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cpython/Python/ast.c

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/*
* This file exposes PyAST_Validate interface to check the integrity
* of the given abstract syntax tree (potentially constructed manually).
*/
#include "Python.h"
#include "pycore_ast.h" // asdl_stmt_seq
#include "pycore_pystate.h" // _PyThreadState_GET()
#include <assert.h>
#include <stdbool.h>
struct validator {
int recursion_depth; /* current recursion depth */
int recursion_limit; /* recursion limit */
};
static int validate_stmts(struct validator *, asdl_stmt_seq *);
static int validate_exprs(struct validator *, asdl_expr_seq *, expr_context_ty, int);
static int validate_patterns(struct validator *, asdl_pattern_seq *, int);
static int validate_type_params(struct validator *, asdl_type_param_seq *);
static int _validate_nonempty_seq(asdl_seq *, const char *, const char *);
static int validate_stmt(struct validator *, stmt_ty);
static int validate_expr(struct validator *, expr_ty, expr_context_ty);
static int validate_pattern(struct validator *, pattern_ty, int);
static int validate_typeparam(struct validator *, type_param_ty);
#define VALIDATE_POSITIONS(node) \
if (node->lineno > node->end_lineno) { \
PyErr_Format(PyExc_ValueError, \
"AST node line range (%d, %d) is not valid", \
node->lineno, node->end_lineno); \
return 0; \
} \
if ((node->lineno < 0 && node->end_lineno != node->lineno) || \
(node->col_offset < 0 && node->col_offset != node->end_col_offset)) { \
PyErr_Format(PyExc_ValueError, \
"AST node column range (%d, %d) for line range (%d, %d) is not valid", \
node->col_offset, node->end_col_offset, node->lineno, node->end_lineno); \
return 0; \
} \
if (node->lineno == node->end_lineno && node->col_offset > node->end_col_offset) { \
PyErr_Format(PyExc_ValueError, \
"line %d, column %d-%d is not a valid range", \
node->lineno, node->col_offset, node->end_col_offset); \
return 0; \
}
static int
validate_name(PyObject *name)
{
assert(!PyErr_Occurred());
assert(PyUnicode_Check(name));
static const char * const forbidden[] = {
"None",
"True",
"False",
NULL
};
for (int i = 0; forbidden[i] != NULL; i++) {
if (_PyUnicode_EqualToASCIIString(name, forbidden[i])) {
PyErr_Format(PyExc_ValueError, "identifier field can't represent '%s' constant", forbidden[i]);
return 0;
}
}
return 1;
}
static int
validate_comprehension(struct validator *state, asdl_comprehension_seq *gens)
{
assert(!PyErr_Occurred());
if (!asdl_seq_LEN(gens)) {
PyErr_SetString(PyExc_ValueError, "comprehension with no generators");
return 0;
}
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) ||
!validate_exprs(state, comp->ifs, Load, 0))
return 0;
}
return 1;
}
static int
validate_keywords(struct validator *state, asdl_keyword_seq *keywords)
{
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;
}
static int
validate_args(struct validator *state, asdl_arg_seq *args)
{
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))
return 0;
}
return 1;
}
static const char *
expr_context_name(expr_context_ty ctx)
{
switch (ctx) {
case Load:
return "Load";
case Store:
return "Store";
case Del:
return "Del";
// No default case so compiler emits warning for unhandled cases
}
Py_UNREACHABLE();
}
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;
}
if (args->vararg && args->vararg->annotation
&& !validate_expr(state, args->vararg->annotation, Load)) {
return 0;
}
if (!validate_args(state, args->kwonlyargs))
return 0;
if (args->kwarg && args->kwarg->annotation
&& !validate_expr(state, args->kwarg->annotation, Load)) {
return 0;
}
if (asdl_seq_LEN(args->defaults) > asdl_seq_LEN(args->posonlyargs) + asdl_seq_LEN(args->args)) {
