https://github.com/python/cpython/commit/a5274cd2158a0c7eaa6f54b4e74f8b4e92195e5e
commit: a5274cd2158a0c7eaa6f54b4e74f8b4e92195e5e
branch: 3.14
author: Mark Shannon <[email protected]>
committer: markshannon <[email protected]>
date: 2025-06-09T11:04:23+01:00
summary:
[3.14] GH-135171: Fix generator expressions one last time (hopefully)
(GH-135225)
* Add NULL check to FOR_ITER
* Move GET_ITER back to genexpr creation
files:
A
Misc/NEWS.d/next/Core_and_Builtins/2025-06-06-18-57-30.gh-issue-135171.0YtLq6.rst
M Lib/test/test_dis.py
M Lib/test/test_generators.py
M Lib/test/test_genexps.py
M Python/bytecodes.c
M Python/codegen.c
M Python/executor_cases.c.h
M Python/generated_cases.c.h
diff --git a/Lib/test/test_dis.py b/Lib/test/test_dis.py
index dbf90472ca34b6..48df7e530de2c1 100644
--- a/Lib/test/test_dis.py
+++ b/Lib/test/test_dis.py
@@ -204,6 +204,7 @@ def bug1333982(x=[]):
LOAD_CONST 1 (<code object <genexpr> at 0x...,
file "%s", line %d>)
MAKE_FUNCTION
LOAD_FAST_BORROW 0 (x)
+ GET_ITER
CALL 0
%3d LOAD_SMALL_INT 1
@@ -832,6 +833,7 @@ def foo(x):
MAKE_FUNCTION
SET_FUNCTION_ATTRIBUTE 8 (closure)
LOAD_DEREF 1 (y)
+ GET_ITER
CALL 0
CALL 1
RETURN_VALUE
@@ -851,8 +853,7 @@ def foo(x):
%4d RETURN_GENERATOR
POP_TOP
L1: RESUME 0
- LOAD_FAST_BORROW 0 (.0)
- GET_ITER
+ LOAD_FAST 0 (.0)
L2: FOR_ITER 14 (to L3)
STORE_FAST 1 (z)
LOAD_DEREF 2 (x)
diff --git a/Lib/test/test_generators.py b/Lib/test/test_generators.py
index 3e41c7b9663491..6c056b63f88480 100644
--- a/Lib/test/test_generators.py
+++ b/Lib/test/test_generators.py
@@ -318,21 +318,26 @@ def gen(it):
yield x
return gen(range(10))
- def process_tests(self, get_generator):
+ def process_tests(self, get_generator, is_expr):
+ err_iterator = "'.*' object is not an iterator"
+ err_iterable = "'.*' object is not iterable"
for obj in self.iterables:
g_obj = get_generator(obj)
with self.subTest(g_obj=g_obj, obj=obj):
- self.assertListEqual(list(g_obj), list(obj))
+ if is_expr:
+ self.assertRaisesRegex(TypeError, err_iterator, list,
g_obj)
+ else:
+ self.assertListEqual(list(g_obj), list(obj))
g_iter = get_generator(iter(obj))
with self.subTest(g_iter=g_iter, obj=obj):
self.assertListEqual(list(g_iter), list(obj))
- err_regex = "'.*' object is not iterable"
for obj in self.non_iterables:
g_obj = get_generator(obj)
with self.subTest(g_obj=g_obj):
- self.assertRaisesRegex(TypeError, err_regex, list, g_obj)
+ err = err_iterator if is_expr else err_iterable
+ self.assertRaisesRegex(TypeError, err, list, g_obj)
def test_modify_f_locals(self):
def modify_f_locals(g, local, obj):
@@ -345,8 +350,8 @@ def get_generator_genexpr(obj):
def get_generator_genfunc(obj):
return modify_f_locals(self.genfunc(), 'it', obj)
- self.process_tests(get_generator_genexpr)
- self.process_tests(get_generator_genfunc)
+ self.process_tests(get_generator_genexpr, True)
+ self.process_tests(get_generator_genfunc, False)
def test_new_gen_from_gi_code(self):
def new_gen_from_gi_code(g, obj):
@@ -359,8 +364,8 @@ def get_generator_genexpr(obj):
def get_generator_genfunc(obj):
return new_gen_from_gi_code(self.genfunc(), obj)
- self.process_tests(get_generator_genexpr)
- self.process_tests(get_generator_genfunc)
+ self.process_tests(get_generator_genexpr, True)
+ self.process_tests(get_generator_genfunc, False)
class ExceptionTest(unittest.TestCase):
diff --git a/Lib/test/test_genexps.py b/Lib/test/test_genexps.py
index fe5f18fa3f88a0..d90097dabea0c0 100644
--- a/Lib/test/test_genexps.py
+++ b/Lib/test/test_genexps.py
@@ -131,6 +131,14 @@
>>> list(g)
[1, 9, 25, 49, 81]
+Verify that the outermost for-expression makes an immediate check
+for iterability
+ >>> (i for i in 6)
+ Traceback (most recent call last):
+ File "<pyshell#4>", line 1, in -toplevel-
+ (i for i in 6)
+ TypeError: 'int' object is not iterable
+
Verify late binding for the innermost for-expression
>>> g = ((i,j) for i in range(3) for j in range(x))
diff --git
a/Misc/NEWS.d/next/Core_and_Builtins/2025-06-06-18-57-30.gh-issue-135171.0YtLq6.rst
b/Misc/NEWS.d/next/Core_and_Builtins/2025-06-06-18-57-30.gh-issue-135171.0YtLq6.rst
new file mode 100644
index 00000000000000..e46cb2b455f87e
--- /dev/null
+++
b/Misc/NEWS.d/next/Core_and_Builtins/2025-06-06-18-57-30.gh-issue-135171.0YtLq6.rst
@@ -0,0 +1,6 @@
+Reverts the behavior of generator expressions when created with a
+non-iterable to the pre-3.13 behavior of raising a TypeError. It is no
+longer possible to cause a crash in the debugger by altering the generator
+expression's local variables. This is achieved by moving the ``GET_ITER``
+instruction back to the creation of the generator expression and adding an
+additional check to ``FOR_ITER``.
