Add support for formatting file-based apps

src/Cli/Microsoft.DotNet.FileBasedPrograms/InternalAPI.Unshipped.txt

@@ -69,7 +69,7 @@ static Microsoft.DotNet.FileBasedPrograms.VirtualProjectBuilder.GetPropertyFromS
 static Microsoft.DotNet.FileBasedPrograms.VirtualProjectBuilder.GetTempSubdirectory(string? dotNetSubdirectory = null) -> string!
 static Microsoft.DotNet.FileBasedPrograms.VirtualProjectBuilder.GetTempSubpath(string! name, string? dotNetSubdirectory = null) -> string!
 static Microsoft.DotNet.FileBasedPrograms.VirtualProjectBuilder.GetVirtualProjectPath(string! entryPointFilePath) -> string!
-static Microsoft.DotNet.FileBasedPrograms.VirtualProjectBuilder.IsValidEntryPointPath(string! entryPointFilePath) -> bool
+static Microsoft.DotNet.FileBasedPrograms.VirtualProjectBuilder.IsValidEntryPointPath(string! entryPointFilePath, bool requireFileToExist = true) -> bool
 static Microsoft.DotNet.FileBasedPrograms.VirtualProjectBuilder.TryGetEntryPointFilePathFromVirtualProjectPath(string! projectPath, out string? entryPointFilePath) -> bool
 static Microsoft.DotNet.FileBasedPrograms.VirtualProjectBuilder.WriteProjectFile(System.IO.TextWriter! writer, System.Collections.Immutable.ImmutableArray<Microsoft.DotNet.FileBasedPrograms.CSharpDirective!> directives, System.Collections.Generic.IEnumerable<(string! name, string! value)>! defaultProperties, bool isVirtualProject, string? entryPointFilePath = null, string? artifactsPath = null, bool includeRuntimeConfigInformation = true, string? userSecretsId = null, System.Collections.Immutable.ImmutableArray<Microsoft.DotNet.FileBasedPrograms.VirtualProjectBuilder.ExplicitProjectItem> explicitProjectItems = default(System.Collections.Immutable.ImmutableArray<Microsoft.DotNet.FileBasedPrograms.VirtualProjectBuilder.ExplicitProjectItem>)) -> void
 static Microsoft.DotNet.Utilities.Extensions.ToHashSet<T>(this System.Collections.Generic.IEnumerable<T>! source, System.Collections.Generic.IEqualityComparer<T>! comparer) -> System.Collections.Generic.HashSet<T>!

src/Cli/Microsoft.DotNet.FileBasedPrograms/VirtualProjectBuilder.cs

@@ -171,9 +171,9 @@ internal static string GetTempSubpath(string name, string? dotNetSubdirectory =
         return Path.Combine(GetTempSubdirectory(dotNetSubdirectory), name);
     }
 
-    public static bool IsValidEntryPointPath(string entryPointFilePath)
+    public static bool IsValidEntryPointPath(string entryPointFilePath, bool requireFileToExist = true)
     {
-        if (!File.Exists(entryPointFilePath))
+        if (requireFileToExist && !File.Exists(entryPointFilePath))
         {
             return false;
         }
@@ -183,6 +183,12 @@ public static bool IsValidEntryPointPath(string entryPointFilePath)
             return true;
         }
 
+        // If we haven't checked file existence yet, do it before opening the file.
+        if (!requireFileToExist && !File.Exists(entryPointFilePath))
+        {
+            return false;
+        }
+
         // Check if the first two characters are #!
         try
         {

src/Dotnet.Format/dotnet-format/CodeFormatter.cs

@@ -35,15 +35,17 @@ public static async Task<WorkspaceFormatResult> FormatWorkspaceAsync(
 
             var workspaceStopwatch = Stopwatch.StartNew();
 
-            using var workspace = formatOptions.WorkspaceType == WorkspaceType.Folder
+            using var loadedWorkspace = formatOptions.WorkspaceType == WorkspaceType.Folder
                 ? OpenFolderWorkspace(formatOptions.WorkspaceFilePath, formatOptions.FileMatcher)
                 : await OpenMSBuildWorkspaceAsync(formatOptions.WorkspaceFilePath, formatOptions.WorkspaceType, formatOptions.NoRestore, formatOptions.FixCategory != FixCategory.Whitespace, formatOptions.BinaryLogPath, logWorkspaceWarnings, logger, formatOptions.TargetFramework, cancellationToken);
 
