Allow 'Add project reference' for existing projects

src/Assets/TestPackages/dotnet-new/test_templates/PostActions/AddProjectReference/Existing/.template.config/template.json

@@ -0,0 +1,34 @@
+{
+  "author": "Test Asset",
+  "classifications": [ "Test Asset" ],
+  "name": "TestAssets.PostActions.AddProjectReference.Existing",
+  "groupIdentity": "TestAssets.PostActions.AddProjectReference.Existing",
+  "precedence": "100",
+  "identity": "TestAssets.PostActions.AddProjectReference.Existing",
+  "shortName": "TestAssets.PostActions.AddProjectReference.Existing",
+  "primaryOutputs": [
+    {
+      "path": "Project1/Project1.csproj"
+    }
+  ],
+  "postActions": [
+    {
+      "Description": "Add ProjectReference to ExistingProject/ExistingProject.csproj",
+      "ActionId": "B17581D1-C5C9-4489-8F0A-004BE667B814",
+      "ContinueOnError": "false",
+      "ManualInstructions": [
+        {
+          "Text": "Manually add the reference to Project1 in ExistingProject"
+        }
+      ],
+      "args": {
+        "targetFiles": [
+          "ExistingProject/ExistingProject.csproj"
+        ],
+        "referenceType": "project",
+        "reference": "Project1/Project1.csproj",
+        "projectFileExtensions": ".csproj"
+      }
+    }
+  ]
+}

src/Assets/TestPackages/dotnet-new/test_templates/PostActions/AddProjectReference/Existing/Project1/Program.cs

@@ -0,0 +1,12 @@
+using System;
+
+namespace Project1
+{
+    public class Program
+    {
+        public static void Main(string[] args)
+        {
+            Console.WriteLine("Hello World!");
+        }
+    }
+}

src/Assets/TestPackages/dotnet-new/test_templates/PostActions/AddProjectReference/Existing/Project1/Project1.csproj

@@ -0,0 +1,8 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>$(CurrentTargetFramework)</TargetFramework>
+  </PropertyGroup>
+
+</Project>

src/Assets/TestPackages/dotnet-new/test_templates/PostActions/AddProjectReference/ExistingWithRename/.template.config/template.json

@@ -0,0 +1,46 @@
+{
+  "author": "Test Asset",
+  "classifications": [ "Test Asset" ],
+  "name": "TestAssets.PostActions.AddProjectReference.ExistingWithRename",
+  "groupIdentity": "TestAssets.PostActions.AddProjectReference.ExistingWithRename",
+  "precedence": "100",
+  "identity": "TestAssets.PostActions.AddProjectReference.ExistingWithRename",
+  "shortName": "TestAssets.PostActions.AddProjectReference.ExistingWithRename",
+  "primaryOutputs": [
+    {
+      "path": "Project1/Project1.csproj"
+    }
+  ],
+  "symbols": {
+    "existingProject": {
+      "displayName": "Existing project relative path",
+      "description": "Path relative to the working directory",
+      "type": "parameter",
+      "datatype": "string",
+      "defaultValue": "ExistingProject/ExistingProject.csproj",
+      "fileRename": "ExistingProjectPath"
+    }
+  },
+  "postActions": [
+    {
+      "Description": "Add ProjectReference to ExistingProject/ExistingProject.csproj",
+      "ActionId": "B17581D1-C5C9-4489-8F0A-004BE667B814",
+      "ContinueOnError": "false",
+      "ManualInstructions": [
+        {
+          "Text": "Manually add the reference to Project1 in ExistingProject"
+        }
+      ],
+      "applyFileRenamesToArgs": [
+        "targetFiles"
+      ],
+      "args": {
+        "targetFiles": [
+          "ExistingProjectPath"
+        ],
+        "referenceType": "project",
+        "reference": "Project1/Project1.csproj"
+      }
+    }
+  ]
+}

src/Assets/TestPackages/dotnet-new/test_templates/PostActions/AddProjectReference/ExistingWithRename/Project1/Program.cs

@@ -0,0 +1,12 @@
+using System;
+
+namespace Project1
+{
+    public class Program
+    {
+        public static void Main(string[] args)
+        {
+            Console.WriteLine("Hello World!");
+        }
+    }
+}

src/Assets/TestPackages/dotnet-new/test_templates/PostActions/AddProjectReference/ExistingWithRename/Project1/Project1.csproj

@@ -0,0 +1,8 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <OutputType>Exe</OutputType>
+    <TargetFramework>$(CurrentTargetFramework)</TargetFramework>
+  </PropertyGroup>
+
+</Project>

src/Cli/Microsoft.TemplateEngine.Cli/PostActionProcessors/PostActionProcessorBase.cs

