Allow resuming transactions after caught errors.

Author: rkistner

lib/src/sqlite_connection_impl.dart

@@ -269,10 +269,8 @@ Future<void> _sqliteConnectionIsolateInner(_SqliteConnectionParams params,
   server.open((data) async {
     if (data is _SqliteIsolateClose) {
       if (txId != null) {
-        try {
+        if (!db.autocommit) {
           db.execute('ROLLBACK');
-        } catch (e) {
-          // Ignore
         }
         txId = null;
         txError = null;
@@ -290,7 +288,8 @@ Future<void> _sqliteConnectionIsolateInner(_SqliteConnectionParams params,
         txId = data.ctxId;
       } else if (txId != null && txId != data.ctxId) {
         // Locks should prevent this from happening
-        throw AssertionError('Mixed transactions: $txId and ${data.ctxId}');
+        throw sqlite.SqliteException(
+            0, 'Mixed transactions: $txId and ${data.ctxId}');
       } else if (data.sql == 'ROLLBACK') {
         // This is the only valid way to clear an error
         txError = null;
@@ -307,7 +306,13 @@ Future<void> _sqliteConnectionIsolateInner(_SqliteConnectionParams params,
         return result;
       } catch (err) {
         if (txId != null) {
-          txError = err;
+          if (db.autocommit) {
+            // Transaction rolled back
+            txError = sqlite.SqliteException(0,
+                'Transaction rolled back by earlier statement: ${err.toString()}');
+          } else {
+            // Recoverable error
+          }
         }
         rethrow;
       }

pubspec.yaml

@@ -6,7 +6,7 @@ environment:
   sdk: '>=2.19.1 <4.0.0'
 
 dependencies:
-  sqlite3: '>=1.10.1 <3.0.0'
+  sqlite3: '^2.3.0'
   async: ^2.10.0
   collection: ^1.17.0
 

test/basic_test.dart

@@ -222,18 +222,30 @@ void main() {
       await createTables(db);
 
       var tp = db.writeTransaction((tx) async {
-        tx.execute('INSERT INTO test_data(description) VALUES(?)', ['test1']);
-        tx.execute('INSERT INTO test_data(description) VALUES(?)', ['test2']);
-        ignore(tx.execute('INSERT INTO test_data(description) VALUES(json(?))',
-            ['test3'])); // Errors
-        // Will not be executed because of the above error
+        tx.execute(
+            'INSERT OR ROLLBACK INTO test_data(id, description) VALUES(?, ?)',
+            [1, 'test1']);
+        tx.execute(
+            'INSERT OR ROLLBACK INTO test_data(id, description) VALUES(?, ?)',
+            [2, 'test2']);
         ignore(tx.execute(
-            'INSERT INTO test_data(description) VALUES(?) RETURNING *',
-            ['test4']));
+            'INSERT OR ROLLBACK INTO test_data(id, description) VALUES(?, ?)',
+            [2, 'test3'])); // Errors
+
+        // Will not be executed because of the above rollback
+        ignore(tx.execute(
+            'INSERT OR ROLLBACK INTO test_data(id, description) VALUES(?, ?)',
+            [4, 'test4']));
       });
 
       // The error propagates up to the transaction
-      await expectLater(tp, throwsA((e) => e is sqlite.SqliteException));
+      await expectLater(
+          tp,
+          throwsA((e) =>
+              e is sqlite.SqliteException &&
+              e.message
+                  .contains('Transaction rolled back by earlier statement') &&
+              e.message.contains('UNIQUE constraint failed')));
 
       expect(await db.get('SELECT count() count FROM test_data'),
           equals({'count': 0}));
@@ -321,6 +333,27 @@ void main() {
       });
       expect(computed, equals(5));
     });
+
+    test('should allow resuming transaction after errors', () async {
+      final db = await setupDatabase(path: path);
+      await createTables(db);
+      await db.writeTransaction((tx) async {
+        var caught = false;
+        try {
+          // This error does not rollback the transaction
+          await tx.execute('NOT A VALID STATEMENT');
+        } catch (e) {
+          // Ignore
+          caught = true;
+        }
+        expect(caught, equals(true));
+
+        final rs = await tx.execute(
+            'INSERT INTO test_data(description) VALUES(?) RETURNING description',
+            ['Test Data']);
+        expect(rs.rows[0], equals(['Test Data']));
+      });
+    });
   });
 }