From 7e19bb2a470465b3efec2b8cdfd0f204f949f759 Mon Sep 17 00:00:00 2001
From: Tobe O <thosakwe@gmail.com>
Date: Sat, 17 Aug 2019 17:53:23 -0400
Subject: [PATCH] Add a required `QueryExecutor` argument to `transaction`
 callbacks.

---
 angel_orm/CHANGELOG.md                |  2 ++
 angel_orm/example/main.dart           |  2 +-
 angel_orm/lib/src/query.dart          |  4 ++--
 angel_orm/lib/src/query_executor.dart | 11 +++++++++--
 4 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/angel_orm/CHANGELOG.md b/angel_orm/CHANGELOG.md
index 3de6a208..1b4e73e8 100644
--- a/angel_orm/CHANGELOG.md
+++ b/angel_orm/CHANGELOG.md
@@ -1,6 +1,8 @@
 # 2.1.0
 * Split the formerly 600+ line `src/query.dart` up into
 separate files.
+* **BREAKING**: Add a required `QueryExecutor` argument to `transaction`
+callbacks.
 
 # 2.0.1
 * Apply `package:pedantic` fixes.
diff --git a/angel_orm/example/main.dart b/angel_orm/example/main.dart
index 719500f6..fbf6866d 100644
--- a/angel_orm/example/main.dart
+++ b/angel_orm/example/main.dart
@@ -34,7 +34,7 @@ class _FakeExecutor extends QueryExecutor {
   }
 
   @override
-  Future<T> transaction<T>(FutureOr<T> Function() f) {
+  Future<T> transaction<T>(FutureOr<T> Function(QueryExecutor) f) {
     throw UnsupportedError('Transactions are not supported.');
   }
 }
diff --git a/angel_orm/lib/src/query.dart b/angel_orm/lib/src/query.dart
index 5427ef18..0a56b015 100644
--- a/angel_orm/lib/src/query.dart
+++ b/angel_orm/lib/src/query.dart
@@ -263,9 +263,9 @@ abstract class Query<T, Where extends QueryWhere> extends QueryBase<T> {
               fields.map(adornWithTableName).toList())
           .then((it) => it.map(deserialize).toList());
     } else {
-      return executor.transaction(() async {
+      return executor.transaction((tx) async {
         // TODO: Can this be done with just *one* query?
-        var existing = await get(executor);
+        var existing = await get(tx);
         //var sql = compile(preamble: 'SELECT $tableName.id', withFields: false);
         return executor
             .query(tableName, sql, substitutionValues)
diff --git a/angel_orm/lib/src/query_executor.dart b/angel_orm/lib/src/query_executor.dart
index 558a4d9d..ec6448c0 100644
--- a/angel_orm/lib/src/query_executor.dart
+++ b/angel_orm/lib/src/query_executor.dart
@@ -11,6 +11,13 @@ abstract class QueryExecutor {
       String tableName, String query, Map<String, dynamic> substitutionValues,
       [List<String> returningFields]);
 
-  /// Begins a database transaction.
-  Future<T> transaction<T>(FutureOr<T> f());
+  /// Enters a database transaction, performing the actions within,
+  /// and returning the results of [f].
+  ///
+  /// If [f] fails, the transaction will be rolled back, and the
+  /// responsible exception will be re-thrown.
+  /// 
+  /// Whether nested transactions are supported depends on the
+  /// underlying driver.
+  Future<T> transaction<T>(FutureOr<T> Function(QueryExecutor) f);
 }