| import doctest |
| import textwrap |
| import types |
| import unittest |
| |
| |
| doctests = """ |
| ########### Tests borrowed from or inspired by test_genexps.py ############ |
| |
| Test simple loop with conditional |
| |
| >>> sum([i*i for i in range(100) if i&1 == 1]) |
| 166650 |
| |
| Test simple nesting |
| |
| >>> [(i,j) for i in range(3) for j in range(4)] |
| [(0, 0), (0, 1), (0, 2), (0, 3), (1, 0), (1, 1), (1, 2), (1, 3), (2, 0), (2, 1), (2, 2), (2, 3)] |
| |
| Test nesting with the inner expression dependent on the outer |
| |
| >>> [(i,j) for i in range(4) for j in range(i)] |
| [(1, 0), (2, 0), (2, 1), (3, 0), (3, 1), (3, 2)] |
| |
| Test the idiom for temporary variable assignment in comprehensions. |
| |
| >>> [j*j for i in range(4) for j in [i+1]] |
| [1, 4, 9, 16] |
| >>> [j*k for i in range(4) for j in [i+1] for k in [j+1]] |
| [2, 6, 12, 20] |
| >>> [j*k for i in range(4) for j, k in [(i+1, i+2)]] |
| [2, 6, 12, 20] |
| |
| Not assignment |
| |
| >>> [i*i for i in [*range(4)]] |
| [0, 1, 4, 9] |
| >>> [i*i for i in (*range(4),)] |
| [0, 1, 4, 9] |
| |
| Make sure the induction variable is not exposed |
| |
| >>> i = 20 |
| >>> sum([i*i for i in range(100)]) |
| 328350 |
| |
| >>> i |
| 20 |
| |
| Verify that syntax error's are raised for listcomps used as lvalues |
| |
| >>> [y for y in (1,2)] = 10 # doctest: +IGNORE_EXCEPTION_DETAIL |
| Traceback (most recent call last): |
| ... |
| SyntaxError: ... |
| |
| >>> [y for y in (1,2)] += 10 # doctest: +IGNORE_EXCEPTION_DETAIL |
| Traceback (most recent call last): |
| ... |
| SyntaxError: ... |
| |
| |
| ########### Tests borrowed from or inspired by test_generators.py ############ |
| |
| Make a nested list comprehension that acts like range() |
| |
| >>> def frange(n): |
| ... return [i for i in range(n)] |
| >>> frange(10) |
| [0, 1, 2, 3, 4, 5, 6, 7, 8, 9] |
| |
| Same again, only as a lambda expression instead of a function definition |
| |
| >>> lrange = lambda n: [i for i in range(n)] |
| >>> lrange(10) |
| [0, 1, 2, 3, 4, 5, 6, 7, 8, 9] |
| |
| Generators can call other generators: |
| |
| >>> def grange(n): |
| ... for x in [i for i in range(n)]: |
| ... yield x |
| >>> list(grange(5)) |
| [0, 1, 2, 3, 4] |
| |
| |
| Make sure that None is a valid return value |
| |
| >>> [None for i in range(10)] |
| [None, None, None, None, None, None, None, None, None, None] |
| |
| """ |
| |
| |
| class ListComprehensionTest(unittest.TestCase): |
| def _check_in_scopes(self, code, outputs=None, ns=None, scopes=None, raises=(), |
| exec_func=exec): |
| code = textwrap.dedent(code) |
| scopes = scopes or ["module", "class", "function"] |
| for scope in scopes: |
| with self.subTest(scope=scope): |
| if scope == "class": |
| newcode = textwrap.dedent(""" |
| class _C: |
| {code} |
| """).format(code=textwrap.indent(code, " ")) |
| def get_output(moddict, name): |
| return getattr(moddict["_C"], name) |
| elif scope == "function": |
| newcode = textwrap.dedent(""" |
| def _f(): |
| {code} |
| return locals() |
| _out = _f() |
| """).format(code=textwrap.indent(code, " ")) |
| def get_output(moddict, name): |
| return moddict["_out"][name] |
| else: |
| newcode = code |
| def get_output(moddict, name): |
| return moddict[name] |
| newns = ns.copy() if ns else {} |
| try: |
| exec_func(newcode, newns) |
| except raises as e: |
| # We care about e.g. NameError vs UnboundLocalError |
| self.assertIs(type(e), raises) |
| else: |
| for k, v in (outputs or {}).items(): |
| self.assertEqual(get_output(newns, k), v, k) |
| |
| def test_lambdas_with_iteration_var_as_default(self): |
| code = """ |
| items = [(lambda i=i: i) for i in range(5)] |
