tests_re: Pattern[str],
) -> Generator[Tuple[str, bool], None, None]:
# TODO: zsplit is more correct than splitlines
out = subprocess.check_output(('git', 'ls-files')).decode()
for filename in out.splitlines():
if (
not files_re.search(filename) or
exclude_re.search(filename) or
not os.path.exists(filename) or
'python' not in tags_from_path(filename)
):
continue
yield filename, bool(tests_re.search(filename))
def _ast(filename: str) -> ast.AST:
with open(filename, 'rb') as f:
return ast.parse(f.read(), filename=filename)
ENTRYPOINT_RE = re.compile('^[^=]+=[^:]+:([a-zA-Z0-9_]+)$')
class ParsesEntryPoints(ast.NodeVisitor):
"""Mark entry_points attributes as used"""
def __init__(self, visitor: Visitor) -> None:
self.visitor = visitor
def visit_Str(self, node: ast.Str) -> None:
match = ENTRYPOINT_RE.match(node.s)
if match:
self.visitor.read(match.group(1), node)
self.generic_visit(node)
def parse_entry_points_setup_py(visitor: Visitor) -> None:
if not os.path.exists('setup.py'):
return
with visitor.file_ctx('setup.py', is_test=False):
ParsesEntryPoints(visitor).visit(_ast('setup.py'))
def parse_entry_points_setup_cfg(visitor: Visitor) -> None:
if not os.path.exists('setup.cfg'):
return
with visitor.file_ctx('setup.cfg', is_test=False):
parser = configparser.ConfigParser()
parser.read('setup.cfg')
if 'options.entry_points' not in parser:
return
section = parser['options.entry_points']
for k, v in section.items():
for line in v.strip().splitlines():
match = ENTRYPOINT_RE.match(line)
if match:
node = ast.fix_missing_locations(ast.Str(match.group(1)))
visitor.read(match.group(1), node)
def main(argv: Optional[Sequence[str]] = None) -> int:
parser = argparse.ArgumentParser()
parser.add_argument(
'--files', default='',
help='regex for file inclusion, default: %(default)r',
)
parser.add_argument(
'--exclude', default='^$',
help='regex for file exclusion, default %(default)r',
)
parser.add_argument(
'--tests', default='(^|/)(tests?|testing)/',
help='regex to mark files as tests, default %(default)r',
)
args = parser.parse_args(argv)
# TODO:
#
# class FooEnum(Enum):
# BAR = 1 # if not referenced directly, hunter assumes unused
#
# for f in FooEnum: # actually a reference to BAR
# ...
# TODO: v common for methods to only exist to satisfy interface
visitor = Visitor()
parse_entry_points_setup_py(visitor)
parse_entry_points_setup_cfg(visitor)
files_re = re.compile(args.files)
exclude_re = re.compile(args.exclude)
tests_re = re.compile(args.tests)
for filename, is_test in _filenames(files_re, exclude_re, tests_re):
tree = _ast(filename)
with visitor.file_ctx(filename, is_test=is_test):
visitor.visit(tree)
with open(filename, 'rb') as f:
for tp, s, (lineno, _), _, _ in tokenize.tokenize(f.readline):
if tp == tokenize.COMMENT:
visitor.visit_comment(lineno, s)
retv = 0
visitor.previous_scopes.append(visitor.scopes.pop())
unused_ignores = visitor.disabled.copy()
for scope in visitor.previous_scopes:
for k, v in scope.defines.items():
if k not in scope.reads:
unused_ignores.difference_update(v)
v = v - visitor.disabled
if k.startswith('__') and k.endswith('__'):
pass # skip magic methods, probably an interface
elif k in {'cls', 'self'}:
pass # ignore conventional cls / self
elif k not in scope.reads and not v:
pass # all references disabled
elif k not in scope.reads and k not in scope.reads_tests:
print(f'{k} is never read, defined in {", ".join(sorted(v))}')
retv = 1
elif k not in scope.reads:
print(
f'{k} is only referenced in tests, '
f'defined in {", ".join(sorted(v))}',
)
retv = 1
if unused_ignores:
for ignore in sorted(unused_ignores):
print(f'{ignore}: unused `# dead: disable`')
retv = 1
return retv
if __name__ == '__main__':
exit(main())
