refactor(merge)!: add MergeAnalysis class containing analysis result and merge preference

BREAKING CHANGE: Return value of Merge.analysis(...) changed from List<Object> to MergeAnalysis.

lib/src/merge.dart

@@ -46,11 +46,10 @@ class Merge {
   /// opportunities for merging them into [ourRef] reference (default is
   /// 'HEAD').
   ///
-  /// Returns list with analysis result and preference for fast forward merge
+  /// Returns analysis result and preference for fast forward merge.
-  /// values respectively.
   ///
   /// Throws a [LibGit2Error] if error occured.
-  static List<Object> analysis({
+  static MergeAnalysis analysis({
     required Repository repo,
     required Oid theirHead,
     String ourRef = 'HEAD',
@@ -67,14 +66,14 @@ class Merge {
       theirHeadsLen: 1,
     );
 
-    final analysisSet = GitMergeAnalysis.values
+    final result = GitMergeAnalysis.values
         .where((e) => analysisInt[0] & e.value == e.value)
         .toSet();
-    final mergePreference = GitMergePreference.values.singleWhere(
+    final preference = GitMergePreference.values.singleWhere(
       (e) => analysisInt[1] == e.value,
     );
 
-    return <Object>[analysisSet, mergePreference];
+    return MergeAnalysis._(result: result, mergePreference: preference);
   }
 
   /// Merges the given [commit] into HEAD, writing the results into the
@@ -296,3 +295,13 @@ class Merge {
     );
   }
 }
+
+class MergeAnalysis {
+  const MergeAnalysis._({required this.result, required this.mergePreference});
+
+  /// Merge opportunities.
+  final Set<GitMergeAnalysis> result;
+
+  /// The user's stated preference for merges.
+  final GitMergePreference mergePreference;
+}

test/merge_test.dart

@@ -26,23 +26,19 @@ void main() {
   group('Merge', () {
     group('analysis', () {
       test('is up to date when no reference is provided', () {
-        expect(
+        final analysis = Merge.analysis(repo: repo, theirHead: repo['c68ff54']);
-          Merge.analysis(repo: repo, theirHead: repo['c68ff54']),
+        expect(analysis.result, {GitMergeAnalysis.upToDate});
-          [
+        expect(analysis.mergePreference, GitMergePreference.none);
-            {GitMergeAnalysis.upToDate},
-            GitMergePreference.none,
-          ],
-        );
         expect(repo.status, isEmpty);
       });
 
       test('is up to date for provided ref', () {
-        final result = Merge.analysis(
+        final analysis = Merge.analysis(
           repo: repo,
           theirHead: repo['c68ff54'],
           ourRef: 'refs/tags/v0.1',
         );
-        expect(result[0], {GitMergeAnalysis.upToDate});
+        expect(analysis.result, {GitMergeAnalysis.upToDate});
         expect(repo.status, isEmpty);
       });
 
@@ -53,21 +49,21 @@ void main() {
           target: Commit.lookup(repo: repo, oid: repo['f17d0d4']),
         );
 
-        final result = Merge.analysis(
+        final analysis = Merge.analysis(
           repo: repo,
           theirHead: repo['6cbc22e'],
           ourRef: 'refs/heads/${ffBranch.name}',
         );
         expect(
-          result[0],
+          analysis.result,
           {GitMergeAnalysis.fastForward, GitMergeAnalysis.normal},
         );
         expect(repo.status, isEmpty);
       });
 
       test('is not fast forward and there is no conflicts', () {
-        final result = Merge.analysis(repo: repo, theirHead: repo['5aecfa0']);
+        final analysis = Merge.analysis(repo: repo, theirHead: repo['5aecfa0']);
-        expect(result[0], {GitMergeAnalysis.normal});
+        expect(analysis.result, {GitMergeAnalysis.normal});
         expect(repo.status, isEmpty);
       });
     });
@@ -76,11 +72,11 @@ void main() {
       final conflictBranch = Branch.lookup(repo: repo, name: 'conflict-branch');
       final index = repo.index;
 
-      final result = Merge.analysis(
+      final analysis = Merge.analysis(
         repo: repo,
         theirHead: conflictBranch.target,
       );
-      expect(result[0], {GitMergeAnalysis.normal});
+      expect(analysis.result, {GitMergeAnalysis.normal});
 
       Merge.commit(
         repo: repo,