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gh-104619: never leak comprehension locals to outer locals() (#104637)

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Carl Meyer 2023-05-18 19:50:24 -06:00 committed by GitHub
parent 86e6f16ccb
commit 70c7796477
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GPG Key ID: 4AEE18F83AFDEB23
2 changed files with 32 additions and 21 deletions
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13
Lib/test/test_listcomps.py
View File

@ -516,6 +516,19 @@ class ListComprehensionTest(unittest.TestCase):
"""
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"])
__test__ = {'doctests' : doctests}

40
Python/compile.c
View File

@ -5490,31 +5490,29 @@ push_inlined_comprehension_state(struct compiler *c, location loc,
}
Py_DECREF(outv);
}
if (outsc == LOCAL || outsc == CELL || outsc == FREE) {
// local names bound in comprehension must be isolated from
// outer scope; push existing value (which may be NULL if
// not defined) on stack
// local names bound in comprehension must be isolated from
// outer scope; push existing value (which may be NULL if
// not defined) on stack
if (state->pushed_locals == NULL) {
state->pushed_locals = PyList_New(0);
if (state->pushed_locals == NULL) {
state->pushed_locals = PyList_New(0);
if (state->pushed_locals == NULL) {
return ERROR;
}
}
// in the case of a cell, this will actually push the cell
// itself to the stack, then we'll create a new one for the
// comprehension and restore the original one after
ADDOP_NAME(c, loc, LOAD_FAST_AND_CLEAR, k, varnames);
if (scope == CELL) {
if (outsc == FREE) {
ADDOP_NAME(c, loc, MAKE_CELL, k, freevars);
} else {
ADDOP_NAME(c, loc, MAKE_CELL, k, cellvars);
}
}
if (PyList_Append(state->pushed_locals, k) < 0) {
return ERROR;
}
}
// in the case of a cell, this will actually push the cell
// itself to the stack, then we'll create a new one for the
// comprehension and restore the original one after
ADDOP_NAME(c, loc, LOAD_FAST_AND_CLEAR, k, varnames);
if (scope == CELL) {
if (outsc == FREE) {
ADDOP_NAME(c, loc, MAKE_CELL, k, freevars);
} else {
ADDOP_NAME(c, loc, MAKE_CELL, k, cellvars);
}
}
if (PyList_Append(state->pushed_locals, k) < 0) {
return ERROR;
}
}
}
if (state->pushed_locals) {