PyErr_SetString(PyExc_ValueError, "more positional defaults than args on arguments");
return 0;
}
if (asdl_seq_LEN(args->kw_defaults) != asdl_seq_LEN(args->kwonlyargs)) {
PyErr_SetString(PyExc_ValueError, "length of kwonlyargs is not the same as "
"kw_defaults on arguments");
return 0;
}
return validate_exprs(state, args->defaults, Load, 0) && validate_exprs(state, args->kw_defaults, Load, 1);
}
static int
validate_constant(struct validator *state, PyObject *value)
{
assert(!PyErr_Occurred());
if (value == Py_None || value == Py_Ellipsis)
return 1;
if (PyLong_CheckExact(value)
|| PyFloat_CheckExact(value)
|| PyComplex_CheckExact(value)
|| PyBool_Check(value)
|| PyUnicode_CheckExact(value)
|| PyBytes_CheckExact(value))
return 1;
if (PyTuple_CheckExact(value) || PyFrozenSet_CheckExact(value)) {
if (++state->recursion_depth > state->recursion_limit) {
PyErr_SetString(PyExc_RecursionError,
"maximum recursion depth exceeded during compilation");
return 0;
}
PyObject *it = PyObject_GetIter(value);
if (it == NULL)
return 0;
while (1) {
PyObject *item = PyIter_Next(it);
if (item == NULL) {
if (PyErr_Occurred()) {
Py_DECREF(it);
return 0;
}
break;
}
if (!validate_constant(state, item)) {
Py_DECREF(it);
Py_DECREF(item);
return 0;
}
Py_DECREF(item);
}
Py_DECREF(it);
--state->recursion_depth;
return 1;
}
if (!PyErr_Occurred()) {
PyErr_Format(PyExc_TypeError,
"got an invalid type in Constant: %s",
_PyType_Name(Py_TYPE(value)));
}
return 0;
}
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) {
PyErr_SetString(PyExc_RecursionError,
"maximum recursion depth exceeded during compilation");
return 0;
}
int check_ctx = 1;
expr_context_ty actual_ctx;
/* First check expression context. */
switch (exp->kind) {
case Attribute_kind:
actual_ctx = exp->v.Attribute.ctx;
break;
case Subscript_kind:
actual_ctx = exp->v.Subscript.ctx;
break;
case Starred_kind:
actual_ctx = exp->v.Starred.ctx;
break;
case Name_kind:
if (!validate_name(exp->v.Name.id)) {
return 0;
}
actual_ctx = exp->v.Name.ctx;
break;
case List_kind:
actual_ctx = exp->v.List.ctx;
break;
case Tuple_kind:
actual_ctx = exp->v.Tuple.ctx;
break;
default:
if (ctx != Load) {
PyErr_Format(PyExc_ValueError, "expression which can't be "
"assigned to in %s context", expr_context_name(ctx));
return 0;
}
check_ctx = 0;
/* set actual_ctx to prevent gcc warning */
actual_ctx = 0;
}
if (check_ctx && actual_ctx != ctx) {
PyErr_Format(PyExc_ValueError, "expression must have %s context but has %s instead",
expr_context_name(ctx), expr_context_name(actual_ctx));
return 0;
}
/* Now validate expression. */
switch (exp->kind) {
case BoolOp_kind:
if (asdl_seq_LEN(exp->v.BoolOp.values) < 2) {
PyErr_SetString(PyExc_ValueError, "BoolOp with less than 2 values");
return 0;
}
ret = validate_exprs(state, exp->v.BoolOp.values, Load, 0);
break;
case BinOp_kind:
ret = validate_expr(state, exp->v.BinOp.left, Load) &&
validate_expr(state, exp->v.BinOp.right, Load);
break;
case UnaryOp_kind:
ret = validate_expr(state, exp->v.UnaryOp.operand, Load);
break;
case Lambda_kind:
ret = validate_arguments(state, exp->v.Lambda.args) &&
validate_expr(state, exp->v.Lambda.body, Load);
break;
case IfExp_kind:
ret = validate_expr(state, exp->v.IfExp.test, Load) &&
validate_expr(state, exp->v.IfExp.body, Load) &&
validate_expr(state, exp->v.IfExp.orelse, Load);
break;
case Dict_kind:
if (asdl_seq_LEN(exp->v.Dict.keys) != asdl_seq_LEN(exp->v.Dict.values)) {
PyErr_SetString(PyExc_ValueError,
"Dict doesn't have the same number of keys as values");
return 0;
}
/* null_ok=1 for keys expressions to allow dict unpacking to work in
dict literals, i.e. ``{**{a:b}}`` */
ret = validate_exprs(state, exp->v.Dict.keys, Load, /*null_ok=*/ 1) &&
