Commit transaction after early return (#63)

* add test case to demonstrate early (non-labeled) return from transaction
* commit connection in finally block to support inline return

src/main/kotlin/kotliquery/Session.kt

@@ -304,17 +304,20 @@ open class Session(
     }
 
     inline fun <A> transaction(operation: (TransactionalSession) -> A): A {
+        var shouldCommit = true
         try {
             connection.begin()
             transactional = true
             val tx = TransactionalSession(connection, returnGeneratedKeys, autoGeneratedKeys, strict)
-            val result: A = operation.invoke(tx)
-            connection.commit()
-            return result
+            return operation.invoke(tx)
         } catch (e: Exception) {
+            shouldCommit = false
             connection.rollback()
             throw e
         } finally {
+            if (shouldCommit) {
+                connection.commit()
+            }
             transactional = false
         }
     }

src/test/kotlin/kotliquery/UsageTest.kt

@@ -162,6 +162,28 @@ class UsageTest {
         }
     }
 
+    @Test
+    fun transactionWithNonLabeledReturnGetsCommitted() {
+        fun insertAndReturn(session: Session, name: String) {
+            session.transaction { tx ->
+                tx.run(queryOf(insert, name, Date()).asUpdate)
+                // Non-labeled return
+                return
+            }
+        }
+
+        using(sessionOf(testDataSource)) { session ->
+            insertAndReturn(session, "Chris")
+        }
+
+        using(sessionOf(testDataSource)) { session ->
+            val membersCount = session.single(queryOf("select count(*) as count from members")) { row ->
+                row.int("count")
+            }
+            assertEquals(1, membersCount)
+        }
+    }
+
     @Test
     fun testHikariCPUsage() {