| y = [x() for x in items] |
| """ |
| outputs = {"y": [0, 1, 2, 3, 4]} |
| self._check_in_scopes(code, outputs) |
| |
| def test_lambdas_with_free_var(self): |
| code = """ |
| items = [(lambda: i) for i in range(5)] |
| y = [x() for x in items] |
| """ |
| outputs = {"y": [4, 4, 4, 4, 4]} |
| self._check_in_scopes(code, outputs) |
| |
| def test_class_scope_free_var_with_class_cell(self): |
| class C: |
| def method(self): |
| super() |
| return __class__ |
| items = [(lambda: i) for i in range(5)] |
| y = [x() for x in items] |
| |
| self.assertEqual(C.y, [4, 4, 4, 4, 4]) |
| self.assertIs(C().method(), C) |
| |
| def test_references_super(self): |
| code = """ |
| res = [super for x in [1]] |
| """ |
| self._check_in_scopes(code, outputs={"res": [super]}) |
| |
| def test_references___class__(self): |
| code = """ |
| res = [__class__ for x in [1]] |
| """ |
| self._check_in_scopes(code, raises=NameError) |
| |
| def test_inner_cell_shadows_outer(self): |
| code = """ |
| items = [(lambda: i) for i in range(5)] |
| i = 20 |
| y = [x() for x in items] |
| """ |
| outputs = {"y": [4, 4, 4, 4, 4], "i": 20} |
| self._check_in_scopes(code, outputs) |
| |
| def test_inner_cell_shadows_outer_no_store(self): |
| code = """ |
| def f(x): |
| return [lambda: x for x in range(x)], x |
| fns, x = f(2) |
| y = [fn() for fn in fns] |
| """ |
| outputs = {"y": [1, 1], "x": 2} |
| self._check_in_scopes(code, outputs) |
| |
| def test_closure_can_jump_over_comp_scope(self): |
| code = """ |
| items = [(lambda: y) for i in range(5)] |
| y = 2 |
| z = [x() for x in items] |
| """ |
| outputs = {"z": [2, 2, 2, 2, 2]} |
| self._check_in_scopes(code, outputs, scopes=["module", "function"]) |
| |
| def test_cell_inner_free_outer(self): |
| code = """ |
| def f(): |
| return [lambda: x for x in (x, [1])[1]] |
| x = ... |
| y = [fn() for fn in f()] |
| """ |
| outputs = {"y": [1]} |
| self._check_in_scopes(code, outputs, scopes=["module", "function"]) |
| |
| def test_free_inner_cell_outer(self): |
| code = """ |
| g = 2 |
| def f(): |
| return g |
| y = [g for x in [1]] |
| """ |
| outputs = {"y": [2]} |
| self._check_in_scopes(code, outputs, scopes=["module", "function"]) |
| self._check_in_scopes(code, scopes=["class"], raises=NameError) |
| |
| def test_inner_cell_shadows_outer_redefined(self): |
| code = """ |
| y = 10 |
| items = [(lambda: y) for y in range(5)] |
| x = y |
| y = 20 |
| out = [z() for z in items] |
| """ |
| outputs = {"x": 10, "out": [4, 4, 4, 4, 4]} |
| self._check_in_scopes(code, outputs) |
| |
| def test_shadows_outer_cell(self): |
| code = """ |
| def inner(): |
| return g |
| [g for g in range(5)] |
| x = inner() |
| """ |
| outputs = {"x": -1} |
| self._check_in_scopes(code, outputs, ns={"g": -1}) |
| |
| def test_explicit_global(self): |
| code = """ |
| global g |
| x = g |
| g = 2 |
| items = [g for g in [1]] |
| y = g |
| """ |
| outputs = {"x": 1, "y": 2, "items": [1]} |
| self._check_in_scopes(code, outputs, ns={"g": 1}) |
| |
| def test_explicit_global_2(self): |
| code = """ |
| global g |
| x = g |
| g = 2 |
| items = [g for x in [1]] |
| y = g |
| """ |
| outputs = {"x": 1, "y": 2, "items": [2]} |
| self._check_in_scopes(code, outputs, ns={"g": 1}) |
| |
| def test_explicit_global_3(self): |
| code = """ |
| global g |
| fns = [lambda: g for g in [2]] |
| items = [fn() for fn in fns] |
| """ |
| outputs = {"items": [2]} |
| self._check_in_scopes(code, outputs, ns={"g": 1}) |
| |
| def test_assignment_expression(self): |
| code = """ |
| x = -1 |
| items = [(x:=y) for y in range(3)] |
| """ |
| outputs = {"x": 2} |
| # assignment expression in comprehension is disallowed in class scope |
