Files
RustPython/extra_tests/snippets/stdlib_ast.py

91 lines
2.2 KiB
Python

import ast
print(ast)
source = """
def foo():
print('bar')
pass
"""
n = ast.parse(source)
print(n)
print(n.body)
print(n.body[0].name)
assert n.body[0].name == "foo"
foo = n.body[0]
assert foo.lineno == 2
print(foo.body)
assert len(foo.body) == 2
print(foo.body[0])
print(foo.body[0].value.func.id)
assert foo.body[0].value.func.id == "print"
assert foo.body[0].lineno == 3
assert foo.body[1].lineno == 4
n = ast.parse("3 < 4 > 5\n")
assert n.body[0].value.left.value == 3
assert "Lt" in str(n.body[0].value.ops[0])
assert "Gt" in str(n.body[0].value.ops[1])
assert n.body[0].value.comparators[0].value == 4
assert n.body[0].value.comparators[1].value == 5
n = ast.parse("from ... import a\n")
print(n)
i = n.body[0]
assert i.level == 3
assert i.module is None
assert i.names[0].name == "a"
assert i.names[0].asname is None
# Regression test for issue #4862:
# A cyclic AST fed to compile() used to overflow the Rust stack and SIGSEGV.
# After the fix, the recursion guard in ast_from_object raises RecursionError,
# matching CPython's behavior. Covers both Box<T> descents (UnaryOp, BinOp,
# Call, Attribute) and Vec<T> descents (List, Tuple).
import warnings
def _cyclic_cases():
# Box<Expr> descents
u = ast.UnaryOp(op=ast.Not(), lineno=0, col_offset=0)
u.operand = u
yield "UnaryOp", u
b = ast.BinOp(
op=ast.Add(),
right=ast.Constant(value=0, lineno=0, col_offset=0),
lineno=0,
col_offset=0,
)
b.left = b
yield "BinOp", b
c = ast.Call(args=[], keywords=[], lineno=0, col_offset=0)
c.func = c
yield "Call", c
a = ast.Attribute(attr="x", ctx=ast.Load(), lineno=0, col_offset=0)
a.value = a
yield "Attribute", a
# Vec<Expr> descents
lst = ast.List(ctx=ast.Load(), lineno=0, col_offset=0)
lst.elts = [lst]
yield "List", lst
tup = ast.Tuple(ctx=ast.Load(), lineno=0, col_offset=0)
tup.elts = [tup]
yield "Tuple", tup
with warnings.catch_warnings():
warnings.simplefilter("ignore")
for name, node in _cyclic_cases():
try:
compile(ast.Expression(node), "<cyclic>", "eval")
raise AssertionError(f"cyclic {name} should raise RecursionError")
except RecursionError:
pass # expected; matches CPython