import dis import math import os import unittest import sys import _ast import tempfile import types from test import support from test.support import script_helper, FakePath class TestSpecifics(unittest.TestCase): def compile_single(self, source): compile(source, "", "single") def assertInvalidSingle(self, source): self.assertRaises(SyntaxError, self.compile_single, source) def test_no_ending_newline(self): compile("hi", "", "exec") compile("hi\r", "", "exec") def test_empty(self): compile("", "", "exec") def test_other_newlines(self): compile("\r\n", "", "exec") compile("\r", "", "exec") compile("hi\r\nstuff\r\ndef f():\n pass\r", "", "exec") compile("this_is\rreally_old_mac\rdef f():\n pass", "", "exec") def test_debug_assignment(self): # catch assignments to __debug__ self.assertRaises(SyntaxError, compile, '__debug__ = 1', '?', 'single') import builtins prev = builtins.__debug__ setattr(builtins, '__debug__', 'sure') self.assertEqual(__debug__, prev) setattr(builtins, '__debug__', prev) def test_argument_handling(self): # detect duplicate positional and keyword arguments self.assertRaises(SyntaxError, eval, 'lambda a,a:0') self.assertRaises(SyntaxError, eval, 'lambda a,a=1:0') self.assertRaises(SyntaxError, eval, 'lambda a=1,a=1:0') self.assertRaises(SyntaxError, exec, 'def f(a, a): pass') self.assertRaises(SyntaxError, exec, 'def f(a = 0, a = 1): pass') self.assertRaises(SyntaxError, exec, 'def f(a): global a; a = 1') def test_syntax_error(self): self.assertRaises(SyntaxError, compile, "1+*3", "filename", "exec") def test_none_keyword_arg(self): self.assertRaises(SyntaxError, compile, "f(None=1)", "", "exec") def test_duplicate_global_local(self): self.assertRaises(SyntaxError, exec, 'def f(a): global a; a = 1') def test_exec_with_general_mapping_for_locals(self): class M: "Test mapping interface versus possible calls from eval()." def __getitem__(self, key): if key == 'a': return 12 raise KeyError def __setitem__(self, key, value): self.results = (key, value) def keys(self): return list('xyz') m = M() g = globals() exec('z = a', g, m) self.assertEqual(m.results, ('z', 12)) try: exec('z = b', g, m) except NameError: pass else: self.fail('Did not detect a KeyError') exec('z = dir()', g, m) self.assertEqual(m.results, ('z', list('xyz'))) exec('z = globals()', g, m) self.assertEqual(m.results, ('z', g)) exec('z = locals()', g, m) self.assertEqual(m.results, ('z', m)) self.assertRaises(TypeError, exec, 'z = b', m) class A: "Non-mapping" pass m = A() self.assertRaises(TypeError, exec, 'z = a', g, m) # Verify that dict subclasses work as well class D(dict): def __getitem__(self, key): if key == 'a': return 12 return dict.__getitem__(self, key) d = D() exec('z = a', g, d) self.assertEqual(d['z'], 12) def test_extended_arg(self): longexpr = 'x = x or ' + '-x' * 2500 g = {} code = ''' def f(x): %s %s %s %s %s %s %s %s %s %s # the expressions above have no effect, x == argument while x: x -= 1 # EXTENDED_ARG/JUMP_ABSOLUTE here return x ''' % ((longexpr,)*10) exec(code, g) self.assertEqual(g['f'](5), 0) def test_argument_order(self): self.assertRaises(SyntaxError, exec, 'def f(a=1, b): pass') def test_float_literals(self): # testing bad float literals self.assertRaises(SyntaxError, eval, "2e") self.assertRaises(SyntaxError, eval, "2.0e+") self.assertRaises(SyntaxError, eval, "1e-") self.assertRaises(SyntaxError, eval, "3-4e/21") def