[Python-checkins] gh-104374: Remove access to class scopes for inlined comprehensions (#104528)
JelleZijlstra
webhook-mailer at python.org
Thu May 18 01:22:25 EDT 2023
https://github.com/python/cpython/commit/662aede68b0ea222cf3db4715b310e91c51b665f
commit: 662aede68b0ea222cf3db4715b310e91c51b665f
branch: main
author: Jelle Zijlstra <jelle.zijlstra at gmail.com>
committer: JelleZijlstra <jelle.zijlstra at gmail.com>
date: 2023-05-18T05:22:17Z
summary:
gh-104374: Remove access to class scopes for inlined comprehensions (#104528)
Co-authored-by: Carl Meyer <carl at oddbird.net>
files:
M Lib/test/test_listcomps.py
M Python/compile.c
M Python/symtable.c
diff --git a/Lib/test/test_listcomps.py b/Lib/test/test_listcomps.py
index 23e1b8c1ce31..985274dfd6cb 100644
--- a/Lib/test/test_listcomps.py
+++ b/Lib/test/test_listcomps.py
@@ -200,7 +200,8 @@ def f():
y = [g for x in [1]]
"""
outputs = {"y": [2]}
- self._check_in_scopes(code, outputs)
+ 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 = """
@@ -328,7 +329,8 @@ def test_nested_2(self):
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)
+ self._check_in_scopes(code, outputs, scopes=["module", "function"])
+ self._check_in_scopes(code, scopes=["class"], raises=NameError)
def test_nested_3(self):
code = """
@@ -379,6 +381,109 @@ def f():
with self.assertRaises(UnboundLocalError):
f()
+ 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)]})
+
__test__ = {'doctests' : doctests}
diff --git a/Python/compile.c b/Python/compile.c
index 60c845a821b6..07f8d6684770 100644
--- a/Python/compile.c
+++ b/Python/compile.c
@@ -388,6 +388,8 @@ struct compiler_unit {
instr_sequence u_instr_sequence; /* codegen output */
int u_nfblocks;
+ int u_in_inlined_comp;
+
struct fblockinfo u_fblock[CO_MAXBLOCKS];
_PyCompile_CodeUnitMetadata u_metadata;
@@ -1290,6 +1292,7 @@ compiler_enter_scope(struct compiler *c, identifier name,
}
u->u_nfblocks = 0;
+ u->u_in_inlined_comp = 0;
u->u_metadata.u_firstlineno = lineno;
u->u_metadata.u_consts = PyDict_New();
if (!u->u_metadata.u_consts) {
@@ -4137,7 +4140,7 @@ compiler_nameop(struct compiler *c, location loc,
case OP_DEREF:
switch (ctx) {
case Load:
- if (c->u->u_ste->ste_type == ClassBlock) {
+ if (c->u->u_ste->ste_type == ClassBlock && !c->u->u_in_inlined_comp) {
op = LOAD_FROM_DICT_OR_DEREF;
// First load the locals
if (codegen_addop_noarg(INSTR_SEQUENCE(c), LOAD_LOCALS, loc) < 0) {
@@ -4188,7 +4191,12 @@ compiler_nameop(struct compiler *c, location loc,
break;
case OP_NAME:
switch (ctx) {
- case Load: op = LOAD_NAME; break;
+ case Load:
+ op = (c->u->u_ste->ste_type == ClassBlock
+ && c->u->u_in_inlined_comp)
+ ? LOAD_GLOBAL
+ : LOAD_NAME;
+ break;
case Store: op = STORE_NAME; break;
case Del: op = DELETE_NAME; break;
}
@@ -5415,6 +5423,8 @@ push_inlined_comprehension_state(struct compiler *c, location loc,
PySTEntryObject *entry,
inlined_comprehension_state *state)
{
+ int in_class_block = (c->u->u_ste->ste_type == ClassBlock) && !c->u->u_in_inlined_comp;
+ c->u->u_in_inlined_comp++;
// iterate over names bound in the comprehension and ensure we isolate
// them from the outer scope as needed
PyObject *k, *v;
@@ -5426,7 +5436,7 @@ push_inlined_comprehension_state(struct compiler *c, location loc,
// at all; DEF_LOCAL | DEF_NONLOCAL can occur in the case of an
// assignment expression to a nonlocal in the comprehension, these don't
// need handling here since they shouldn't be isolated
- if (symbol & DEF_LOCAL && !(symbol & DEF_NONLOCAL)) {
+ if ((symbol & DEF_LOCAL && !(symbol & DEF_NONLOCAL)) || in_class_block) {
if (!_PyST_IsFunctionLike(c->u->u_ste)) {
// non-function scope: override this name to use fast locals
PyObject *orig = PyDict_GetItem(c->u->u_metadata.u_fasthidden, k);
@@ -5448,8 +5458,7 @@ push_inlined_comprehension_state(struct compiler *c, location loc,
long scope = (symbol >> SCOPE_OFFSET) & SCOPE_MASK;
PyObject *outv = PyDict_GetItemWithError(c->u->u_ste->ste_symbols, k);
if (outv == NULL) {
- assert(PyErr_Occurred());
- return ERROR;
+ outv = _PyLong_GetZero();
}
assert(PyLong_Check(outv));
long outsc = (PyLong_AS_LONG(outv) >> SCOPE_OFFSET) & SCOPE_MASK;
@@ -5523,6 +5532,7 @@ static int
pop_inlined_comprehension_state(struct compiler *c, location loc,
inlined_comprehension_state state)
{
+ c->u->u_in_inlined_comp--;
PyObject *k, *v;
Py_ssize_t pos = 0;
if (state.temp_symbols) {
diff --git a/Python/symtable.c b/Python/symtable.c
index f896f7cbe338..a319c239d99b 100644
--- a/Python/symtable.c
+++ b/Python/symtable.c
@@ -674,8 +674,9 @@ inline_comprehension(PySTEntryObject *ste, PySTEntryObject *comp,
}
// free vars in comprehension that are locals in outer scope can
- // now simply be locals, unless they are free in comp children
- if (!is_free_in_any_child(comp, k)) {
+ // now simply be locals, unless they are free in comp children,
+ // or if the outer scope is a class block
+ if (!is_free_in_any_child(comp, k) && ste->ste_type != ClassBlock) {
if (PySet_Discard(comp_free, k) < 0) {
return 0;
}
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