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gh-104482: Fix error handling bugs in ast.c (#104483)
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@iritkatriel
iritkatriel authored May 15, 2023
1 parent 26baa74 commit 8a3702f
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Showing 4 changed files with 45 additions and 19 deletions.
6 changes: 6 additions & 0 deletions Lib/test/test_ast.py
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Original file line number Diff line number Diff line change
Expand Up @@ -2035,6 +2035,12 @@ def test_stdlib_validates(self):
kwd_attrs=[],
kwd_patterns=[ast.MatchStar()]
),
ast.MatchClass(
constant_true, # invalid name
patterns=[],
kwd_attrs=['True'],
kwd_patterns=[pattern_1]
),
ast.MatchSequence(
[
ast.MatchStar("True")
Expand Down
1 change: 1 addition & 0 deletions Misc/NEWS.d/next/Core and Builtins/2023-05-14-18-56-54.gh-issue-104482.yaQsv8.rst
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Original file line number Diff line number Diff line change
@@ -0,0 +1 @@
Fix three error handling bugs in ast.c's validation of pattern matching statements.
56 changes: 37 additions & 19 deletions Python/ast.c
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Original file line number Diff line number Diff line change
Expand Up @@ -46,6 +46,7 @@ static int validate_pattern(struct validator *, pattern_ty, int);
static int
validate_name(PyObject *name)
{
assert(!PyErr_Occurred());
assert(PyUnicode_Check(name));
static const char * const forbidden[] = {
"None",
Expand All @@ -65,12 +66,12 @@ validate_name(PyObject *name)
static int
validate_comprehension(struct validator *state, asdl_comprehension_seq *gens)
{
Py_ssize_t i;
assert(!PyErr_Occurred());
if (!asdl_seq_LEN(gens)) {
PyErr_SetString(PyExc_ValueError, "comprehension with no generators");
return 0;
}
for (i = 0; i < asdl_seq_LEN(gens); i++) {
for (Py_ssize_t i = 0; i < asdl_seq_LEN(gens); i++) {
comprehension_ty comp = asdl_seq_GET(gens, i);
if (!validate_expr(state, comp->target, Store) ||
!validate_expr(state, comp->iter, Load) ||
Expand All @@ -83,8 +84,8 @@ validate_comprehension(struct validator *state, asdl_comprehension_seq *gens)
static int
validate_keywords(struct validator *state, asdl_keyword_seq *keywords)
{
Py_ssize_t i;
for (i = 0; i < asdl_seq_LEN(keywords); i++)
assert(!PyErr_Occurred());
for (Py_ssize_t i = 0; i < asdl_seq_LEN(keywords); i++)
if (!validate_expr(state, (asdl_seq_GET(keywords, i))->value, Load))
return 0;
return 1;
Expand All @@ -93,8 +94,8 @@ validate_keywords(struct validator *state, asdl_keyword_seq *keywords)
static int
validate_args(struct validator *state, asdl_arg_seq *args)
{
Py_ssize_t i;
for (i = 0; i < asdl_seq_LEN(args); i++) {
assert(!PyErr_Occurred());
for (Py_ssize_t i = 0; i < asdl_seq_LEN(args); i++) {
arg_ty arg = asdl_seq_GET(args, i);
VALIDATE_POSITIONS(arg);
if (arg->annotation && !validate_expr(state, arg->annotation, Load))
Expand All @@ -121,6 +122,7 @@ expr_context_name(expr_context_ty ctx)
static int
validate_arguments(struct validator *state, arguments_ty args)
{
assert(!PyErr_Occurred());
if (!validate_args(state, args->posonlyargs) || !validate_args(state, args->args)) {
return 0;
}
Expand Down Expand Up @@ -149,6 +151,7 @@ validate_arguments(struct validator *state, arguments_ty args)
static int
validate_constant(struct validator *state, PyObject *value)
{
assert(!PyErr_Occurred());
if (value == Py_None || value == Py_Ellipsis)
return 1;