test_indentation(self): # testing compile() of indented block w/o trailing newline" s = """ if 1: if 2: pass""" compile(s, "", "exec") # This test is probably specific to CPython and may not generalize # to other implementations. We are trying to ensure that when # the first line of code starts after 256, correct line numbers # in tracebacks are still produced. def test_leading_newlines(self): s256 = "".join(["\n"] * 256 + ["spam"]) co = compile(s256, 'fn', 'exec') self.assertEqual(co.co_firstlineno, 257) self.assertEqual(co.co_lnotab, bytes()) def test_literals_with_leading_zeroes(self): for arg in ["077787", "0xj", "0x.", "0e", "090000000000000", "080000000000000", "000000000000009", "000000000000008", "0b42", "0BADCAFE", "0o123456789", "0b1.1", "0o4.2", "0b101j2", "0o153j2", "0b100e1", "0o777e1", "0777", "000777", "000000000000007"]: self.assertRaises(SyntaxError, eval, arg) self.assertEqual(eval("0xff"), 255) self.assertEqual(eval("0777."), 777) self.assertEqual(eval("0777.0"), 777) self.assertEqual(eval("000000000000000000000000000000000000000000000000000777e0"), 777) self.assertEqual(eval("0777e1"), 7770) self.assertEqual(eval("0e0"), 0) self.assertEqual(eval("0000e-012"), 0) self.assertEqual(eval("09.5"), 9.5) self.assertEqual(eval("0777j"), 777j) self.assertEqual(eval("000"), 0) self.assertEqual(eval("00j"), 0j) self.assertEqual(eval("00.0"), 0) self.assertEqual(eval("0e3"), 0) self.assertEqual(eval("090000000000000."), 90000000000000.) self.assertEqual(eval("090000000000000.0000000000000000000000"), 90000000000000.) self.assertEqual(eval("090000000000000e0"), 90000000000000.) self.assertEqual(eval("090000000000000e-0"), 90000000000000.) self.assertEqual(eval("090000000000000j"), 90000000000000j) self.assertEqual(eval("000000000000008."), 8.) self.assertEqual(eval("000000000000009."), 9.) self.assertEqual(eval("0b101010"), 42) self.assertEqual(eval("-0b000000000010"), -2) self.assertEqual(eval("0o777"), 511) self.assertEqual(eval("-0o0000010"), -8) def test_unary_minus(self): # Verify treatment of unary minus on negative numbers SF bug #660455 if sys.maxsize == 2147483647: # 32-bit machine all_one_bits = '0xffffffff' self.assertEqual(eval(all_one_bits), 4294967295) self.assertEqual(eval("-" + all_one_bits), -4294967295) elif sys.maxsize == 9223372036854775807: # 64-bit machine all_one_bits = '0xffffffffffffffff' self.assertEqual(eval(all_one_bits), 18446744073709551615) self.assertEqual(eval("-" + all_one_bits), -18446744073709551615) else: self.fail("How many bits *does* this machine have???") # Verify treatment of constant folding on -(sys.maxsize+1) # i.e. -2147483648 on 32 bit platforms. Should return int. self.assertIsInstance(eval("%s" % (-sys.maxsize - 1)), int) self.assertIsInstance(eval("%s" % (-sys.maxsize - 2)), int) if sys.maxsize == 9223372036854775807: def test_32_63_bit_values(self): a = +4294967296 # 1 << 32 b = -4294967296 # 1 << 32 c = +281474976710656 # 1 << 48 d = -281474976710656 # 1 << 48 e = +4611686018427387904 # 1 << 62 f = -4611686018427387904 # 1 << 62 g = +9223372036854775807 # 1 << 63 - 1 h = -9223372036854775807 # 1 << 63 - 1 for variable in self.test_32_63_bit_values.