@@ -47,7 +47,7 @@ protected static IReadOnlyList<string> GetTargetForSource(ICreationEffects2 crea
             return results;
         }
 
-        protected static IReadOnlyList<string>? GetConfiguredFiles(
+        protected static IReadOnlyList<string> GetConfiguredFiles(
             IReadOnlyDictionary<string, string> postActionArgs,
             ICreationEffects creationEffects,
             string argName,
@@ -56,47 +56,20 @@ protected static IReadOnlyList<string> GetTargetForSource(ICreationEffects2 crea
         {
             if (creationEffects is not ICreationEffects2 creationEffects2)
             {
-                return null;
+                return new List<string>();
             }
             if (!postActionArgs.TryGetValue(argName, out string? targetFiles))
             {
-                return null;
+                return new List<string>();
             }
             if (string.IsNullOrWhiteSpace(targetFiles))
             {
-                return null;
+                return new List<string>();
             }
 
-            // try to parse the argument as json; if it is not valid json, use it as a string
-            if (targetFiles.TryParse(out JToken? config))
+            if (TryParseAsJson(targetFiles, out IReadOnlyList<string> paths))
             {
-                if (config == null)
-                {
-                    return null;
-                }
-
-                if (config.Type == JTokenType.String)
-                {
-                    return ProcessPaths(config.ToString().Split(new[] { ';' }, StringSplitOptions.RemoveEmptyEntries));
-                }
-                else if (config is JArray arr)
-                {
-                    List<string> parts = new();
-
-                    foreach (JToken token in arr)
-                    {
-                        if (token.Type != JTokenType.String)
-                        {
-                            continue;
-                        }
-                        parts.Add(token.ToString());
-                    }
-
-                    if (parts.Count > 0)
-                    {
-                        return ProcessPaths(parts);
-                    }
-                }
+                return ProcessPaths(paths);
             }
 
             return ProcessPaths(targetFiles.Split(new[] { ';' }, StringSplitOptions.RemoveEmptyEntries));
@@ -111,11 +84,72 @@ IReadOnlyList<string> ProcessPaths(IReadOnlyList<string> paths)
             }
         }
 
+        protected static IReadOnlyList<string>? GetTargetFilesPaths(
+            IReadOnlyDictionary<string, string> postActionArgs,
+            string outputBasePath)
+        {
+            postActionArgs.TryGetValue("targetFiles", out string? targetFiles);
+            if (string.IsNullOrWhiteSpace(targetFiles))
+            {
+                return null;
+            }
+
+            // try to parse the argument as json; if it is not valid json, use it as a string
+            if (TryParseAsJson(targetFiles, out IReadOnlyList<string> paths))
+            {
+                return GetFullPaths(paths);
+            }
+
+            return GetFullPaths(targetFiles.Split(new[] { ';' }, StringSplitOptions.RemoveEmptyEntries));
+
+            IReadOnlyList<string> GetFullPaths(IEnumerable<string> paths)
+            {
+                var fullPaths = paths
+                    .Select(p => Path.GetFullPath(p, outputBasePath))
+                    .ToList();
+
+                return fullPaths.AsReadOnly();
+            }
+        }
+
         protected abstract bool ProcessInternal(
             IEngineEnvironmentSettings environment,
             IPostAction action,
             ICreationEffects creationEffects,
             ICreationResult templateCreationResult,
             string outputBasePath);
+
+        private static bool TryParseAsJson(string targetFiles, out IReadOnlyList<string> paths)
+        {
+            paths = new List<string>();
+            targetFiles.TryParse(out JToken? config);
+            if (config is null)
+            {
+                return false;
+            }
+
+            if (config.Type == JTokenType.String)
+            {
+                paths = config.ToString().Split(new[] { ';' }, StringSplitOptions.RemoveEmptyEntries);
+                return true;
+            }
+
+            if (config is not JArray arr)
+            {
+                return false;
+            }
+
+            var parts = arr
+                .Where(token => token.Type == JTokenType.String)
+                .Select(token => token.ToString()).ToList();
+
+            if (parts.Count == 0)
+            {
+                return false;
+            }
+
+            paths = parts.AsReadOnly();
+            return true;
+        }
     }
 }

src/Cli/dotnet/commands/dotnet-new/PostActions/DotnetAddPostActionProcessor.cs

@@ -44,7 +44,7 @@ protected override bool ProcessInternal(IEngineEnvironmentSettings environment,
         {
             IReadOnlyList<string>? projectsToProcess = GetConfiguredFiles(action.Args, creationEffects, "targetFiles", outputBasePath);
 