Expand Down Expand Up @@ -205,6 +208,7 @@ validate_constant(struct validator *state, PyObject *value)
static int
validate_expr(struct validator *state, expr_ty exp, expr_context_ty ctx)
{
assert(!PyErr_Occurred());
VALIDATE_POSITIONS(exp);
int ret = -1;
if (++state->recursion_depth > state->recursion_limit) {
Expand Down Expand Up @@ -465,6 +469,7 @@ ensure_literal_complex(expr_ty exp)
static int
validate_pattern_match_value(struct validator *state, expr_ty exp)
{
assert(!PyErr_Occurred());
if (!validate_expr(state, exp, Load)) {
return 0;
}
Expand Down Expand Up @@ -518,6 +523,7 @@ validate_pattern_match_value(struct validator *state, expr_ty exp)
static int
validate_capture(PyObject *name)
{
assert(!PyErr_Occurred());
if (_PyUnicode_EqualToASCIIString(name, "_")) {
PyErr_Format(PyExc_ValueError, "can't capture name '_' in patterns");
return 0;
Expand All @@ -528,6 +534,7 @@ validate_capture(PyObject *name)
static int
validate_pattern(struct validator *state, pattern_ty p, int star_ok)
{
assert(!PyErr_Occurred());
VALIDATE_POSITIONS(p);
int ret = -1;
if (++state->recursion_depth > state->recursion_limit) {
Expand Down Expand Up @@ -580,7 +587,9 @@ validate_pattern(struct validator *state, pattern_ty p, int star_ok)
break;
}
}

if (ret == 0) {
break;
}
ret = validate_patterns(state, p->v.MatchMapping.patterns, /*star_ok=*/0);
break;
case MatchClass_kind:
Expand Down Expand Up @@ -611,6 +620,9 @@ validate_pattern(struct validator *state, pattern_ty p, int star_ok)
break;
}
}
if (ret == 0) {
break;
}

for (Py_ssize_t i = 0; i < asdl_seq_LEN(p->v.MatchClass.kwd_attrs); i++) {
PyObject *identifier = asdl_seq_GET(p->v.MatchClass.kwd_attrs, i);
Expand All @@ -619,6 +631,9 @@ validate_pattern(struct validator *state, pattern_ty p, int star_ok)
break;
}
}
if (ret == 0) {
break;
}

if (!validate_patterns(state, p->v.MatchClass.patterns, /*star_ok=*/0)) {
ret = 0;
Expand Down Expand Up @@ -685,22 +700,24 @@ _validate_nonempty_seq(asdl_seq *seq, const char *what, const char *owner)
static int
validate_assignlist(struct validator *state, asdl_expr_seq *targets, expr_context_ty ctx)
{
assert(!PyErr_Occurred());
return validate_nonempty_seq(targets, "targets", ctx == Del ? "Delete" : "Assign") &&
validate_exprs(state, targets, ctx, 0);
}

static int
validate_body(struct validator *state, asdl_stmt_seq *body, const char *owner)
{
assert(!PyErr_Occurred());
return validate_nonempty_seq(body, "body", owner) && validate_stmts(state, body);
}

