feat: skipDoubleRegistration configuration

README.md

@@ -154,7 +154,12 @@ You have to pass a factory function `func` that returns an instance of an implem
 ### Overwriting registrations
 
 If you try to register a type more than once you will fail with an assertion in debug mode because normally this is not needed and probably a bug.
-If you really have to overwrite a registration, then you can by setting the property `allowReassignment==true`.
+If you really have to overwrite a registration, then you can by setting the property `allowReassignment = true`.
+
+### Skip Double registrations
+
+If you try to register a type more than once and when `allowReassignment = false`  you will fail with an assertion in debug mode.
+If you want to just skip this double registration silently without an error, then you can by setting the property `skipDoubleRegistration = true`.
 
 ### Testing if a Singleton is already registered
 

lib/get_it.dart

@@ -7,6 +7,7 @@ import 'dart:collection';
 
 import 'package:async/async.dart';
 import 'package:collection/collection.dart' show IterableExtension;
+import 'package:meta/meta.dart';
 
 part 'get_it_impl.dart';
 
@@ -151,6 +152,11 @@ abstract class GetIt {
   /// If you really need to you can disable the asserts by setting[allowReassignment]= true
   bool allowReassignment = false;
 
+  /// By default it's throws error when [allowReassignment]= false. and trying to register same type
+  /// If you really need, you can disable the Asserts / Errror by setting[skipDoubleRegistration]= true
+  @visibleForTesting
+  bool skipDoubleRegistration = false;
+
   /// Till V7.6.7 GetIt didn't allow to register multiple instances of the same type.
   /// if you want to register multiple instances of the same type you can enable this
   /// and use `getAll()` to retrieve all instances of that parent type

lib/get_it_impl.dart

@@ -375,6 +375,12 @@ class _GetItImplementation implements GetIt {
   @override
   bool allowReassignment = false;
 
+  /// By default it's throws error when [allowReassignment]= false. and trying to register same type
+  /// If you really need, you can disable the Asserts / Errror by setting[skipDoubleRegistration]= true
+  @visibleForTesting
+  @override
+  bool skipDoubleRegistration = false;
+
   /// Is used by several other functions to retrieve the correct [_ServiceFactory]
   _ServiceFactory<T, dynamic, dynamic>?
       _findFirstFactoryByNameAndTypeOrNull<T extends Object>(
@@ -1027,19 +1033,31 @@ class _GetItImplementation implements GetIt {
       if (instanceName != null) {
         throwIf(
           existingTypeRegistration.namedFactories.containsKey(instanceName) &&
-              !allowReassignment,
+              !allowReassignment &&
+              !skipDoubleRegistration,
           ArgumentError(
             'Object/factory with name $instanceName and '
             'type $T is already registered inside GetIt. ',
           ),
         );
+
+        /// skip double registration
+        if (skipDoubleRegistration && !allowReassignment) {
+          return;
+        }
       } else {
         if (existingTypeRegistration.factories.isNotEmpty) {
           throwIfNot(
             allowReassignment ||
-                GetIt.allowRegisterMultipleImplementationsOfoneType,
+                GetIt.allowRegisterMultipleImplementationsOfoneType ||
+                skipDoubleRegistration,
             ArgumentError('Type $T is already registered inside GetIt. '),
           );
+
+          /// skip double registration
+          if (skipDoubleRegistration && !allowReassignment) {
+            return;
+          }
         }
       }
     }

pubspec.yaml

@@ -10,6 +10,7 @@ environment:
 dependencies:
   async: ^2.11.0
   collection: ^1.17.1
+  meta: ^1.11.0
 
 dev_dependencies:
   lint: ^2.1.2

test/skip_double_registration_test.dart

@@ -0,0 +1,57 @@
+import 'package:get_it/get_it.dart';
+import 'package:test/test.dart';
+
+void main() {
+  test(' Throws ArgumentError ', () async {
+    final getIt = GetIt.instance;
+    getIt.allowReassignment = false;
+    getIt.skipDoubleRegistration = false;
+    getIt.reset();
+    getIt.registerSingleton<DataStore>(MockDataStore());
+
+    expect(
+      () => getIt.registerSingleton<DataStore>(RemoteDataStore()),
+      throwsArgumentError,
+    );
+  });
+
+  test(' replaces dependency safely ', () async {
+    final getIt = GetIt.instance;
+    getIt.reset();
+    getIt.allowReassignment = true;
+    getIt.skipDoubleRegistration = false;
+    getIt.registerSingleton<DataStore>(MockDataStore());
+    getIt.registerSingleton<DataStore>(RemoteDataStore());
+
+    expect(getIt<DataStore>(), isA<RemoteDataStore>());
+  });
+
+  test(' Ignores Double registration error ', () async {
+    final getIt = GetIt.instance;
+    getIt.reset();
+    getIt.allowReassignment = false;
+    getIt.skipDoubleRegistration = true;
+    getIt.registerSingleton<DataStore>(MockDataStore());
+    final remoteDataStore = RemoteDataStore();
+    getIt.registerSingleton<DataStore>(remoteDataStore);
+
+    expect(getIt<DataStore>(), isA<MockDataStore>());
+  });
+
+  test(' does not care about [skipDoubleRegistration] varibale   ', () async {
+    final getIt = GetIt.instance;
+    getIt.reset();
+    getIt.allowReassignment = true;
+    getIt.skipDoubleRegistration = true;
+    getIt.registerSingleton<DataStore>(MockDataStore());
+    getIt.registerSingleton<DataStore>(RemoteDataStore());
+
+    expect(getIt<DataStore>(), isA<RemoteDataStore>());
+  });
+}
+
+abstract class DataStore {}
+
+class RemoteDataStore implements DataStore {}
+
+class MockDataStore implements DataStore {}