| self._check_in_scopes(code, outputs, scopes=["module", "function"]) |
| |
| def test_free_var_in_comp_child(self): |
| code = """ |
| lst = range(3) |
| funcs = [lambda: x for x in lst] |
| inc = [x + 1 for x in lst] |
| [x for x in inc] |
| x = funcs[0]() |
| """ |
| outputs = {"x": 2} |
| self._check_in_scopes(code, outputs) |
| |
| def test_shadow_with_free_and_local(self): |
| code = """ |
| lst = range(3) |
| x = -1 |
| funcs = [lambda: x for x in lst] |
| items = [x + 1 for x in lst] |
| """ |
| outputs = {"x": -1} |
| self._check_in_scopes(code, outputs) |
| |
| def test_shadow_comp_iterable_name(self): |
| code = """ |
| x = [1] |
| y = [x for x in x] |
| """ |
| outputs = {"x": [1]} |
| self._check_in_scopes(code, outputs) |
| |
| def test_nested_free(self): |
| code = """ |
| x = 1 |
| def g(): |
| [x for x in range(3)] |
| return x |
| g() |
| """ |
| outputs = {"x": 1} |
| self._check_in_scopes(code, outputs, scopes=["module", "function"]) |
| |
| def test_introspecting_frame_locals(self): |
| code = """ |
| import sys |
| [i for i in range(2)] |
| i = 20 |
| sys._getframe().f_locals |
| """ |
| outputs = {"i": 20} |
| self._check_in_scopes(code, outputs) |
| |
| def test_nested(self): |
| code = """ |
| l = [2, 3] |
| y = [[x ** 2 for x in range(x)] for x in l] |
| """ |
| outputs = {"y": [[0, 1], [0, 1, 4]]} |
| self._check_in_scopes(code, outputs) |
| |
| def test_nested_2(self): |
| code = """ |
| l = [1, 2, 3] |
| x = 3 |
| y = [x for [x ** x for x in range(x)][x - 1] in l] |
| """ |
| outputs = {"y": [3, 3, 3]} |
| self._check_in_scopes(code, outputs, scopes=["module", "function"]) |
| self._check_in_scopes(code, scopes=["class"], raises=NameError) |
| |
| def test_nested_3(self): |
| code = """ |
| l = [(1, 2), (3, 4), (5, 6)] |
| y = [x for (x, [x ** x for x in range(x)][x - 1]) in l] |
| """ |
| outputs = {"y": [1, 3, 5]} |
| self._check_in_scopes(code, outputs) |
| |
| def test_nested_4(self): |
| code = """ |
| items = [([lambda: x for x in range(2)], lambda: x) for x in range(3)] |
| out = [([fn() for fn in fns], fn()) for fns, fn in items] |
| """ |
| outputs = {"out": [([1, 1], 2), ([1, 1], 2), ([1, 1], 2)]} |
| self._check_in_scopes(code, outputs) |
| |
| def test_nameerror(self): |
| code = """ |
| [x for x in [1]] |
| x |
| """ |
| |
| self._check_in_scopes(code, raises=NameError) |
| |
| def test_dunder_name(self): |
| code = """ |
| y = [__x for __x in [1]] |
| """ |
| outputs = {"y": [1]} |
| self._check_in_scopes(code, outputs) |
| |
| def test_unbound_local_after_comprehension(self): |
| def f(): |
| if False: |
| x = 0 |
| [x for x in [1]] |
| return x |
| |
| with self.assertRaises(UnboundLocalError): |
| f() |
| |
| def test_unbound_local_inside_comprehension(self): |
| def f(): |
| l = [None] |
| return [1 for (l[0], l) in [[1, 2]]] |
| |
| with self.assertRaises(UnboundLocalError): |
| f() |
| |
| def test_global_outside_cellvar_inside_plus_freevar(self): |
| code = """ |
| a = 1 |
| def f(): |
| func, = [(lambda: b) for b in [a]] |
| return b, func() |
| x = f() |
| """ |
| self._check_in_scopes( |
| code, {"x": (2, 1)}, ns={"b": 2}, scopes=["function", "module"]) |
| # inside a class, the `a = 1` assignment is not visible |
| self._check_in_scopes(code, raises=NameError, scopes=["class"]) |
| |
| def test_cell_in_nested_comprehension(self): |
| code = """ |
| a = 1 |
| def f(): |
| (func, inner_b), = [[lambda: b for b in c] + [b] for c in [[a]]] |
| return b, inner_b, func() |
| x = f() |
| """ |
| self._check_in_scopes( |
| code, {"x": (2, 2, 1)}, ns={"b": 2}, scopes=["function", "module"]) |