static int
validate_stmt(struct validator *state, stmt_ty stmt)
{
assert(!PyErr_Occurred());
VALIDATE_POSITIONS(stmt);
int ret = -1;
Py_ssize_t i;
if (++state->recursion_depth > state->recursion_limit) {
PyErr_SetString(PyExc_RecursionError,
"maximum recursion depth exceeded during compilation");
Expand Down Expand Up @@ -771,7 +788,7 @@ validate_stmt(struct validator *state, stmt_ty stmt)
case With_kind:
if (!validate_nonempty_seq(stmt->v.With.items, "items", "With"))
return 0;
for (i = 0; i < asdl_seq_LEN(stmt->v.With.items); i++) {
for (Py_ssize_t i = 0; i < asdl_seq_LEN(stmt->v.With.items); i++) {
withitem_ty item = asdl_seq_GET(stmt->v.With.items, i);
if (!validate_expr(state, item->context_expr, Load) ||
(item->optional_vars && !validate_expr(state, item->optional_vars, Store)))
Expand All @@ -782,7 +799,7 @@ validate_stmt(struct validator *state, stmt_ty stmt)
case AsyncWith_kind:
if (!validate_nonempty_seq(stmt->v.AsyncWith.items, "items", "AsyncWith"))
return 0;
for (i = 0; i < asdl_seq_LEN(stmt->v.AsyncWith.items); i++) {
for (Py_ssize_t i = 0; i < asdl_seq_LEN(stmt->v.AsyncWith.items); i++) {
withitem_ty item = asdl_seq_GET(stmt->v.AsyncWith.items, i);
if (!validate_expr(state, item->context_expr, Load) ||
(item->optional_vars && !validate_expr(state, item->optional_vars, Store)))
Expand All @@ -795,7 +812,7 @@ validate_stmt(struct validator *state, stmt_ty stmt)
|| !validate_nonempty_seq(stmt->v.Match.cases, "cases", "Match")) {
return 0;
}
for (i = 0; i < asdl_seq_LEN(stmt->v.Match.cases); i++) {
for (Py_ssize_t i = 0; i < asdl_seq_LEN(stmt->v.Match.cases); i++) {
match_case_ty m = asdl_seq_GET(stmt->v.Match.cases, i);
if (!validate_pattern(state, m->pattern, /*star_ok=*/0)
|| (m->guard && !validate_expr(state, m->guard, Load))
Expand Down Expand Up @@ -830,7 +847,7 @@ validate_stmt(struct validator *state, stmt_ty stmt)
PyErr_SetString(PyExc_ValueError, "Try has orelse but no except handlers");
return 0;
}
for (i = 0; i < asdl_seq_LEN(stmt->v.Try.handlers); i++) {
for (Py_ssize_t i = 0; i < asdl_seq_LEN(stmt->v.Try.handlers); i++) {
excepthandler_ty handler = asdl_seq_GET(stmt->v.Try.handlers, i);
VALIDATE_POSITIONS(handler);
if ((handler->v.ExceptHandler.type &&
Expand All @@ -856,7 +873,7 @@ validate_stmt(struct validator *state, stmt_ty stmt)
PyErr_SetString(PyExc_ValueError, "TryStar has orelse but no except handlers");
return 0;
}
for (i = 0; i < asdl_seq_LEN(stmt->v.TryStar.handlers); i++) {
for (Py_ssize_t i = 0; i < asdl_seq_LEN(stmt->v.TryStar.handlers); i++) {
excepthandler_ty handler = asdl_seq_GET(stmt->v.TryStar.handlers, i);
if ((handler->v.ExceptHandler.type &&
!validate_expr(state, handler->v.ExceptHandler.type, Load)) ||
Expand Down Expand Up @@ -916,8 +933,8 @@ validate_stmt(struct validator *state, stmt_ty stmt)
static int
validate_stmts(struct validator *state, asdl_stmt_seq *seq)
{
Py_ssize_t i;
for (i = 0; i < asdl_seq_LEN(seq); i++) {
assert(!PyErr_Occurred());
for (Py_ssize_t i = 0; i < asdl_seq_LEN(seq); i++) {
stmt_ty stmt = asdl_seq_GET(seq, i);
if (stmt) {
if (!validate_stmt(state, stmt))
Expand All @@ -935,8 +952,8 @@ validate_stmts(struct validator *state, asdl_stmt_seq *seq)
static int
validate_exprs(struct validator *state, asdl_expr_seq *exprs, expr_context_ty ctx, int null_ok)
{
Py_ssize_t i;
for (i = 0; i < asdl_seq_LEN(exprs); i++) {
assert(!PyErr_Occurred());
for (Py_ssize_t i = 0; i < asdl_seq_LEN(exprs); i++) {
expr_ty expr = asdl_seq_GET(exprs, i);
if (expr) {
if (!validate_expr(state, expr, ctx))
Expand All @@ -955,8 +972,8 @@ validate_exprs(struct validator *state, asdl_expr_seq *exprs, expr_context_ty ct
static int
validate_patterns(struct validator *state, asdl_pattern_seq *patterns, int star_ok)
{
Py_ssize_t i;
for (i = 0; i < asdl_seq_LEN(patterns); i++) {
assert(!PyErr_Occurred());
for (Py_ssize_t i = 0; i < asdl_seq_LEN(patterns); i++) {
pattern_ty pattern = asdl_seq_GET(patterns, i);
if (!validate_pattern(state, pattern, star_ok)) {
return 0;
Expand All @@ -972,6 +989,7 @@ validate_patterns(struct validator *state, asdl_pattern_seq *patterns, int star_
int
_PyAST_Validate(mod_ty mod)
{
assert(!PyErr_Occurred());
int res = -1;
struct validator state;
PyThreadState *tstate;
Expand Down
1 change: 1 addition & 0 deletions Python/compile.c
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Original file line number Diff line number Diff line change
Expand Up @@ -567,6 +567,7 @@ PyCodeObject *
_PyAST_Compile(mod_ty mod, PyObject *filename, PyCompilerFlags *pflags,
int optimize, PyArena *arena)
{
assert(!PyErr_Occurred());
struct compiler *c = new_compiler(mod, filename, pflags, optimize, arena);
if (c == NULL) {
return NULL;
Expand Down

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