support latest release of package:graphs

bin/multipack.dart

@@ -7,8 +7,10 @@ import "package:multipack/package.dart";
 void main(List<String> arguments) async {
   final dependencyGraph = await getPackageGraph(Directory.current);
 
-  final orderedPackages =
-      dependencyGraph.sortedTopologicalOrdering!.toList().reversed.toList();
+  final topologicalGraph =
+      dependencyGraph.sortedTopologicalOrdering ?? <Package>{};
+
+  final orderedPackages = List.of(topologicalGraph).reversed.toList();
 
   final packageNames = orderedPackages
       .map(

lib/commands/pubspec/hard_override.dart

@@ -19,7 +19,9 @@ class HardOverrideCommand extends MultipackCommand {
   FutureOr<int> runOnPackage(Package package) async {
     try {
       MapEntry<String, DependencyReference> map(
-          String key, DependencyReference ref,) {
+        String key,
+        DependencyReference ref,
+      ) {
         if (ref is! HostedReference) return MapEntry(key, ref);
 
         final localPackage = packages.firstWhereOrNull(

pubspec.yaml

@@ -1,9 +1,9 @@
 name: multipack
-description: A tool for monorepo management. Link local packages and execute commands in topological order.
-version: 0.3.1
+version: 0.3.2
 homepage: https://github.com/gql-dart/multipack
-environment:
-  sdk: '>=2.12.0 <4.0.0'
+description: A tool for monorepo management. Link local packages and execute commands in topological order.
+environment: 
+  sdk: '>=3.0.0 <4.0.0'
 dependencies: 
   ansicolor: ^2.0.0
   args: ^2.0.0
@@ -14,7 +14,7 @@ dependencies:
   pub_semver: ^2.0.0
   pubspec: ^2.0.0
 
-dev_dependencies: 
+dev_dependencies:
   lint: ^2.0.0
 executables:
   multipack: null