__code__.co_consts: if variable is not None: self.assertIsInstance(variable, int) def test_sequence_unpacking_error(self): # Verify sequence packing/unpacking with "or". SF bug #757818 i,j = (1, -1) or (-1, 1) self.assertEqual(i, 1) self.assertEqual(j, -1) def test_none_assignment(self): stmts = [ 'None = 0', 'None += 0', '__builtins__.None = 0', 'def None(): pass', 'class None: pass', '(a, None) = 0, 0', 'for None in range(10): pass', 'def f(None): pass', 'import None', 'import x as None', 'from x import None', 'from x import y as None' ] for stmt in stmts: stmt += "\n" self.assertRaises(SyntaxError, compile, stmt, 'tmp', 'single') self.assertRaises(SyntaxError, compile, stmt, 'tmp', 'exec') def test_import(self): succeed = [ 'import sys', 'import os, sys', 'import os as bar', 'import os.path as bar', 'from __future__ import nested_scopes, generators', 'from __future__ import (nested_scopes,\ngenerators)', 'from __future__ import (nested_scopes,\ngenerators,)', 'from sys import stdin, stderr, stdout', 'from sys import (stdin, stderr,\nstdout)', 'from sys import (stdin, stderr,\nstdout,)', 'from sys import (stdin\n, stderr, stdout)', 'from sys import (stdin\n, stderr, stdout,)', 'from sys import stdin as si, stdout as so, stderr as se', 'from sys import (stdin as si, stdout as so, stderr as se)', 'from sys import (stdin as si, stdout as so, stderr as se,)', ] fail = [ 'import (os, sys)', 'import (os), (sys)', 'import ((os), (sys))', 'import (sys', 'import sys)', 'import (os,)', 'import os As bar', 'import os.path a bar', 'from sys import stdin As stdout', 'from sys import stdin a stdout', 'from (sys) import stdin', 'from __future__ import (nested_scopes', 'from __future__ import nested_scopes)', 'from __future__ import nested_scopes,\ngenerators', 'from sys import (stdin', 'from sys import stdin)', 'from sys import stdin, stdout,\nstderr', 'from sys import stdin si', 'from sys import stdin,', 'from sys import (*)', 'from sys import (stdin,, stdout, stderr)', 'from sys import (stdin, stdout),', ] for stmt in succeed: compile(stmt, 'tmp', 'exec') for stmt in fail: self.assertRaises(SyntaxError, compile, stmt, 'tmp', 'exec') def test_for_distinct_code_objects(self): # SF bug 1048870 def f(): f1 = lambda x=1: x f2 = lambda x=2: x return f1, f2 f1, f2 = f() self.assertNotEqual(id(f1.__code__), id(f2.__code__)) def test_lambda_doc(self): l = lambda: "foo" self.assertIsNone(l.__doc__) def test_encoding(self): code = b'# -*- coding: badencoding -*-\npass\n' self.assertRaises(SyntaxError, compile, code, 'tmp', 'exec') code = '# -*- coding: badencoding -*-\n"\xc2\xa4"\n' compile(code, 'tmp', 'exec') self.assertEqual(eval(code), '\xc2\xa4') code = '"\xc2\xa4"\n' self.assertEqual(eval(code), '\xc2\xa4') code = b'"\xc2\xa4"\n' self.assertEqual(eval(code), '\xa4') code = b'# -*- coding: latin1 -*-\n"\xc2\xa4"\n' self.assertEqual(eval(code), '\xc2\xa4') code = b'# -*- coding: utf-8 -*-\n"\xc2\xa4"\n' self.assertEqual(eval(code), '\xa4') code = b'# -*- coding: iso8859-15 -*-\n"\xc2\xa4"\n' self.assertEqual(eval(code), '\xc2\u20ac') code = '"""\\\n# -*- coding: iso8859-15 -*-\n\xc2\xa4"""\n' self.assertEqual(eval(code), '# -*- coding: iso8859-15 -*-\n\xc2\xa4') code = b'"""\\\n# -*- coding: iso8859-15 -*-\n\xc2\xa4"""\n' self.assertEqual(eval(code), '# -*- coding: iso8859-15 -*-\n\xa4') def test_subscripts(self): # SF bug 1448804 # Class to make testing subscript results easy class str_map(object): def __init__(self): self.data = {} def __getitem__(self, key): return self.data[str(key)] def __setitem__(self, key, value): self.data[str(key)] = value def __delitem__(self, key): del self.data[str(key)] def __contains__(self, key): return str(key) in self.data d = str_map() # Index d[1] = 1 self.assertEqual(d[1], 1) d[1] += 1 self.assertEqual(d[1], 2) del d[1] self.assertNotIn(1, d) # Tuple of indices d[1, 1] = 1 self.assertEqual(d[1, 1], 1) d[1, 1] += 1 self.assertEqual(d[1, 1], 2) del d[1, 1] self.assertNotIn((1, 1), d) # Simple slice d[1:2] = 1 self.assertEqual(d[1:2], 1) d[1:2] += 1 self.assertEqual(d[1:2], 2) del d[1:2] self.assertNotIn(slice(1, 2), d) # Tuple of simple slices d[1:2, 1:2] = 1 self.assertEqual(d[1:2, 1:2], 1) d[1:2, 1:2] += 1 self.assertEqual(d[1:2, 1:2], 2) del d[1:2, 1:2] self.assertNotIn((slice(1, 2), slice(1, 2)), d) # Extended slice d[1:2:3] = 1 self.assertEqual(d[1:2:3], 1) d[1:2:3] += 1 self.assertEqual(d[1:2:3], 2) del d[1:2:3] self.assertNotIn(slice(1, 2, 3), d) # Tuple of extended slices d[1:2:3, 1:2:3] = 1 self.assertEqual(d[1:2:3, 1:2:3], 1) d[1:2:3, 1:2:3] += 1 self.assertEqual(d[1:2:3, 1:2:3], 2) del d[1:2:3, 1:2:3] self.assertNotIn((slice(1, 2, 3), slice(1, 2, 3)), d) # Ellipsis d[...] = 1 self.assertEqual(d[...], 1) d[...] += 1 self.assertEqual(d[...], 2) del d[...] self.assertNotIn(Ellipsis, d) # Tuple of Ellipses d[..., ...] = 1 self.assertEqual(d[..., ...], 1) d[..., ...] += 1 self.assertEqual(d[..., ...], 2) del d[..., ...] self.assertNotIn((Ellipsis, Ellipsis), d) def test_annotation_limit(self): # more than 255 annotations, should compile ok s = "def f(%s): pass" s %= ', '.join('a%d:%d' % (i,i) for i in range(300)) compile(s, '?', 'exec') def test_mangling(self): class A: def f(): __mangled = 1 __not_mangled__ = 2 import __mangled_mod import __package__.module self.assertIn("_A__mangled", A.f.__code__.co_varnames) self.assertIn("__not_mangled__", A.f.__code__.co_varnames) self.assertIn("_A__mangled_mod", A.f.__code__.co_varnames) self.assertIn("__package__", A.f.__code__.co_varnames) def test_compile_ast(self): fname = __file__ if fname.lower().endswith('pyc'): fname = fname[:-1] with open(fname, 'r') as f: fcontents = f.read() sample_code = [ ['', 'x = 5'], ['', """if True:\n pass\n"""], ['', """for n in [1, 2, 3]:\n print(n)\n"""], ['', """def foo():\n pass\nfoo()\n"""], [fname, fcontents], ] for fname, code in sample_code: co1 = compile(code, '%s1' % fname, 'exec') ast = compile(code, '%s2' % fname, 'exec', _ast.PyCF_ONLY_AST) self.assertTrue(type(ast) == _ast.Module) co2 = compile(ast, '%s3' % fname, 'exec') self.assertEqual(co1, co2) # the code object's filename comes from the second compilation step self.assertEqual(co2.co_filename, '%s3' % fname) # raise exception when node type doesn't match with compile mode co1 = compile('print(1)', '', 'exec', _ast.PyCF_ONLY_AST) self.assertRaises(TypeError, compile, co1, '', 'eval') # raise exception when node type is no start node self.assertRaises(TypeError, compile, _ast.If(), '', 'exec') # raise exception when node has invalid children ast = _ast.Module() ast.body = [_ast.BoolOp()] self.assertRaises(TypeError, compile, ast, '', 'exec') def test_dict_evaluation_order(self): i = 0 def f(): nonlocal i i += 1 return i d = {f(): f(), f(): f()} self.assertEqual(d, {1: 2, 3: 4}) def test_compile_filename(self): for filename in 'file.py', b'file.py': code = compile('pass', filename, 