validate_exprs(state, exp->v.Dict.values, Load, /*null_ok=*/ 0);
break;
case Set_kind:
ret = validate_exprs(state, exp->v.Set.elts, Load, 0);
break;
#define COMP(NAME) \
case NAME ## _kind: \
ret = validate_comprehension(state, exp->v.NAME.generators) && \
validate_expr(state, exp->v.NAME.elt, Load); \
break;
COMP(ListComp)
COMP(SetComp)
COMP(GeneratorExp)
#undef COMP
case DictComp_kind:
ret = validate_comprehension(state, exp->v.DictComp.generators) &&
validate_expr(state, exp->v.DictComp.key, Load) &&
validate_expr(state, exp->v.DictComp.value, Load);
break;
case Yield_kind:
ret = !exp->v.Yield.value || validate_expr(state, exp->v.Yield.value, Load);
break;
case YieldFrom_kind:
ret = validate_expr(state, exp->v.YieldFrom.value, Load);
break;
case Await_kind:
ret = validate_expr(state, exp->v.Await.value, Load);
break;
case Compare_kind:
if (!asdl_seq_LEN(exp->v.Compare.comparators)) {
PyErr_SetString(PyExc_ValueError, "Compare with no comparators");
return 0;
}
if (asdl_seq_LEN(exp->v.Compare.comparators) !=
asdl_seq_LEN(exp->v.Compare.ops)) {
PyErr_SetString(PyExc_ValueError, "Compare has a different number "
"of comparators and operands");
return 0;
}
ret = validate_exprs(state, exp->v.Compare.comparators, Load, 0) &&
validate_expr(state, exp->v.Compare.left, Load);
break;
case Call_kind:
ret = validate_expr(state, exp->v.Call.func, Load) &&
validate_exprs(state, exp->v.Call.args, Load, 0) &&
validate_keywords(state, exp->v.Call.keywords);
break;
case Constant_kind:
if (!validate_constant(state, exp->v.Constant.value)) {
return 0;
}
ret = 1;
break;
case JoinedStr_kind:
ret = validate_exprs(state, exp->v.JoinedStr.values, Load, 0);
break;
case FormattedValue_kind:
if (validate_expr(state, exp->v.FormattedValue.value, Load) == 0)
return 0;
if (exp->v.FormattedValue.format_spec) {
ret = validate_expr(state, exp->v.FormattedValue.format_spec, Load);
break;
}
ret = 1;
break;
case Attribute_kind:
ret = validate_expr(state, exp->v.Attribute.value, Load);
break;
case Subscript_kind:
ret = validate_expr(state, exp->v.Subscript.slice, Load) &&
validate_expr(state, exp->v.Subscript.value, Load);
break;
case Starred_kind:
ret = validate_expr(state, exp->v.Starred.value, ctx);
break;
case Slice_kind:
ret = (!exp->v.Slice.lower || validate_expr(state, exp->v.Slice.lower, Load)) &&
(!exp->v.Slice.upper || validate_expr(state, exp->v.Slice.upper, Load)) &&
(!exp->v.Slice.step || validate_expr(state, exp->v.Slice.step, Load));
break;
case List_kind:
ret = validate_exprs(state, exp->v.List.elts, ctx, 0);
break;
case Tuple_kind:
ret = validate_exprs(state, exp->v.Tuple.elts, ctx, 0);
break;
case NamedExpr_kind:
ret = validate_expr(state, exp->v.NamedExpr.value, Load);
break;
/* This last case doesn't have any checking. */
case Name_kind:
ret = 1;
break;
// No default case so compiler emits warning for unhandled cases
}
if (ret < 0) {
PyErr_SetString(PyExc_SystemError, "unexpected expression");
ret = 0;
}
state->recursion_depth--;
return ret;
}
// Note: the ensure_literal_* functions are only used to validate a restricted
// set of non-recursive literals that have already been checked with
// validate_expr, so they don't accept the validator state
static int
ensure_literal_number(expr_ty exp, bool allow_real, bool allow_imaginary)
{
assert(exp->kind == Constant_kind);
PyObject *value = exp->v.Constant.value;
return (allow_real && PyFloat_CheckExact(value)) ||
(allow_real && PyLong_CheckExact(value)) ||
(allow_imaginary && PyComplex_CheckExact(value));
}
static int
ensure_literal_negative(expr_ty exp, bool allow_real, bool allow_imaginary)
{
assert(exp->kind == UnaryOp_kind);
// Must be negation ...
