Restore ordering of jobs to what it was before (#450)

Restore ordering with explicit secondary sort by insertion order

Author: jakemac53

.github/workflows/dart.yml

@@ -1,3 +1,8 @@
+## 6.5.6
+
+- Restore the previous ordering behavior for jobs by using a secondary sort
+  based on the insertion order (this matches the listed configuration order).
+
 ## 6.5.5
 
 - Add the pub package topics `tool` and `repository-management`.

mono_repo/CHANGELOG.md

@@ -246,28 +246,38 @@ List<String> calculateOrderedStages(
     );
   }
 
-  // Running strongly connected components lets us detect cycles (which aren't
-  // allowed), and gives us the reverse order of what we ultimately want.
-  final components = stronglyConnectedComponents(edges.keys, (n) => edges[n]!);
-  for (var component in components) {
-    if (component.length > 1) {
-      final items = component.map((e) => '`$e`').join(', ');
-      throw UserException(
-        'Not all packages agree on `stages` ordering, found '
-        'a cycle between the following stages: $items.',
-      );
-    }
+  final List<String> components;
+  try {
+    // Build up a map of the keys to their index in `edges.keys`, which we use
+    // as a secondary sort. This is an intuitive secondary sort order as it
+    // follows the order given in configuration files.
+    final keys = edges.keys.toList();
+    final edgeIndexes = {
+      for (var i = 0; i < keys.length; i++) keys[i]: i,
+    };
+
+    // Orders by dependencies first, and detect cycles (which aren't allowed).
+    // Our edges here are actually reverse edges already, so a topological sort
+    // gives us the right thing.
+    components = topologicalSort(
+      keys,
+      (n) => edges[n]!,
+      secondarySort: (a, b) => edgeIndexes[b]!.compareTo(edgeIndexes[a]!),
+    );
+  } on CycleException<String> catch (e) {
+    final items = e.cycle.map((e) => '`$e`').join(', ');
+    throw UserException(
+      'Not all packages agree on `stages` ordering, found '
+      'a cycle between the following stages: $items.',
+    );
   }
 
-  final orderedStages =
-      components.map((c) => c.first).toList().reversed.toList();
-
   if (rootConfig.monoConfig.selfValidateStage != null &&
-      !orderedStages.contains(rootConfig.monoConfig.selfValidateStage)) {
-    orderedStages.insert(0, rootConfig.monoConfig.selfValidateStage!);
+      !components.contains(rootConfig.monoConfig.selfValidateStage)) {
+    components.insert(0, rootConfig.monoConfig.selfValidateStage!);
   }
 
-  return orderedStages;
+  return components;
 }
 
 List<Task> _travisTasks(Iterable<PackageConfig> configs) =>

mono_repo/lib/src/ci_shared.dart

@@ -2,7 +2,7 @@ name: mono_repo
 description: >-
   CLI tools to make it easier to manage a single source repository containing
   multiple Dart packages.
-version: 6.5.5
+version: 6.5.6
 repository: https://github.com/google/mono_repo.dart
 topics:
  - tool
@@ -15,7 +15,7 @@ dependencies:
   args: ^2.0.0
   checked_yaml: ^2.0.0
   collection: ^1.14.3
-  graphs: ^2.0.0
+  graphs: ^2.2.0
   io: ^1.0.0
   json_annotation: ^4.8.0
   meta: ^1.0.0