-            if (projectsToProcess is null)
+            if (!projectsToProcess.Any())
             {
                 //If the author didn't opt in to the new behavior by specifying "targetFiles", search for project file in current output directory or above.
                 HashSet<string> extensionLimiters = new(StringComparer.Ordinal);
@@ -59,7 +59,7 @@ protected override bool ProcessInternal(IEngineEnvironmentSettings environment,
 
                     extensionLimiters.UnionWith(projectFileExtensions.Split(new[] { ';' }, StringSplitOptions.RemoveEmptyEntries));
                 }
-                projectsToProcess = FindProjFileAtOrAbovePath(environment.Host.FileSystem, outputBasePath, extensionLimiters);
+                projectsToProcess = TryFindProjects(environment, outputBasePath, extensionLimiters);
                 if (projectsToProcess.Count > 1)
                 {
                     // multiple projects at the same level. Error.
@@ -72,7 +72,13 @@ protected override bool ProcessInternal(IEngineEnvironmentSettings environment,
                     return false;
                 }
             }
-            if (projectsToProcess is null || !projectsToProcess.Any())
+
+            if (!projectsToProcess.Any())
+            {
+                projectsToProcess = FindExistingTargetFiles(environment.Host.FileSystem, action.Args, outputBasePath);
+            }
+
+            if (!projectsToProcess.Any())
             {
                 // no projects found. Error.
                 Reporter.Error.WriteLine(LocalizableStrings.PostAction_AddReference_Error_UnresolvedProjFile);
@@ -92,6 +98,27 @@ protected override bool ProcessInternal(IEngineEnvironmentSettings environment,
             return true;
         }
 
+        private static IReadOnlyList<string> TryFindProjects(IEngineEnvironmentSettings environment, string outputBasePath, HashSet<string> extensionLimiters)
+        {
+            try
+            {
+                return FindProjFileAtOrAbovePath(environment.Host.FileSystem, outputBasePath, extensionLimiters);
+            }
+            catch (DirectoryNotFoundException)
+            {
+                return [];
+            }
+        }
+
+        private static IReadOnlyList<string> FindExistingTargetFiles(IPhysicalFileSystem fileSystem, IReadOnlyDictionary<string, string> actionArgs, string outputBasePath)
+        {
+            var targetFiles = GetTargetFilesPaths(actionArgs, outputBasePath);
+            var foundFiles = targetFiles?
+                .Where(fileSystem.FileExists)
+                .ToList();
+            return foundFiles ?? [];
+        }
+
         private bool AddReference(IPostAction actionConfig, string projectFile, string outputBasePath, ICreationEffects creationEffects)
         {
             if (actionConfig.Args == null || !actionConfig.Args.TryGetValue("reference", out string? referenceToAdd))

src/Cli/dotnet/commands/dotnet-new/PostActions/DotnetRestorePostActionProcessor.cs

@@ -25,9 +25,9 @@ public DotnetRestorePostActionProcessor(Func<string, bool>? restoreCallback = nu
         protected override bool ProcessInternal(IEngineEnvironmentSettings environment, IPostAction actionConfig, ICreationEffects creationEffects, ICreationResult templateCreationResult, string outputBasePath)
         {
             bool allSucceeded = true;
-            IEnumerable<string>? targetFiles = GetConfiguredFiles(actionConfig.Args, creationEffects, "files", outputBasePath);
+            IEnumerable<string> targetFiles = GetConfiguredFiles(actionConfig.Args, creationEffects, "files", outputBasePath);
 
-            if (targetFiles is null || !targetFiles.Any())
+            if (!targetFiles.Any())
             {
                 //If the author didn't opt in to the new behavior by specifying "projectFiles", use the old behavior - primary outputs
                 if (templateCreationResult.PrimaryOutputs.Count == 0)
@@ -38,7 +38,7 @@ protected override bool ProcessInternal(IEngineEnvironmentSettings environment,
                 targetFiles = templateCreationResult.PrimaryOutputs.Select(output => Path.GetFullPath(output.Path, outputBasePath));
             }
 
-            if (targetFiles is null || !targetFiles.Any())
+            if (!targetFiles.Any())
             {
                 Reporter.Error.WriteLine(string.Format(LocalizableStrings.PostAction_Restore_Error_FailedToDetermineProjectToRestore));
                 return false;

src/Cli/dotnet/commands/dotnet-new/PostActions/DotnetSlnPostActionProcessor.cs

@@ -32,9 +32,10 @@ internal static IReadOnlyList<string> FindSolutionFilesAtOrAbovePath(IPhysicalFi
 