if (exp->v.UnaryOp.op != USub) {
return 0;
}
// ... of a constant ...
expr_ty operand = exp->v.UnaryOp.operand;
if (operand->kind != Constant_kind) {
return 0;
}
// ... number
return ensure_literal_number(operand, allow_real, allow_imaginary);
}
static int
ensure_literal_complex(expr_ty exp)
{
assert(exp->kind == BinOp_kind);
expr_ty left = exp->v.BinOp.left;
expr_ty right = exp->v.BinOp.right;
// Ensure op is addition or subtraction
if (exp->v.BinOp.op != Add && exp->v.BinOp.op != Sub) {
return 0;
}
// Check LHS is a real number (potentially signed)
switch (left->kind)
{
case Constant_kind:
if (!ensure_literal_number(left, /*real=*/true, /*imaginary=*/false)) {
return 0;
}
break;
case UnaryOp_kind:
if (!ensure_literal_negative(left, /*real=*/true, /*imaginary=*/false)) {
return 0;
}
break;
default:
return 0;
}
// Check RHS is an imaginary number (no separate sign allowed)
switch (right->kind)
{
case Constant_kind:
if (!ensure_literal_number(right, /*real=*/false, /*imaginary=*/true)) {
return 0;
}
break;
default:
return 0;
}
return 1;
}
static int
validate_pattern_match_value(struct validator *state, expr_ty exp)
{
assert(!PyErr_Occurred());
if (!validate_expr(state, exp, Load)) {
return 0;
}
switch (exp->kind)
{
case Constant_kind:
/* Ellipsis and immutable sequences are not allowed.
For True, False and None, MatchSingleton() should
be used */
if (!validate_expr(state, exp, Load)) {
return 0;
}
PyObject *literal = exp->v.Constant.value;
if (PyLong_CheckExact(literal) || PyFloat_CheckExact(literal) ||
PyBytes_CheckExact(literal) || PyComplex_CheckExact(literal) ||
PyUnicode_CheckExact(literal)) {
return 1;
}
PyErr_SetString(PyExc_ValueError,
"unexpected constant inside of a literal pattern");
return 0;
case Attribute_kind:
// Constants and attribute lookups are always permitted
return 1;
case UnaryOp_kind:
// Negated numbers are permitted (whether real or imaginary)
// Compiler will complain if AST folding doesn't create a constant
if (ensure_literal_negative(exp, /*real=*/true, /*imaginary=*/true)) {
return 1;
}
break;
case BinOp_kind:
// Complex literals are permitted
// Compiler will complain if AST folding doesn't create a constant
if (ensure_literal_complex(exp)) {
return 1;
}
break;
case JoinedStr_kind:
// Handled in the later stages
return 1;
default:
break;
}
PyErr_SetString(PyExc_ValueError,
"patterns may only match literals and attribute lookups");
return 0;
}
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;
}
return validate_name(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) {
PyErr_SetString(PyExc_RecursionError,
"maximum recursion depth exceeded during compilation");
return 0;
}
switch (p->kind) {
case MatchValue_kind:
ret = validate_pattern_match_value(state, p->v.MatchValue.value);
break;
case MatchSingleton_kind:
ret = p->v.MatchSingleton.value == Py_None || PyBool_Check(p->v.MatchSingleton.value);
if (!ret) {
PyErr_SetString(PyExc_ValueError,
"MatchSingleton can only contain True, False and None");
}
break;
case MatchSequence_kind:
ret = validate_patterns(state, p->v.MatchSequence.patterns, /*star_ok=*/1);
break;
case MatchMapping_kind:
if (asdl_seq_LEN(p->v.MatchMapping.keys) != asdl_seq_LEN(p->v.MatchMapping.patterns)) {
PyErr_SetString(PyExc_ValueError,
"MatchMapping doesn't have the same number of keys as patterns");
