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gh-93351: Ensure the position information in AST nodes created by the parser is always consistent#93352

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Merged
pablogsal merged 2 commits into from
May 30, 2022
Merged

gh-93351: Ensure the position information in AST nodes created by the parser is always consistent #93352

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dde7b64
gh-93351: Validate the position information when compiling AST nodes
pablogsal May 30, 2022
8d865bf
fixup! gh-93351: Validate the position information when compiling AST…
pablogsal May 30, 2022
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27 changes: 27 additions & 0 deletions Lib/test/test_ast.py
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Original file line numberDiff line numberDiff line change
Expand Up@@ -335,6 +335,33 @@ def test_ast_validation(self):
for snippet in snippets_to_validate:
tree = ast.parse(snippet)
compile(tree, '<string>', 'exec')

def test_invalid_position_information(self):
invalid_linenos = [
(10, 1), (-10, -11), (10, -11), (-5, -2), (-5, 1)
]

for lineno, end_lineno in invalid_linenos:
with self.subTest(f"Check invalid linenos {lineno}:{end_lineno}"):
snippet = "a = 1"
tree = ast.parse(snippet)
tree.body[0].lineno = lineno
tree.body[0].end_lineno = end_lineno
with self.assertRaises(ValueError):
compile(tree, '<string>', 'exec')

invalid_col_offsets = [
(10, 1), (-10, -11), (10, -11), (-5, -2), (-5, 1)
]
for col_offset, end_col_offset in invalid_col_offsets:
with self.subTest(f"Check invalid col_offset {col_offset}:{end_col_offset}"):
snippet = "a = 1"
tree = ast.parse(snippet)
tree.body[0].col_offset = col_offset
tree.body[0].end_col_offset = end_col_offset
with self.assertRaises(ValueError):
compile(tree, '<string>', 'exec')


def test_slice(self):
slc = ast.parse("x[::]").body[0].value.slice
Expand Down
26 changes: 26 additions & 0 deletions Python/ast.c
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Original file line numberDiff line numberDiff line change
Expand Up@@ -22,6 +22,27 @@ 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);

#define VALIDATE_POSITIONS(node) \
if (node->lineno > node->end_lineno) { \
PyErr_Format(PyExc_ValueError, \
"line %d-%d is not a valid range", \
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, \
"line %d-%d, column %d-%d is not a valid range", \
node->lineno, node->end_lineno, node->col_offset, node->end_col_offset); \
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)
{
Expand DownExpand Up@@ -75,6 +96,7 @@ validate_args(struct validator *state, asdl_arg_seq *args)
Py_ssize_t i;
for (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;
}
Expand DownExpand Up@@ -183,6 +205,7 @@ validate_constant(struct validator *state, PyObject *value)
static int
validate_expr(struct validator *state, expr_ty exp, expr_context_ty ctx)
{
VALIDATE_POSITIONS(exp);
int ret = -1;
if (++state->recursion_depth > state->recursion_limit) {
PyErr_SetString(PyExc_RecursionError,
Expand DownExpand Up@@ -505,6 +528,7 @@ validate_capture(PyObject *name)
static int
validate_pattern(struct validator *state, pattern_ty p, int star_ok)
{
VALIDATE_POSITIONS(p);
int ret = -1;
if (++state->recursion_depth > state->recursion_limit) {
PyErr_SetString(PyExc_RecursionError,
Expand DownExpand Up@@ -674,6 +698,7 @@ validate_body(struct validator *state, asdl_stmt_seq *body, const char *owner)
static int
validate_stmt(struct validator *state, stmt_ty stmt)
{
VALIDATE_POSITIONS(stmt);
int ret = -1;
Py_ssize_t i;
if (++state->recursion_depth > state->recursion_limit) {
Expand DownExpand Up@@ -807,6 +832,7 @@ validate_stmt(struct validator *state, stmt_ty stmt)
}
for (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"))
Expand Down