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gh-139327: consolidate sqlite3_finalize and sqlite3_reset usages #139329

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Merged
merged 5 commits into from
Oct 15, 2025
Merged

gh-139327: consolidate sqlite3_finalize and sqlite3_reset usages #139329

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b50713c
consolidate `sqlite3_finalize` and `sqlite3_reset` usages
picnixz Sep 26, 2025
a1b9eaa
reset_ok -> reset_rc
picnixz Oct 5, 2025
5653512
check that `blob_error` set an exception
picnixz Oct 5, 2025
6a3a708
assert that `PyErr_SetString` is not called with an active exception
picnixz Oct 5, 2025
44f72e9
avoid a possible double-free at the cost of a possible leak
picnixz Oct 5, 2025
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4 changes: 3 additions & 1 deletion Modules/_sqlite/blob.c
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Original file line number Diff line number Diff line change
Expand Up @@ -118,7 +118,9 @@ static void
blob_seterror(pysqlite_Blob *self, int rc)
{
assert(self->connection != NULL);
set_error_from_db(self->connection->state, self->connection->db);
assert(rc != SQLITE_OK);
set_error_from_code(self->connection->state, rc);
assert(PyErr_Occurred());
}

static PyObject *
Expand Down
101 changes: 92 additions & 9 deletions Modules/_sqlite/cursor.c
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Original file line number Diff line number Diff line change
Expand Up @@ -58,6 +58,41 @@ check_cursor_locked(pysqlite_Cursor *cur)
return 1;
}

static pysqlite_state *
get_module_state_by_cursor(pysqlite_Cursor *cursor)
{
if (cursor->connection != NULL && cursor->connection->state != NULL) {
return cursor->connection->state;
}
return pysqlite_get_state_by_type(Py_TYPE(cursor));
}

static void
cursor_sqlite3_internal_error(pysqlite_Cursor *cursor,
const char *error_message,
int chain_exceptions)
{
pysqlite_state *state = get_module_state_by_cursor(cursor);
if (chain_exceptions) {
assert(PyErr_Occurred());
PyObject *exc = PyErr_GetRaisedException();
PyErr_SetString(state->InternalError, error_message);
_PyErr_ChainExceptions1(exc);
}
else {
assert(!PyErr_Occurred());
PyErr_SetString(state->InternalError, error_message);
}
}

static void
cursor_cannot_reset_stmt_error(pysqlite_Cursor *cursor, int chain_exceptions)
{
cursor_sqlite3_internal_error(cursor,
"cannot reset statement",
chain_exceptions);
}

/*[clinic input]
module _sqlite3
class _sqlite3.Cursor "pysqlite_Cursor *" "clinic_state()->CursorType"
Expand Down Expand Up @@ -173,8 +208,12 @@ cursor_clear(PyObject *op)
Py_CLEAR(self->row_factory);
if (self->statement) {
/* Reset the statement if the user has not closed the cursor */
stmt_reset(self->statement);
int rc = stmt_reset(self->statement);
Py_CLEAR(self->statement);
if (rc != SQLITE_OK) {
cursor_cannot_reset_stmt_error(self, 0);
PyErr_FormatUnraisable("Exception ignored in cursor_clear()");
}
}

return 0;
Expand Down Expand Up @@ -834,7 +873,9 @@ _pysqlite_query_execute(pysqlite_Cursor* self, int multiple, PyObject* operation

if (self->statement) {
// Reset pending statements on this cursor.
(void)stmt_reset(self->statement);
if (stmt_reset(self->statement) != SQLITE_OK) {
goto reset_failure;
}
}

PyObject *stmt = get_statement_from_cache(self, operation);
Expand All @@ -858,7 +899,9 @@ _pysqlite_query_execute(pysqlite_Cursor* self, int multiple, PyObject* operation
}
}

(void)stmt_reset(self->statement);
if (stmt_reset(self->statement) != SQLITE_OK) {
goto reset_failure;
}
self->rowcount = self->statement->is_dml ? 0L : -1L;

/* We start a transaction implicitly before a DML statement.
Expand Down Expand Up @@ -940,7 +983,9 @@ _pysqlite_query_execute(pysqlite_Cursor* self, int multiple, PyObject* operation
if (self->statement->is_dml) {
self->rowcount += (long)sqlite3_changes(self->connection->db);
}
stmt_reset(self->statement);
if (stmt_reset(self->statement) != SQLITE_OK) {
goto reset_failure;
}
}
Py_XDECREF(parameters);
}
Expand All @@ -965,8 +1010,15 @@ _pysqlite_query_execute(pysqlite_Cursor* self, int multiple, PyObject* operation

if (PyErr_Occurred()) {
if (self->statement) {
(void)stmt_reset(self->statement);
sqlite3 *db = sqlite3_db_handle(self->statement->st);
int sqlite3_state = sqlite3_errcode(db);
// stmt_reset() may return a previously set exception,
// either triggered because of Python or sqlite3.
rc = stmt_reset(self->statement);
Py_CLEAR(self->statement);
if (sqlite3_state == SQLITE_OK && rc != SQLITE_OK) {
cursor_cannot_reset_stmt_error(self, 1);
}
}
self->rowcount = -1L;
return NULL;
Expand All @@ -975,6 +1027,20 @@ _pysqlite_query_execute(pysqlite_Cursor* self, int multiple, PyObject* operation
Py_CLEAR(self->statement);
}
return Py_NewRef((PyObject *)self);

reset_failure:
/* suite to execute when stmt_reset() failed and no exception is set */
assert(!PyErr_Occurred());