ret = 0;
break;
}
if (p->v.MatchMapping.rest && !validate_capture(p->v.MatchMapping.rest)) {
ret = 0;
break;
}
asdl_expr_seq *keys = p->v.MatchMapping.keys;
for (Py_ssize_t i = 0; i < asdl_seq_LEN(keys); i++) {
expr_ty key = asdl_seq_GET(keys, i);
if (key->kind == Constant_kind) {
PyObject *literal = key->v.Constant.value;
if (literal == Py_None || PyBool_Check(literal)) {
/* validate_pattern_match_value will ensure the key
doesn't contain True, False and None but it is
syntactically valid, so we will pass those on in
a special case. */
continue;
}
}
if (!validate_pattern_match_value(state, key)) {
ret = 0;
break;
}
}
if (ret == 0) {
break;
}
ret = validate_patterns(state, p->v.MatchMapping.patterns, /*star_ok=*/0);
break;
case MatchClass_kind:
if (asdl_seq_LEN(p->v.MatchClass.kwd_attrs) != asdl_seq_LEN(p->v.MatchClass.kwd_patterns)) {
PyErr_SetString(PyExc_ValueError,
"MatchClass doesn't have the same number of keyword attributes as patterns");
ret = 0;
break;
}
if (!validate_expr(state, p->v.MatchClass.cls, Load)) {
ret = 0;
break;
}
expr_ty cls = p->v.MatchClass.cls;
while (1) {
if (cls->kind == Name_kind) {
break;
}
else if (cls->kind == Attribute_kind) {
cls = cls->v.Attribute.value;
continue;
}
else {
PyErr_SetString(PyExc_ValueError,
"MatchClass cls field can only contain Name or Attribute nodes.");
ret = 0;
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);
if (!validate_name(identifier)) {
ret = 0;
break;
}
}
if (ret == 0) {
break;
}
if (!validate_patterns(state, p->v.MatchClass.patterns, /*star_ok=*/0)) {
ret = 0;
break;
}
ret = validate_patterns(state, p->v.MatchClass.kwd_patterns, /*star_ok=*/0);
break;
case MatchStar_kind:
if (!star_ok) {
PyErr_SetString(PyExc_ValueError, "can't use MatchStar here");
ret = 0;
break;
}
ret = p->v.MatchStar.name == NULL || validate_capture(p->v.MatchStar.name);
break;
case MatchAs_kind:
if (p->v.MatchAs.name && !validate_capture(p->v.MatchAs.name)) {
ret = 0;
break;
}
if (p->v.MatchAs.pattern == NULL) {
ret = 1;
}
else if (p->v.MatchAs.name == NULL) {
PyErr_SetString(PyExc_ValueError,
"MatchAs must specify a target name if a pattern is given");
ret = 0;
}
else {
ret = validate_pattern(state, p->v.MatchAs.pattern, /*star_ok=*/0);
}
break;
case MatchOr_kind:
if (asdl_seq_LEN(p->v.MatchOr.patterns) < 2) {
PyErr_SetString(PyExc_ValueError,
"MatchOr requires at least 2 patterns");
ret = 0;
break;
}
ret = validate_patterns(state, p->v.MatchOr.patterns, /*star_ok=*/0);
break;
// No default case, so the compiler will emit a warning if new pattern
// kinds are added without being handled here
}
if (ret < 0) {
PyErr_SetString(PyExc_SystemError, "unexpected pattern");
ret = 0;
}
state->recursion_depth--;
return ret;
}
static int
_validate_nonempty_seq(asdl_seq *seq, const char *what, const char *owner)
{
if (asdl_seq_LEN(seq))
return 1;
PyErr_Format(PyExc_ValueError, "empty %s on %s", what, owner);
return 0;
}
#define validate_nonempty_seq(seq, what, owner) _validate_nonempty_seq((asdl_seq*)seq, what, 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;
if (++state->recursion_depth > state->recursion_limit) {
PyErr_SetString(PyExc_RecursionError,
"maximum recursion depth exceeded during compilation");
return 0;
}
switch (stmt->kind) {
case FunctionDef_kind:
ret = validate_body(state, stmt->v.FunctionDef.body, "FunctionDef") &&