diff --git a/Python/bytecodes.c b/Python/bytecodes.c
index 6a0766626402b0..568f61a9f5da1b 100644
--- a/Python/bytecodes.c
+++ b/Python/bytecodes.c
@@ -3155,7 +3155,14 @@ dummy_func(
replaced op(_FOR_ITER, (iter -- iter, next)) {
/* before: [iter]; after: [iter, iter()] *or* [] (and jump over
END_FOR.) */
PyObject *iter_o = PyStackRef_AsPyObjectBorrow(iter);
- PyObject *next_o = (*Py_TYPE(iter_o)->tp_iternext)(iter_o);
+ iternextfunc func = Py_TYPE(iter_o)->tp_iternext;
+ if (func == NULL) {
+ _PyErr_Format(tstate, PyExc_TypeError,
+ "'%.100s' object is not an iterator",
+ Py_TYPE(iter_o)->tp_name);
+ ERROR_NO_POP();
+ }
+ PyObject *next_o = func(iter_o);
if (next_o == NULL) {
if (_PyErr_Occurred(tstate)) {
int matches = _PyErr_ExceptionMatches(tstate,
PyExc_StopIteration);
@@ -3179,7 +3186,14 @@ dummy_func(
op(_FOR_ITER_TIER_TWO, (iter -- iter, next)) {
/* before: [iter]; after: [iter, iter()] *or* [] (and jump over
END_FOR.) */
PyObject *iter_o = PyStackRef_AsPyObjectBorrow(iter);
- PyObject *next_o = (*Py_TYPE(iter_o)->tp_iternext)(iter_o);
+ iternextfunc func = Py_TYPE(iter_o)->tp_iternext;
+ if (func == NULL) {
+ _PyErr_Format(tstate, PyExc_TypeError,
+ "'%.100s' object is not an iterator",
+ Py_TYPE(iter_o)->tp_name);
+ ERROR_NO_POP();
+ }
+ PyObject *next_o = func(iter_o);
if (next_o == NULL) {
if (_PyErr_Occurred(tstate)) {
int matches = _PyErr_ExceptionMatches(tstate,
PyExc_StopIteration);
@@ -3202,7 +3216,14 @@ dummy_func(
inst(INSTRUMENTED_FOR_ITER, (unused/1, iter -- iter, next)) {
PyObject *iter_o = PyStackRef_AsPyObjectBorrow(iter);
- PyObject *next_o = (*Py_TYPE(iter_o)->tp_iternext)(iter_o);
+ iternextfunc func = Py_TYPE(iter_o)->tp_iternext;
+ if (func == NULL) {
+ _PyErr_Format(tstate, PyExc_TypeError,
+ "'%.100s' object is not an iterator",
+ Py_TYPE(iter_o)->tp_name);
+ ERROR_NO_POP();
+ }
+ PyObject *next_o = func(iter_o);
if (next_o != NULL) {
next = PyStackRef_FromPyObjectSteal(next_o);
INSTRUMENTED_JUMP(this_instr, next_instr,
PY_MONITORING_EVENT_BRANCH_LEFT);
diff --git a/Python/codegen.c b/Python/codegen.c
index 1672b655fa9423..93c3a21266cb7d 100644
--- a/Python/codegen.c
+++ b/Python/codegen.c
@@ -4411,7 +4411,7 @@ codegen_sync_comprehension_generator(compiler *c,
location loc,
comprehension_ty gen = (comprehension_ty)asdl_seq_GET(generators,
gen_index);
-
+ int is_outer_genexpr = gen_index == 0 && type == COMP_GENEXP;
if (!iter_on_stack) {
if (gen_index == 0) {
assert(METADATA(c)->u_argcount == 1);
@@ -4442,14 +4442,15 @@ codegen_sync_comprehension_generator(compiler *c,
location loc,
}
if (IS_JUMP_TARGET_LABEL(start)) {
VISIT(c, expr, gen->iter);
- ADDOP(c, LOC(gen->iter), GET_ITER);
}
}
}
if (IS_JUMP_TARGET_LABEL(start)) {
depth++;
- ADDOP(c, LOC(gen->iter), GET_ITER);
+ if (!is_outer_genexpr) {
+ ADDOP(c, LOC(gen->iter), GET_ITER);
+ }
USE_LABEL(c, start);
ADDOP_JUMP(c, LOC(gen->iter), FOR_ITER, anchor);
}
@@ -4775,6 +4776,7 @@ codegen_comprehension(compiler *c, expr_ty e, int type,