         // The project files to add are a subset of the primary outputs, specifically the primary outputs indicated by the primaryOutputIndexes post action argument (semicolon separated)
         // If any indexes are out of range or non-numeric, this method returns false and projectFiles is set to null.
-        internal static bool TryGetProjectFilesToAdd(IPostAction actionConfig, ICreationResult templateCreationResult, string outputBasePath, [NotNullWhen(true)] out IReadOnlyList<string>? projectFiles)
+        internal static bool TryGetProjectFilesToAdd(IPostAction actionConfig, ICreationResult templateCreationResult, string outputBasePath, [NotNullWhen(true)] out IReadOnlyList<string> projectFiles)
         {
             List<string> filesToAdd = new();
+            projectFiles = new List<string>();
 
             if ((actionConfig.Args != null) && actionConfig.Args.TryGetValue("primaryOutputIndexes", out string? projectIndexes))
             {
@@ -44,15 +45,13 @@ internal static bool TryGetProjectFilesToAdd(IPostAction actionConfig, ICreation
                     {
                         if (templateCreationResult.PrimaryOutputs.Count <= index || index < 0)
                         {
-                            projectFiles = null;
                             return false;
                         }
 
                         filesToAdd.Add(Path.GetFullPath(templateCreationResult.PrimaryOutputs[index].Path, outputBasePath));
                     }
                     else
                     {
-                        projectFiles = null;
                         return false;
                     }
                 }
@@ -81,8 +80,8 @@ protected override bool ProcessInternal(IEngineEnvironmentSettings environment,
                 return false;
             }
 
-            IReadOnlyList<string>? projectFiles = GetConfiguredFiles(action.Args, creationEffects, "projectFiles", outputBasePath, (path) => Path.GetExtension(path).EndsWith("proj", StringComparison.OrdinalIgnoreCase));
-            if (projectFiles is null)
+            IReadOnlyList<string> projectFiles = GetConfiguredFiles(action.Args, creationEffects, "projectFiles", outputBasePath, (path) => Path.GetExtension(path).EndsWith("proj", StringComparison.OrdinalIgnoreCase));
+            if (!projectFiles.Any())
             {
                 //If the author didn't opt in to the new behavior by specifying "projectFiles", use the old behavior
                 if (!TryGetProjectFilesToAdd(action, templateCreationResult, outputBasePath, out projectFiles))

test/dotnet-new.Tests/Approvals/DotnetNewDetailsTest.CanDisplayDetails_InstalledPackage_LocalPackage.Linux.verified.txt

@@ -25,6 +25,8 @@
       TestAssets.PostActions.AddPackageReference.B...  TestAssets.PostActions.AddPackageReference.Basic                                          Test Asset          
       TestAssets.PostActions.AddPackageReference.B...  TestAssets.PostActions.AddPackageReference.BasicWithFiles                                 Test Asset          
       TestAssets.PostActions.AddProjectReference.B...  TestAssets.PostActions.AddProjectReference.Basic                                          Test Asset          
+      TestAssets.PostActions.AddProjectReference.E...  TestAssets.PostActions.AddProjectReference.Existing                                       Test Asset          
+      TestAssets.PostActions.AddProjectReference.E...  TestAssets.PostActions.AddProjectReference.ExistingWithRename                             Test Asset          
       TestAssets.PostActions.AddProjectToSolution....  TestAssets.PostActions.AddProjectToSolution.Basic                                         Test Asset          
       TestAssets.PostActions.AddProjectToSolution....  TestAssets.PostActions.AddProjectToSolution.BasicInSolutionRoot                           Test Asset          
       TestAssets.PostActions.AddProjectToSolution....  TestAssets.PostActions.AddProjectToSolution.BasicWithFiles                                Test Asset          

test/dotnet-new.Tests/Approvals/DotnetNewDetailsTest.CanDisplayDetails_InstalledPackage_LocalPackage.OSX.verified.txt

@@ -25,6 +25,8 @@
       TestAssets.PostActions.AddPackageReference.B...  TestAssets.PostActions.AddPackageReference.Basic                                          Test Asset          
       TestAssets.PostActions.AddPackageReference.B...  TestAssets.PostActions.AddPackageReference.BasicWithFiles                                 Test Asset          
       TestAssets.PostActions.AddProjectReference.B...  TestAssets.PostActions.AddProjectReference.Basic                                          Test Asset          
+      TestAssets.PostActions.AddProjectReference.E...  TestAssets.PostActions.AddProjectReference.Existing                                       Test Asset          
+      TestAssets.PostActions.AddProjectReference.E...  TestAssets.PostActions.AddProjectReference.ExistingWithRename                             Test Asset          
       TestAssets.PostActions.AddProjectToSolution....  TestAssets.PostActions.AddProjectToSolution.Basic                                         Test Asset          
       TestAssets.PostActions.AddProjectToSolution....  TestAssets.PostActions.AddProjectToSolution.BasicInSolutionRoot                           Test Asset          
       TestAssets.PostActions.AddProjectToSolution....  TestAssets.PostActions.AddProjectToSolution.BasicWithFiles                                Test Asset