validate_type_params(state, stmt->v.FunctionDef.type_params) &&
validate_arguments(state, stmt->v.FunctionDef.args) &&
validate_exprs(state, stmt->v.FunctionDef.decorator_list, Load, 0) &&
(!stmt->v.FunctionDef.returns ||
validate_expr(state, stmt->v.FunctionDef.returns, Load));
break;
case ClassDef_kind:
ret = validate_body(state, stmt->v.ClassDef.body, "ClassDef") &&
validate_type_params(state, stmt->v.ClassDef.type_params) &&
validate_exprs(state, stmt->v.ClassDef.bases, Load, 0) &&
validate_keywords(state, stmt->v.ClassDef.keywords) &&
validate_exprs(state, stmt->v.ClassDef.decorator_list, Load, 0);
break;
case Return_kind:
ret = !stmt->v.Return.value || validate_expr(state, stmt->v.Return.value, Load);
break;
case Delete_kind:
ret = validate_assignlist(state, stmt->v.Delete.targets, Del);
break;
case Assign_kind:
ret = validate_assignlist(state, stmt->v.Assign.targets, Store) &&
validate_expr(state, stmt->v.Assign.value, Load);
break;
case AugAssign_kind:
ret = validate_expr(state, stmt->v.AugAssign.target, Store) &&
validate_expr(state, stmt->v.AugAssign.value, Load);
break;
case AnnAssign_kind:
if (stmt->v.AnnAssign.target->kind != Name_kind &&
stmt->v.AnnAssign.simple) {
PyErr_SetString(PyExc_TypeError,
"AnnAssign with simple non-Name target");
return 0;
}
ret = validate_expr(state, stmt->v.AnnAssign.target, Store) &&
(!stmt->v.AnnAssign.value ||
validate_expr(state, stmt->v.AnnAssign.value, Load)) &&
validate_expr(state, stmt->v.AnnAssign.annotation, Load);
break;
case TypeAlias_kind:
ret = validate_expr(state, stmt->v.TypeAlias.name, Store) &&
validate_type_params(state, stmt->v.TypeAlias.type_params) &&
validate_expr(state, stmt->v.TypeAlias.value, Load);
break;
case For_kind:
ret = validate_expr(state, stmt->v.For.target, Store) &&
validate_expr(state, stmt->v.For.iter, Load) &&
validate_body(state, stmt->v.For.body, "For") &&
validate_stmts(state, stmt->v.For.orelse);
break;
case AsyncFor_kind:
ret = validate_expr(state, stmt->v.AsyncFor.target, Store) &&
validate_expr(state, stmt->v.AsyncFor.iter, Load) &&
validate_body(state, stmt->v.AsyncFor.body, "AsyncFor") &&
validate_stmts(state, stmt->v.AsyncFor.orelse);
break;
case While_kind:
ret = validate_expr(state, stmt->v.While.test, Load) &&
validate_body(state, stmt->v.While.body, "While") &&
validate_stmts(state, stmt->v.While.orelse);
break;
case If_kind:
ret = validate_expr(state, stmt->v.If.test, Load) &&
validate_body(state, stmt->v.If.body, "If") &&
validate_stmts(state, stmt->v.If.orelse);
break;
case With_kind:
if (!validate_nonempty_seq(stmt->v.With.items, "items", "With"))
return 0;
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)))
return 0;
}
ret = validate_body(state, stmt->v.With.body, "With");
break;
case AsyncWith_kind:
if (!validate_nonempty_seq(stmt->v.AsyncWith.items, "items", "AsyncWith"))
return 0;
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)))
return 0;
}
ret = validate_body(state, stmt->v.AsyncWith.body, "AsyncWith");
break;
case Match_kind:
if (!validate_expr(state, stmt->v.Match.subject, Load)
|| !validate_nonempty_seq(stmt->v.Match.cases, "cases", "Match")) {
return 0;
}
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))
|| !validate_body(state, m->body, "match_case")) {
return 0;
}
}
ret = 1;
break;
case Raise_kind:
if (stmt->v.Raise.exc) {