location loc = LOC(e);
outermost = (comprehension_ty) asdl_seq_GET(generators, 0);
+ int is_sync_genexpr = type == COMP_GENEXP && !outermost->is_async;
if (is_inlined) {
VISIT(c, expr, outermost->iter);
if (push_inlined_comprehension_state(c, loc, entry, &inline_state)) {
@@ -4851,6 +4853,9 @@ codegen_comprehension(compiler *c, expr_ty e, int type,
Py_CLEAR(co);
VISIT(c, expr, outermost->iter);
+ if (is_sync_genexpr) {
+ ADDOP(c, loc, GET_ITER);
+ }
ADDOP_I(c, loc, CALL, 0);
if (is_async_comprehension && type != COMP_GENEXP) {
diff --git a/Python/executor_cases.c.h b/Python/executor_cases.c.h
index 3e51ac41fa3a2e..af4c39d03afa86 100644
--- a/Python/executor_cases.c.h
+++ b/Python/executor_cases.c.h
@@ -4273,8 +4273,17 @@
_PyStackRef next;
iter = stack_pointer[-1];
PyObject *iter_o = PyStackRef_AsPyObjectBorrow(iter);
+ iternextfunc func = Py_TYPE(iter_o)->tp_iternext;
+ if (func == NULL) {
+ _PyFrame_SetStackPointer(frame, stack_pointer);
+ _PyErr_Format(tstate, PyExc_TypeError,
+ "'%.100s' object is not an iterator",
+ Py_TYPE(iter_o)->tp_name);
+ stack_pointer = _PyFrame_GetStackPointer(frame);
+ JUMP_TO_ERROR();
+ }
_PyFrame_SetStackPointer(frame, stack_pointer);
- PyObject *next_o = (*Py_TYPE(iter_o)->tp_iternext)(iter_o);
+ PyObject *next_o = func(iter_o);
stack_pointer = _PyFrame_GetStackPointer(frame);
if (next_o == NULL) {
if (_PyErr_Occurred(tstate)) {
diff --git a/Python/generated_cases.c.h b/Python/generated_cases.c.h
index 7e8b05b747ed8f..9124035fc9e34d 100644
--- a/Python/generated_cases.c.h
+++ b/Python/generated_cases.c.h
@@ -5724,8 +5724,17 @@
// _FOR_ITER
{
PyObject *iter_o = PyStackRef_AsPyObjectBorrow(iter);
+ iternextfunc func = Py_TYPE(iter_o)->tp_iternext;
+ if (func == NULL) {
+ _PyFrame_SetStackPointer(frame, stack_pointer);
+ _PyErr_Format(tstate, PyExc_TypeError,
+ "'%.100s' object is not an iterator",
+ Py_TYPE(iter_o)->tp_name);
+ stack_pointer = _PyFrame_GetStackPointer(frame);
+ JUMP_TO_LABEL(error);
+ }
_PyFrame_SetStackPointer(frame, stack_pointer);
- PyObject *next_o = (*Py_TYPE(iter_o)->tp_iternext)(iter_o);
+ PyObject *next_o = func(iter_o);
stack_pointer = _PyFrame_GetStackPointer(frame);
if (next_o == NULL) {
if (_PyErr_Occurred(tstate)) {
@@ -7037,8 +7046,17 @@
/* Skip 1 cache entry */
iter = stack_pointer[-1];
PyObject *iter_o = PyStackRef_AsPyObjectBorrow(iter);
+ iternextfunc func = Py_TYPE(iter_o)->tp_iternext;
+ if (func == NULL) {
+ _PyFrame_SetStackPointer(frame, stack_pointer);
+ _PyErr_Format(tstate, PyExc_TypeError,
+ "'%.100s' object is not an iterator",
+ Py_TYPE(iter_o)->tp_name);
+ stack_pointer = _PyFrame_GetStackPointer(frame);
+ JUMP_TO_LABEL(error);
+ }
_PyFrame_SetStackPointer(frame, stack_pointer);
- PyObject *next_o = (*Py_TYPE(iter_o)->tp_iternext)(iter_o);
+ PyObject *next_o = func(iter_o);
stack_pointer = _PyFrame_GetStackPointer(frame);
if (next_o != NULL) {
next = PyStackRef_FromPyObjectSteal(next_o);
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