Improve parent branch selection

Author: geofflamrock

src/Stack/Commands/Branch/NewBranchCommand.cs

@@ -68,16 +68,28 @@ public override async Task Handle(NewBranchCommandInputs inputs)
             return;
         }
 
+        if (stackData.SchemaVersion == SchemaVersion.V1 && inputs.ParentBranchName is not null)
+        {
+            throw new InvalidOperationException("Parent branches are not supported in stacks with schema version v1. Please migrate the stack to v2 format.");
+        }
+
         var stack = inputProvider.SelectStack(logger, inputs.StackName, stacksForRemote, currentBranch);
 
         if (stack is null)
         {
             throw new InvalidOperationException($"Stack '{inputs.StackName}' not found.");
         }
 
-        if (stackData.SchemaVersion == SchemaVersion.V1 && inputs.ParentBranchName is not null)
+        var branchName = inputProvider.Text(logger, Questions.BranchName, inputs.BranchName, stack.GetDefaultBranchName());
+
+        if (stack.AllBranchNames.Contains(branchName))
         {
-            throw new InvalidOperationException("Parent branches are not supported in stacks with schema version v1. Please migrate the stack to v2 format.");
+            throw new InvalidOperationException($"Branch '{branchName}' already exists in stack '{stack.Name}'.");
+        }
+
+        if (gitClient.DoesLocalBranchExist(branchName))
+        {
+            throw new InvalidOperationException($"Branch '{branchName}' already exists locally.");
         }
 
         Branch? sourceBranch = null;
@@ -89,28 +101,18 @@ public override async Task Handle(NewBranchCommandInputs inputs)
         }
         if (stackData.SchemaVersion == SchemaVersion.V2)
         {
-            var parentBranchName = inputs.ParentBranchName ?? inputProvider.SelectBranch(logger, null, [stack.SourceBranch, .. stack.AllBranchNames], Questions.SelectParentBranch);
+            var parentBranchName = inputProvider.SelectParentBranch(logger, inputs.ParentBranchName, stack);
 
-            var flattenedBranches = stack.Branches.SelectMany(branch => MoreEnumerable.TraverseDepthFirst(branch, b => b.Children)).ToList();
-            sourceBranch = flattenedBranches.FirstOrDefault(b => b.Name.Equals(parentBranchName, StringComparison.OrdinalIgnoreCase));
-            if (sourceBranch is null)
+            if (parentBranchName != stack.SourceBranch)
             {
-                throw new InvalidOperationException($"Branch '{parentBranchName}' not found in stack '{stack.Name}'.");
+                sourceBranch = stack.GetAllBranches().FirstOrDefault(b => b.Name.Equals(parentBranchName, StringComparison.OrdinalIgnoreCase));
+                if (sourceBranch is null)
+                {
+                    throw new InvalidOperationException($"Branch '{parentBranchName}' not found in stack '{stack.Name}'.");
+                }
             }
         }
 
-        var branchName = inputProvider.Text(logger, Questions.BranchName, inputs.BranchName, stack.GetDefaultBranchName());
-
-        if (stack.AllBranchNames.Contains(branchName))
-        {
-            throw new InvalidOperationException($"Branch '{branchName}' already exists in stack '{stack.Name}'.");
-        }
-
-        if (gitClient.DoesLocalBranchExist(branchName))
-        {
-            throw new InvalidOperationException($"Branch '{branchName}' already exists locally.");
-        }
-
         var sourceBranchName = sourceBranch?.Name ?? stack.SourceBranch;
 
         logger.Information($"Creating branch {branchName.Branch()} from {sourceBranchName.Branch()} in stack {stack.Name.Stack()}");

src/Stack/Commands/Helpers/InputProviderExtensionMethods.cs

@@ -84,5 +84,33 @@ public static string SelectBranch(
     {
         return inputProvider.Select(logger, question, name, branches);
     }
+
+    public static string SelectParentBranch(
+        this IInputProvider inputProvider,
+        ILogger logger,
+        string? name,
+        Config.Stack stack)
+    {
+        void GetBranchNamesWithIndentation(Branch branch, List<string> names, int level = 0)
+        {
+            names.Add($"{new string(' ', level * 2)}{branch.Name}");
+            foreach (var child in branch.Children)
+            {
+                GetBranchNamesWithIndentation(child, names, level + 1);
+            }
+        }
+
+        var allBranchNamesWithLevel = new List<string>();
+        foreach (var branch in stack.Branches)
+        {
+            GetBranchNamesWithIndentation(branch, allBranchNamesWithLevel, 1);
+        }
+
+        var branchSelection = name ?? inputProvider.Select(Questions.SelectParentBranch, [stack.SourceBranch, .. allBranchNamesWithLevel]).Trim();
+
+        logger.Information($"{Questions.SelectParentBranch} {branchSelection}");
+
+        return branchSelection;
+    }
 }
 

src/Stack/Config/Stack.cs

@@ -36,18 +36,7 @@ static List<Branch> GetAllBranches(Branch branch)
         return branchesToReturn;
     }
 
-    public List<string> AllBranchNames
-    {
-        get
-        {
-            var branches = new List<string>();
-            foreach (var branch in Branches)
-            {
-                branches.AddRange(branch.AllBranchNames);
-            }
-            return [.. branches.Distinct()];
-        }
-    }
+    public List<string> AllBranchNames => [.. GetAllBranches().Select(b => b.Name).Distinct()];
 
     public bool HasSingleTree
     {