ret = validate_expr(state, stmt->v.Raise.exc, Load) &&
(!stmt->v.Raise.cause || validate_expr(state, stmt->v.Raise.cause, Load));
break;
}
if (stmt->v.Raise.cause) {
PyErr_SetString(PyExc_ValueError, "Raise with cause but no exception");
return 0;
}
ret = 1;
break;
case Try_kind:
if (!validate_body(state, stmt->v.Try.body, "Try"))
return 0;
if (!asdl_seq_LEN(stmt->v.Try.handlers) &&
!asdl_seq_LEN(stmt->v.Try.finalbody)) {
PyErr_SetString(PyExc_ValueError, "Try has neither except handlers nor finalbody");
return 0;
}
if (!asdl_seq_LEN(stmt->v.Try.handlers) &&
asdl_seq_LEN(stmt->v.Try.orelse)) {
PyErr_SetString(PyExc_ValueError, "Try has orelse but no except handlers");
return 0;
}
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 &&
!validate_expr(state, handler->v.ExceptHandler.type, Load)) ||
!validate_body(state, handler->v.ExceptHandler.body, "ExceptHandler"))
return 0;
}
ret = (!asdl_seq_LEN(stmt->v.Try.finalbody) ||
validate_stmts(state, stmt->v.Try.finalbody)) &&
(!asdl_seq_LEN(stmt->v.Try.orelse) ||
validate_stmts(state, stmt->v.Try.orelse));
break;
case TryStar_kind:
if (!validate_body(state, stmt->v.TryStar.body, "TryStar"))
return 0;
if (!asdl_seq_LEN(stmt->v.TryStar.handlers) &&
!asdl_seq_LEN(stmt->v.TryStar.finalbody)) {
PyErr_SetString(PyExc_ValueError, "TryStar has neither except handlers nor finalbody");
return 0;
}
if (!asdl_seq_LEN(stmt->v.TryStar.handlers) &&
asdl_seq_LEN(stmt->v.TryStar.orelse)) {
PyErr_SetString(PyExc_ValueError, "TryStar has orelse but no except handlers");
return 0;
}
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)) ||
!validate_body(state, handler->v.ExceptHandler.body, "ExceptHandler"))
return 0;
}
ret = (!asdl_seq_LEN(stmt->v.TryStar.finalbody) ||
validate_stmts(state, stmt->v.TryStar.finalbody)) &&
(!asdl_seq_LEN(stmt->v.TryStar.orelse) ||
validate_stmts(state, stmt->v.TryStar.orelse));
break;
case Assert_kind:
ret = validate_expr(state, stmt->v.Assert.test, Load) &&
(!stmt->v.Assert.msg || validate_expr(state, stmt->v.Assert.msg, Load));
break;
case Import_kind:
ret = validate_nonempty_seq(stmt->v.Import.names, "names", "Import");
break;
case ImportFrom_kind:
if (stmt->v.ImportFrom.level < 0) {
PyErr_SetString(PyExc_ValueError, "Negative ImportFrom level");
return 0;
}
ret = validate_nonempty_seq(stmt->v.ImportFrom.names, "names", "ImportFrom");
break;
case Global_kind:
ret = validate_nonempty_seq(stmt->v.Global.names, "names", "Global");
break;
case Nonlocal_kind:
ret = validate_nonempty_seq(stmt->v.Nonlocal.names, "names", "Nonlocal");
break;
case Expr_kind:
ret = validate_expr(state, stmt->v.Expr.value, Load);
break;
case AsyncFunctionDef_kind:
ret = validate_body(state, stmt->v.AsyncFunctionDef.body, "AsyncFunctionDef") &&
validate_type_params(state, stmt->v.AsyncFunctionDef.type_params) &&
validate_arguments(state, stmt->v.AsyncFunctionDef.args) &&
validate_exprs(state, stmt->v.AsyncFunctionDef.decorator_list, Load, 0) &&
(!stmt->v.AsyncFunctionDef.returns ||
validate_expr(state, stmt->v.AsyncFunctionDef.returns, Load));
break;
case Pass_kind:
case Break_kind:
case Continue_kind:
ret = 1;
break;
// No default case so compiler emits warning for unhandled cases
}
if (ret < 0) {
PyErr_SetString(PyExc_SystemError, "unexpected statement");
ret = 0;
}
state->recursion_depth--;
return ret;
}
static int