'exec') self.assertEqual(code.co_filename, 'file.py') for filename in bytearray(b'file.py'), memoryview(b'file.py'): with self.assertWarns(DeprecationWarning): code = compile('pass', filename, 'exec') self.assertEqual(code.co_filename, 'file.py') self.assertRaises(TypeError, compile, 'pass', list(b'file.py'), 'exec') @support.cpython_only def test_same_filename_used(self): s = """def f(): pass\ndef g(): pass""" c = compile(s, "myfile", "exec") for obj in c.co_consts: if isinstance(obj, types.CodeType): self.assertIs(obj.co_filename, c.co_filename) def test_single_statement(self): self.compile_single("1 + 2") self.compile_single("\n1 + 2") self.compile_single("1 + 2\n") self.compile_single("1 + 2\n\n") self.compile_single("1 + 2\t\t\n") self.compile_single("1 + 2\t\t\n ") self.compile_single("1 + 2 # one plus two") self.compile_single("1; 2") self.compile_single("import sys; sys") self.compile_single("def f():\n pass") self.compile_single("while False:\n pass") self.compile_single("if x:\n f(x)") self.compile_single("if x:\n f(x)\nelse:\n g(x)") self.compile_single("class T:\n pass") def test_bad_single_statement(self): self.assertInvalidSingle('1\n2') self.assertInvalidSingle('def f(): pass') self.assertInvalidSingle('a = 13\nb = 187') self.assertInvalidSingle('del x\ndel y') self.assertInvalidSingle('f()\ng()') self.assertInvalidSingle('f()\n# blah\nblah()') self.assertInvalidSingle('f()\nxy # blah\nblah()') self.assertInvalidSingle('x = 5 # comment\nx = 6\n') def test_particularly_evil_undecodable(self): # Issue 24022 src = b'0000\x00\n00000000000\n\x00\n\x9e\n' with tempfile.TemporaryDirectory() as tmpd: fn = os.path.join(tmpd, "bad.py") with open(fn, "wb") as fp: fp.write(src) res = script_helper.run_python_until_end(fn)[0] self.assertIn(b"Non-UTF-8", res.err) def test_yet_more_evil_still_undecodable(self): # Issue #25388 src = b"#\x00\n#\xfd\n" with tempfile.TemporaryDirectory() as tmpd: fn = os.path.join(tmpd, "bad.py") with open(fn, "wb") as fp: fp.write(src) res = script_helper.run_python_until_end(fn)[0] self.assertIn(b"Non-UTF-8", res.err) @support.cpython_only def test_compiler_recursion_limit(self): # Expected limit is sys.getrecursionlimit() * the scaling factor # in symtable.c (currently 3) # We expect to fail *at* that limit, because we use up some of # the stack depth limit in the test suite code # So we check the expected limit and 75% of that # XXX (ncoghlan): duplicating the scaling factor here is a little # ugly. Perhaps it should be exposed somewhere... fail_depth = sys.getrecursionlimit() * 3 success_depth = int(fail_depth * 0.75) def check_limit(prefix, repeated): expect_ok = prefix + repeated * success_depth self.compile_single(expect_ok) broken = prefix + repeated * fail_depth details = "Compiling ({!r} + {!r} * {})".format( prefix, repeated, fail_depth) with self.assertRaises(RecursionError, msg=details): self.compile_single(broken) check_limit("a", "()") check_limit("a", ".b") check_limit("a", "[0]") check_limit("a", "*a") def test_null_terminated(self): # The source code is null-terminated internally, but bytes-like # objects are accepted, which could be not terminated. with self.assertRaisesRegex(ValueError, "cannot contain null"): compile("123\x00", "", "eval") with self.assertRaisesRegex(ValueError, "cannot contain null"): compile(memoryview(b"123\x00"), "", "eval") code = compile(memoryview(b"123\x00")[1:-1], "", "eval") self.assertEqual(eval(code), 23) code = compile(memoryview(b"1234")[1:-1], "", "eval") self.assertEqual(eval(code), 23) code = compile(memoryview(b"$23$")[1:-1], "", "eval") self.assertEqual(eval(code), 23) # Also test when eval() and exec() do the compilation step self.assertEqual(eval(memoryview(b"1234")[1:-1]), 23) namespace = dict() exec(memoryview(b"ax = 123")[1:-1], namespace) self.assertEqual(namespace['x'], 12) def check_constant(self, func, expected): for const in func.__code__.co_consts: if repr(const) == repr(expected): break else: self.fail("unable to find constant %r in %r" % (expected, func.__code__.co_consts)) # Merging equal constants is not a strict requirement for the Python # semantics, it's a more an implementation detail. @support.cpython_only def test_merge_constants(self): # Issue #25843: compile() must merge constants which are equal # and have the same type. def check_same_constant(const): ns = {} code = "f1, f2 = lambda: %r, lambda: %r" % (const, const) exec(code, ns) f1 = ns['f1'] f2 = ns['f2'] self.assertIs(f1.__code__, f2.__code__) self.check_constant(f1, const) self.assertEqual(repr(f1()), repr(const)) check_same_constant(None) check_same_constant(0) check_same_constant(0.0) check_same_constant(b'abc') check_same_constant('abc') # Note: "lambda: ..." emits "LOAD_CONST Ellipsis", # whereas "lambda: Ellipsis" emits "LOAD_GLOBAL Ellipsis" f1, f2 = lambda: ..., lambda: ... self.assertIs(f1.__code__, f2.__code__) self.check_constant(f1, Ellipsis) self.assertEqual(repr(f1()), repr(Ellipsis)) # Merge constants in tuple or frozenset f1, f2 = lambda: "not a name", lambda: ("not a name",) f3 = lambda x: x in {("not a name",)} self.assertIs(f1.__code__.co_consts[1], f2.__code__.co_consts[1][0]) self.assertIs(next(iter(f3.__code__.co_consts[1])), f2.__code__.co_consts[1]) # {0} is converted to a constant frozenset({0}) by the peephole # optimizer f1, f2 = lambda x: x in {0}, lambda x: x in {0} self.assertIs(f1.__code__, f2.__code__) self.check_constant(f1, frozenset({0})) self.assertTrue(f1(0)) # This is a regression test for a CPython specific peephole optimizer # implementation bug present in a few releases. It's assertion verifies # that peephole optimization was actually done though that isn't an # indication of the bugs presence or not (crashing is). @support.cpython_only def test_peephole_opt_unreachable_code_array_access_in_bounds(self): """Regression test for issue35193 when run under clang msan.""" def unused_code_at_end(): return 3 raise RuntimeError("unreachable") # The above function definition will trigger the out of bounds # bug in the peephole optimizer as it scans opcodes past the # RETURN_VALUE opcode. This does not always crash an interpreter. # When you build with the clang memory sanitizer it reliably aborts. self.assertEqual( 'RETURN_VALUE', list(dis.get_instructions(unused_code_at_end))[-1].opname) def test_dont_merge_constants(self): # Issue #25843: compile() must not merge constants which are equal # but have a different type. def check_different_constants(const1, const2): ns = {} exec("f1, f2 = lambda: %r, lambda: %r" % (const1, const2), ns) f1 = ns['f1'] f2 = ns['f2'] self.assertIsNot(f1.__code__, f2.__code__) self.assertNotEqual(f1.__code__, f2.