bpo-45138: Expand traced SQL statements in `sqlite3` trace callback (GH-28240)

1 files changed, 35 insertions, 14 deletions

diff --git a/Modules/_sqlite/connection.c b/Modules/_sqlite/connection.c
index e4b8ecb..511e8a2 100644
--- a/Modules/_sqlite/connection.c
+++ b/Modules/_sqlite/connection.c
@@ -1079,11 +1079,10 @@ progress_callback(void *ctx)
  * to ensure future compatibility.
  */
 static int
-trace_callback(unsigned int type, void *ctx, void *prepared_statement,
-               void *statement_string)
+trace_callback(unsigned int type, void *ctx, void *stmt, void *sql)
 #else
 static void
-trace_callback(void *ctx, const char *statement_string)
+trace_callback(void *ctx, const char *sql)
 #endif
 {
 #ifdef HAVE_TRACE_V2
@@ -1094,24 +1093,46 @@ trace_callback(void *ctx, const char *statement_string)
 
     PyGILState_STATE gilstate = PyGILState_Ensure();
 
-    PyObject *py_statement = NULL;
-    PyObject *ret = NULL;
-    py_statement = PyUnicode_DecodeUTF8(statement_string,
-            strlen(statement_string), "replace");
     assert(ctx != NULL);
+    PyObject *py_statement = NULL;
+#ifdef HAVE_TRACE_V2
+    assert(stmt != NULL);
+    const char *expanded_sql = sqlite3_expanded_sql((sqlite3_stmt *)stmt);
+    if (expanded_sql == NULL) {
+        sqlite3 *db = sqlite3_db_handle((sqlite3_stmt *)stmt);
+        if (sqlite3_errcode(db) == SQLITE_NOMEM) {
+            (void)PyErr_NoMemory();
+            goto exit;
+        }
+
+        pysqlite_state *state = ((callback_context *)ctx)->state;
+        assert(state != NULL);
+        PyErr_SetString(state->DataError,
+                        "Expanded SQL string exceeds the maximum string "
+                        "length");
+        print_or_clear_traceback((callback_context *)ctx);
+
+        // Fall back to unexpanded sql
+        py_statement = PyUnicode_FromString((const char *)sql);
+    }
+    else {
+        py_statement = PyUnicode_FromString(expanded_sql);
+        sqlite3_free((void *)expanded_sql);
+    }
+#else
+    py_statement = PyUnicode_FromString(sql);
+#endif
     if (py_statement) {
         PyObject *callable = ((callback_context *)ctx)->callable;
-        ret = PyObject_CallOneArg(callable, py_statement);
+        PyObject *ret = PyObject_CallOneArg(callable, py_statement);
         Py_DECREF(py_statement);
+        Py_XDECREF(ret);
     }
 
-    if (ret) {
-        Py_DECREF(ret);
-    }
-    else {
-        print_or_clear_traceback(ctx);
+exit:
+    if (PyErr_Occurred()) {
+        print_or_clear_traceback((callback_context *)ctx);
     }
-
     PyGILState_Release(gilstate);
 #ifdef HAVE_TRACE_V2
     return 0;