validate_stmts(struct validator *state, asdl_stmt_seq *seq)
{
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))
return 0;
}
else {
PyErr_SetString(PyExc_ValueError,
"None disallowed in statement list");
return 0;
}
}
return 1;
}
static int
validate_exprs(struct validator *state, asdl_expr_seq *exprs, expr_context_ty ctx, int null_ok)
{
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))
return 0;
}
else if (!null_ok) {
PyErr_SetString(PyExc_ValueError,
"None disallowed in expression list");
return 0;
}
}
return 1;
}
static int
validate_patterns(struct validator *state, asdl_pattern_seq *patterns, int star_ok)
{
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;
}
}
return 1;
}
static int
validate_typeparam(struct validator *state, type_param_ty tp)
{
VALIDATE_POSITIONS(tp);
int ret = -1;
switch (tp->kind) {
case TypeVar_kind:
ret = validate_name(tp->v.TypeVar.name) &&
(!tp->v.TypeVar.bound ||
validate_expr(state, tp->v.TypeVar.bound, Load));
break;
case ParamSpec_kind:
ret = validate_name(tp->v.ParamSpec.name);
break;
case TypeVarTuple_kind:
ret = validate_name(tp->v.TypeVarTuple.name);
break;
}
return ret;
}
static int
validate_type_params(struct validator *state, asdl_type_param_seq *tps)
{
Py_ssize_t i;
for (i = 0; i < asdl_seq_LEN(tps); i++) {
type_param_ty tp = asdl_seq_GET(tps, i);
if (tp) {
if (!validate_typeparam(state, tp))
return 0;
}
}
return 1;
}
/* See comments in symtable.c. */
#define COMPILER_STACK_FRAME_SCALE 2
int
_PyAST_Validate(mod_ty mod)
{
assert(!PyErr_Occurred());
int res = -1;
struct validator state;
PyThreadState *tstate;
int starting_recursion_depth;
/* Setup recursion depth check counters */
tstate = _PyThreadState_GET();
if (!tstate) {
return 0;
}
/* Be careful here to prevent overflow. */
int recursion_depth = Py_C_RECURSION_LIMIT - tstate->c_recursion_remaining;
starting_recursion_depth = recursion_depth * COMPILER_STACK_FRAME_SCALE;
state.recursion_depth = starting_recursion_depth;
state.recursion_limit = Py_C_RECURSION_LIMIT * COMPILER_STACK_FRAME_SCALE;
switch (mod->kind) {
case Module_kind:
res = validate_stmts(&state, mod->v.Module.body);
break;
case Interactive_kind:
res = validate_stmts(&state, mod->v.Interactive.body);
break;
case Expression_kind:
res = validate_expr(&state, mod->v.Expression.body, Load);
break;
case FunctionType_kind:
res = validate_exprs(&state, mod->v.FunctionType.argtypes, Load, /*null_ok=*/0) &&
validate_expr(&state, mod->v.FunctionType.returns, Load);
break;
// No default case so compiler emits warning for unhandled cases
}
if (res < 0) {
PyErr_SetString(PyExc_SystemError, "impossible module node");
return 0;
}
/* Check that the recursion depth counting balanced correctly */
if (res && state.recursion_depth != starting_recursion_depth) {
PyErr_Format(PyExc_SystemError,
"AST validator recursion depth mismatch (before=%d, after=%d)",
starting_recursion_depth, state.recursion_depth);
return 0;
}
return res;
}
PyObject *
_PyAST_GetDocString(asdl_stmt_seq *body)
{
if (!asdl_seq_LEN(body)) {
return NULL;
}
stmt_ty st = asdl_seq_GET(body, 0);
if (st->kind != Expr_kind) {
return NULL;
}
expr_ty e = st->v.Expr.value;
if (e->kind == Constant_kind && PyUnicode_CheckExact(e->v.Constant.value)) {
return e->v.Constant.value;
}
return NULL;
}
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