__code__) self.check_constant(f1, const1) self.check_constant(f2, const2) self.assertEqual(repr(f1()), repr(const1)) self.assertEqual(repr(f2()), repr(const2)) check_different_constants(0, 0.0) check_different_constants(+0.0, -0.0) check_different_constants((0,), (0.0,)) check_different_constants('a', b'a') check_different_constants(('a',), (b'a',)) # check_different_constants() cannot be used because repr(-0j) is # '(-0-0j)', but when '(-0-0j)' is evaluated to 0j: we loose the sign. f1, f2 = lambda: +0.0j, lambda: -0.0j self.assertIsNot(f1.__code__, f2.__code__) self.check_constant(f1, +0.0j) self.check_constant(f2, -0.0j) self.assertEqual(repr(f1()), repr(+0.0j)) self.assertEqual(repr(f2()), repr(-0.0j)) # {0} is converted to a constant frozenset({0}) by the peephole # optimizer f1, f2 = lambda x: x in {0}, lambda x: x in {0.0} self.assertIsNot(f1.__code__, f2.__code__) self.check_constant(f1, frozenset({0})) self.check_constant(f2, frozenset({0.0})) self.assertTrue(f1(0)) self.assertTrue(f2(0.0)) def test_path_like_objects(self): # An implicit test for PyUnicode_FSDecoder(). compile("42", FakePath("test_compile_pathlike"), "single") def test_stack_overflow(self): # bpo-31113: Stack overflow when compile a long sequence of # complex statements. compile("if a: b\n" * 200000, "", "exec") # Multiple users rely on the fact that CPython does not generate # bytecode for dead code blocks. See bpo-37500 for more context. @support.cpython_only def test_dead_blocks_do_not_generate_bytecode(self): def unused_block_if(): if 0: return 42 def unused_block_while(): while 0: return 42 def unused_block_if_else(): if 1: return None else: return 42 def unused_block_while_else(): while 1: return None else: return 42 funcs = [unused_block_if, unused_block_while, unused_block_if_else, unused_block_while_else] for func in funcs: opcodes = list(dis.get_instructions(func)) self.assertEqual(2, len(opcodes)) self.assertEqual('LOAD_CONST', opcodes[0].opname) self.assertEqual(None, opcodes[0].argval) self.assertEqual('RETURN_VALUE', opcodes[1].opname) class TestExpressionStackSize(unittest.TestCase): # These tests check that the computed stack size for a code object # stays within reasonable bounds (see issue #21523 for an example # dysfunction). N = 100 def check_stack_size(self, code): # To assert that the alleged stack size is not O(N), we # check that it is smaller than log(N). if isinstance(code, str): code = compile(code, "", "single") max_size = math.ceil(math.log(len(code.co_code))) self.assertLessEqual(code.co_stacksize, max_size) def test_and(self): self.check_stack_size("x and " * self.N + "x") def test_or(self): self.check_stack_size("x or " * self.N + "x") def test_and_or(self): self.check_stack_size("x and x or " * self.N + "x") def test_chained_comparison(self): self.check_stack_size("x < " * self.N + "x") def test_if_else(self): self.check_stack_size("x if x else " * self.N + "x") def test_binop(self): self.check_stack_size("x + " * self.N + "x") def test_func_and(self): code = "def f(x):\n" code += " x and x\n" * self.N self.check_stack_size(code) class TestStackSizeStability(unittest.TestCase): # Check that repeating certain snippets doesn't increase the stack size # beyond what a single snippet requires. def check_stack_size(self, snippet, async_=False): def compile_snippet(i): ns = {} script = """def func():\n""" + i * snippet if async_: script = "async " + script code = compile(script, "