| # inside a class, the `a = 1` assignment is not visible |
| self._check_in_scopes(code, raises=NameError, scopes=["class"]) |
| |
| def test_name_error_in_class_scope(self): |
| code = """ |
| y = 1 |
| [x + y for x in range(2)] |
| """ |
| self._check_in_scopes(code, raises=NameError, scopes=["class"]) |
| |
| def test_global_in_class_scope(self): |
| code = """ |
| y = 2 |
| vals = [(x, y) for x in range(2)] |
| """ |
| outputs = {"vals": [(0, 1), (1, 1)]} |
| self._check_in_scopes(code, outputs, ns={"y": 1}, scopes=["class"]) |
| |
| def test_in_class_scope_inside_function_1(self): |
| code = """ |
| class C: |
| y = 2 |
| vals = [(x, y) for x in range(2)] |
| vals = C.vals |
| """ |
| outputs = {"vals": [(0, 1), (1, 1)]} |
| self._check_in_scopes(code, outputs, ns={"y": 1}, scopes=["function"]) |
| |
| def test_in_class_scope_inside_function_2(self): |
| code = """ |
| y = 1 |
| class C: |
| y = 2 |
| vals = [(x, y) for x in range(2)] |
| vals = C.vals |
| """ |
| outputs = {"vals": [(0, 1), (1, 1)]} |
| self._check_in_scopes(code, outputs, scopes=["function"]) |
| |
| def test_in_class_scope_with_global(self): |
| code = """ |
| y = 1 |
| class C: |
| global y |
| y = 2 |
| # Ensure the listcomp uses the global, not the value in the |
| # class namespace |
| locals()['y'] = 3 |
| vals = [(x, y) for x in range(2)] |
| vals = C.vals |
| """ |
| outputs = {"vals": [(0, 2), (1, 2)]} |
| self._check_in_scopes(code, outputs, scopes=["module", "class"]) |
| outputs = {"vals": [(0, 1), (1, 1)]} |
| self._check_in_scopes(code, outputs, scopes=["function"]) |
| |
| def test_in_class_scope_with_nonlocal(self): |
| code = """ |
| y = 1 |
| class C: |
| nonlocal y |
| y = 2 |
| # Ensure the listcomp uses the global, not the value in the |
| # class namespace |
| locals()['y'] = 3 |
| vals = [(x, y) for x in range(2)] |
| vals = C.vals |
| """ |
| outputs = {"vals": [(0, 2), (1, 2)]} |
| self._check_in_scopes(code, outputs, scopes=["function"]) |
| |
| def test_nested_has_free_var(self): |
| code = """ |
| items = [a for a in [1] if [a for _ in [0]]] |
| """ |
| outputs = {"items": [1]} |
| self._check_in_scopes(code, outputs, scopes=["class"]) |
| |
| def test_nested_free_var_not_bound_in_outer_comp(self): |
| code = """ |
| z = 1 |
| items = [a for a in [1] if [x for x in [1] if z]] |
| """ |
| self._check_in_scopes(code, {"items": [1]}, scopes=["module", "function"]) |
| self._check_in_scopes(code, {"items": []}, ns={"z": 0}, scopes=["class"]) |
| |
| def test_nested_free_var_in_iter(self): |
| code = """ |
| items = [_C for _C in [1] for [0, 1][[x for x in [1] if _C][0]] in [2]] |
| """ |
| self._check_in_scopes(code, {"items": [1]}) |
| |
| def test_nested_free_var_in_expr(self): |
| code = """ |
| items = [(_C, [x for x in [1] if _C]) for _C in [0, 1]] |
| """ |
| self._check_in_scopes(code, {"items": [(0, []), (1, [1])]}) |
| |
| def test_nested_listcomp_in_lambda(self): |
| code = """ |
| f = [(z, lambda y: [(x, y, z) for x in [3]]) for z in [1]] |
| (z, func), = f |
| out = func(2) |
| """ |
| self._check_in_scopes(code, {"z": 1, "out": [(3, 2, 1)]}) |
| |
| def test_lambda_in_iter(self): |
| code = """ |
| (func, c), = [(a, b) for b in [1] for a in [lambda : a]] |
| d = func() |
| assert d is func |
| # must use "a" in this scope |
| e = a if False else None |
| """ |
| self._check_in_scopes(code, {"c": 1, "e": None}) |
| |
| def test_assign_to_comp_iter_var_in_outer_function(self): |
| code = """ |
| a = [1 for a in [0]] |
| """ |
| self._check_in_scopes(code, {"a": [1]}, scopes=["function"]) |
| |
| def test_no_leakage_to_locals(self): |
| code = """ |
| def b(): |
| [a for b in [1] for _ in []] |
| return b, locals() |
