python · berkerpeksag · Feb 26, 2017 · Feb 26, 2017
diff --git a/Lib/sqlite3/test/transactions.py b/Lib/sqlite3/test/transactions.py
@@ -179,6 +179,15 @@ def CheckDdlDoesNotAutostartTransaction(self):
        result = self.con.execute("select * from test").fetchall()
        self.assertEqual(result, [])

+    def CheckImmediateTransactionalDDL(self):
+        # You can achieve transactional DDL by issuing a BEGIN
+        # statement manually.
+        self.con.execute("begin immediate")
+        self.con.execute("create table test(i)")
+        self.con.rollback()
+        with self.assertRaises(sqlite.OperationalError):
+            self.con.execute("select * from test")
+
    def CheckTransactionalDDL(self):
        # You can achieve transactional DDL by issuing a BEGIN
        # statement manually.

diff --git a/Misc/NEWS b/Misc/NEWS
@@ -69,6 +69,9 @@ Extension Modules
 Library
 -------

+- bpo-28518: Start a transaction implicitly before a DML statement.
+  Patch by Aviv Palivoda.
+
 - bpo-29532: Altering a kwarg dictionary passed to functools.partial()
  no longer affects a partial object after creation.


diff --git a/Modules/_sqlite/cursor.c b/Modules/_sqlite/cursor.c
@@ -511,10 +511,9 @@ PyObject* _pysqlite_query_execute(pysqlite_Cursor* self, int multiple, PyObject*
    pysqlite_statement_reset(self->statement);
    pysqlite_statement_mark_dirty(self->statement);

-    /* For backwards compatibility reasons, do not start a transaction if a
-       DDL statement is encountered.  If anybody wants transactional DDL,
-       they can issue a BEGIN statement manually. */
-    if (self->connection->begin_statement && !sqlite3_stmt_readonly(self->statement->st) && !self->statement->is_ddl) {
+    /* We start a transaction implicitly before a DML statement.
+       SELECT is the only exception. See #9924. */
+    if (self->connection->begin_statement && self->statement->is_dml) {
        if (sqlite3_get_autocommit(self->connection->db)) {
            result = _pysqlite_connection_begin(self->connection);
            if (!result) {
@@ -609,7 +608,7 @@ PyObject* _pysqlite_query_execute(pysqlite_Cursor* self, int multiple, PyObject*
            }
        }

-        if (!sqlite3_stmt_readonly(self->statement->st)) {
+        if (self->statement->is_dml) {
            self->rowcount += (long)sqlite3_changes(self->connection->db);
        } else {
            self->rowcount= -1L;

diff --git a/Modules/_sqlite/statement.c b/Modules/_sqlite/statement.c
@@ -73,8 +73,9 @@ int pysqlite_statement_create(pysqlite_Statement* self, pysqlite_Connection* con
    Py_INCREF(sql);
    self->sql = sql;

-    /* determine if the statement is a DDL statement */
-    self->is_ddl = 0;
+    /* Determine if the statement is a DML statement.
+       SELECT is the only exception. See #9924. */
+    self->is_dml = 0;
    for (p = sql_cstr; *p != 0; p++) {
        switch (*p) {
            case ' ':
@@ -84,9 +85,10 @@ int pysqlite_statement_create(pysqlite_Statement* self, pysqlite_Connection* con
                continue;
        }

-        self->is_ddl = (PyOS_strnicmp(p, "create ", 7) == 0)
-                    || (PyOS_strnicmp(p, "drop ", 5) == 0)
-                    || (PyOS_strnicmp(p, "reindex ", 8) == 0);
+        self->is_dml = (PyOS_strnicmp(p, "insert ", 7) == 0)
+                    || (PyOS_strnicmp(p, "update ", 7) == 0)
+                    || (PyOS_strnicmp(p, "delete ", 7) == 0)
+                    || (PyOS_strnicmp(p, "replace ", 8) == 0);
        break;
    }


diff --git a/Modules/_sqlite/statement.h b/Modules/_sqlite/statement.h
@@ -38,7 +38,7 @@ typedef struct
    sqlite3_stmt* st;
    PyObject* sql;
    int in_use;
-    int is_ddl;
+    int is_dml;
    PyObject* in_weakreflist; /* List of weak references */
 } pysqlite_Statement;