Py_XDECREF(parameters);
Py_XDECREF(parameters_iter);
Py_XDECREF(parameters_list);

self->locked = 0;
self->rowcount = -1L;
Py_CLEAR(self->statement);
cursor_cannot_reset_stmt_error(self, 0);
return NULL;
}

/*[clinic input]
Expand Down Expand Up @@ -1117,14 +1183,20 @@ pysqlite_cursor_iternext(PyObject *op)
if (self->statement->is_dml) {
self->rowcount = (long)sqlite3_changes(self->connection->db);
}
(void)stmt_reset(self->statement);
rc = stmt_reset(self->statement);
Py_CLEAR(self->statement);
if (rc != SQLITE_OK) {
goto reset_failure;
}
}
else if (rc != SQLITE_ROW) {
set_error_from_db(self->connection->state, self->connection->db);
(void)stmt_reset(self->statement);
rc = set_error_from_db(self->connection->state, self->connection->db);
int reset_rc = stmt_reset(self->statement);
Py_CLEAR(self->statement);
Py_DECREF(row);
if (rc == SQLITE_OK && reset_rc != SQLITE_OK) {
goto reset_failure;
}
return NULL;
}
if (!Py_IsNone(self->row_factory)) {
Expand All @@ -1134,6 +1206,10 @@ pysqlite_cursor_iternext(PyObject *op)
Py_SETREF(row, new_row);
}
return row;

reset_failure:
cursor_cannot_reset_stmt_error(self, 0);
return NULL;
}

/*[clinic input]
Expand Down Expand Up @@ -1292,8 +1368,15 @@ pysqlite_cursor_close_impl(pysqlite_Cursor *self)
}

if (self->statement) {
(void)stmt_reset(self->statement);
int rc = stmt_reset(self->statement);
// Force self->statement to be NULL even if stmt_reset() may have
// failed to avoid a possible double-free if someone calls close()
// twice as a leak here would be better than a double-free.
Py_CLEAR(self->statement);
if (rc != SQLITE_OK) {
cursor_cannot_reset_stmt_error(self, 0);
return NULL;
}
}

self->closed = 1;
Expand Down
17 changes: 14 additions & 3 deletions Modules/_sqlite/statement.c
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Original file line number Diff line number Diff line change
Expand Up @@ -96,7 +96,12 @@ pysqlite_statement_create(pysqlite_Connection *connection, PyObject *sql)
return self;

error:
(void)sqlite3_finalize(stmt);
assert(PyErr_Occurred());
if (sqlite3_finalize(stmt) != SQLITE_OK) {
PyObject *exc = PyErr_GetRaisedException();
PyErr_SetString(connection->InternalError, "cannot finalize statement");
_PyErr_ChainExceptions1(exc);
}
return NULL;
}

Expand All @@ -107,10 +112,16 @@ stmt_dealloc(PyObject *op)
PyTypeObject *tp = Py_TYPE(self);
PyObject_GC_UnTrack(op);
if (self->st) {
int rc;
Py_BEGIN_ALLOW_THREADS
sqlite3_finalize(self->st);
rc = sqlite3_finalize(self->st);
Py_END_ALLOW_THREADS
self->st = 0;
self->st = NULL;
if (rc != SQLITE_OK) {
pysqlite_state *state = PyType_GetModuleState(Py_TYPE(op));
PyErr_SetString(state->InternalError, "cannot finalize statement");
PyErr_FormatUnraisable("Exception ignored in stmt_dealloc()");
}
}
tp->tp_free(self);
Py_DECREF(tp);
Expand Down
5 changes: 3 additions & 2 deletions Modules/_sqlite/util.c
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Expand Up @@ -135,21 +135,22 @@ set_error_from_code(pysqlite_state *state, int code)
/**
* Checks the SQLite error code and sets the appropriate DB-API exception.
*/
void
int
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@encukou encukou Sep 30, 2025

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In blob.c, should blob_seterror assert that set_error_from_db didn't return SQLITE_OK?
Same for when connection.c and the files changed here call blob_seterror without checking the result.

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@picnixz picnixz Oct 5, 2025

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Oh I missed the blob stuff. I think we should also assert this indeed.

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@picnixz picnixz Oct 5, 2025

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Also, I think there was an API misuse here. We pass rc but we never use it. I think we were meant to use set_error_from_code instead.

set_error_from_db(pysqlite_state *state, sqlite3 *db)
{
int errorcode = sqlite3_errcode(db);
PyObject *exc_class = get_exception_class(state, errorcode);
if (exc_class == NULL) {
// No new exception need be raised.
return;
return SQLITE_OK;
}

/* Create and set the exception. */
int extended_errcode = sqlite3_extended_errcode(db);
// sqlite3_errmsg() always returns an UTF-8 encoded message
const char *errmsg = sqlite3_errmsg(db);
raise_exception(exc_class, extended_errcode, errmsg);
return errorcode;
}

#ifdef WORDS_BIGENDIAN
Expand Down
2 changes: 1 addition & 1 deletion Modules/_sqlite/util.h
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Expand Up @@ -31,7 +31,7 @@
/**
* Checks the SQLite error code and sets the appropriate DB-API exception.
*/
void set_error_from_db(pysqlite_state *state, sqlite3 *db);
int set_error_from_db(pysqlite_state *state, sqlite3 *db);
void set_error_from_code(pysqlite_state *state, int code);

sqlite_int64 _pysqlite_long_as_int64(PyObject * value);
Expand Down
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