| r, s = b() |
| x = r is b |
| y = list(s.keys()) |
| """ |
| self._check_in_scopes(code, {"x": True, "y": []}, scopes=["module"]) |
| self._check_in_scopes(code, {"x": True, "y": ["b"]}, scopes=["function"]) |
| self._check_in_scopes(code, raises=NameError, scopes=["class"]) |
| |
| def test_iter_var_available_in_locals(self): |
| code = """ |
| l = [1, 2] |
| y = 0 |
| items = [locals()["x"] for x in l] |
| items2 = [vars()["x"] for x in l] |
| items3 = [("x" in dir()) for x in l] |
| items4 = [eval("x") for x in l] |
| # x is available, and does not overwrite y |
| [exec("y = x") for x in l] |
| """ |
| self._check_in_scopes( |
| code, |
| { |
| "items": [1, 2], |
| "items2": [1, 2], |
| "items3": [True, True], |
| "items4": [1, 2], |
| "y": 0 |
| } |
| ) |
| |
| def test_comp_in_try_except(self): |
| template = """ |
| value = ["ab"] |
| result = snapshot = None |
| try: |
| result = [{func}(value) for value in value] |
| except: |
| snapshot = value |
| raise |
| """ |
| # No exception. |
| code = template.format(func='len') |
| self._check_in_scopes(code, {"value": ["ab"], "result": [2], "snapshot": None}) |
| # Handles exception. |
| code = template.format(func='int') |
| self._check_in_scopes(code, {"value": ["ab"], "result": None, "snapshot": ["ab"]}, |
| raises=ValueError) |
| |
| def test_comp_in_try_finally(self): |
| template = """ |
| value = ["ab"] |
| result = snapshot = None |
| try: |
| result = [{func}(value) for value in value] |
| finally: |
| snapshot = value |
| """ |
| # No exception. |
| code = template.format(func='len') |
| self._check_in_scopes(code, {"value": ["ab"], "result": [2], "snapshot": ["ab"]}) |
| # Handles exception. |
| code = template.format(func='int') |
| self._check_in_scopes(code, {"value": ["ab"], "result": None, "snapshot": ["ab"]}, |
| raises=ValueError) |
| |
| def test_exception_in_post_comp_call(self): |
| code = """ |
| value = [1, None] |
| try: |
| [v for v in value].sort() |
| except: |
| pass |
| """ |
| self._check_in_scopes(code, {"value": [1, None]}) |
| |
| def test_frame_locals(self): |
| code = """ |
| val = [sys._getframe().f_locals for a in [0]][0]["a"] |
| """ |
| import sys |
| self._check_in_scopes(code, {"val": 0}, ns={"sys": sys}) |
| |
| def _recursive_replace(self, maybe_code): |
| if not isinstance(maybe_code, types.CodeType): |
| return maybe_code |
| return maybe_code.replace(co_consts=tuple( |
| self._recursive_replace(c) for c in maybe_code.co_consts |
| )) |
| |
| def _replacing_exec(self, code_string, ns): |
| co = compile(code_string, "<string>", "exec") |
| co = self._recursive_replace(co) |
| exec(co, ns) |
| |
| def test_code_replace(self): |
| code = """ |
| x = 3 |
| [x for x in (1, 2)] |
| dir() |
| y = [x] |
| """ |
| self._check_in_scopes(code, {"y": [3], "x": 3}) |
| self._check_in_scopes(code, {"y": [3], "x": 3}, exec_func=self._replacing_exec) |
| |
| def test_code_replace_extended_arg(self): |
| num_names = 300 |
| assignments = "; ".join(f"x{i} = {i}" for i in range(num_names)) |
| name_list = ", ".join(f"x{i}" for i in range(num_names)) |
| expected = { |
| "y": list(range(num_names)), |
| **{f"x{i}": i for i in range(num_names)} |
| } |
| code = f""" |
| {assignments} |
| [({name_list}) for {name_list} in (range(300),)] |
| dir() |
| y = [{name_list}] |
| """ |
| self._check_in_scopes(code, expected) |
| self._check_in_scopes(code, expected, exec_func=self._replacing_exec) |
| |
| |
| __test__ = {'doctests' : doctests} |
| |
| def load_tests(loader, tests, pattern): |
| tests.addTest(doctest.DocTestSuite()) |
| return tests |
| |
| |
| if __name__ == "__main__": |
| unittest.main() |