-            if (workspace is null)
+            if (loadedWorkspace is null)
             {
                 return new WorkspaceFormatResult(filesFormatted: 0, fileCount: 0, exitCode: 1);
             }
 
+            var workspace = loadedWorkspace.Workspace;
+
             if (formatOptions.LogLevel <= LogLevel.Debug)
             {
                 foreach (var project in workspace.CurrentSolution.Projects)
@@ -58,13 +60,12 @@ public static async Task<WorkspaceFormatResult> FormatWorkspaceAsync(
             var loadWorkspaceMS = workspaceStopwatch.ElapsedMilliseconds;
             logger.LogTrace(Resources.Complete_in_0_ms, loadWorkspaceMS);
 
-            var projectPath = formatOptions.WorkspaceType == WorkspaceType.Project ? formatOptions.WorkspaceFilePath : string.Empty;
             var solution = workspace.CurrentSolution;
 
             logger.LogTrace(Resources.Determining_formattable_files);
 
             var (fileCount, formatableFiles) = await DetermineFormattableFilesAsync(
-                solution, projectPath, formatOptions, logger, cancellationToken);
+                solution, loadedWorkspace.ProjectId, formatOptions, logger, cancellationToken);
 
             var determineFilesMS = workspaceStopwatch.ElapsedMilliseconds - loadWorkspaceMS;
             logger.LogTrace(Resources.Complete_in_0_ms, determineFilesMS);
@@ -110,14 +111,14 @@ public static async Task<WorkspaceFormatResult> FormatWorkspaceAsync(
             return new WorkspaceFormatResult(documentIdsWithErrors.Length, fileCount, exitCode);
         }
 
-        private static Workspace OpenFolderWorkspace(string workspacePath, SourceFileMatcher fileMatcher)
+        private static LoadedWorkspace OpenFolderWorkspace(string workspacePath, SourceFileMatcher fileMatcher)
         {
             var folderWorkspace = FolderWorkspace.Create();
             folderWorkspace.OpenFolder(workspacePath, fileMatcher);
-            return folderWorkspace;
+            return new LoadedWorkspace(folderWorkspace, ProjectId: null);
         }
 
-        private static async Task<Workspace?> OpenMSBuildWorkspaceAsync(
+        private static async Task<LoadedWorkspace?> OpenMSBuildWorkspaceAsync(
             string solutionOrProjectPath,
             WorkspaceType workspaceType,
             bool noRestore,
@@ -165,11 +166,13 @@ private static async Task<Solution> RunCodeFormattersAsync(
 
         internal static async Task<(int, ImmutableArray<DocumentId>)> DetermineFormattableFilesAsync(
             Solution solution,
-            string projectPath,
+            ProjectId? projectId,
             FormatOptions formatOptions,
             ILogger logger,
             CancellationToken cancellationToken)
         {
+            Debug.Assert((formatOptions.WorkspaceType is WorkspaceType.Project) == (projectId is not null));
+
             var totalFileCount = solution.Projects.Sum(project => project.DocumentIds.Count);
             var projectFileCount = 0;
 
@@ -187,7 +190,7 @@ private static async Task<Solution> RunCodeFormattersAsync(
                 }
 
                 // If a project is used as a workspace, then ignore other referenced projects.
-                if (!string.IsNullOrEmpty(projectPath) && !project.FilePath.Equals(projectPath, StringComparison.OrdinalIgnoreCase))
+                if (projectId != null && project.Id != projectId)
                 {
                     logger.LogDebug(Resources.Skipping_referenced_project_0, project.Name);
                     continue;

src/Dotnet.Format/dotnet-format/Commands/FormatCommandCommon.cs

@@ -20,9 +20,9 @@ internal static class FormatCommandCommon
         private static string[] VerbosityLevels => new[] { "q", "quiet", "m", "minimal", "n", "normal", "d", "detailed", "diag", "diagnostic" };
         private static string[] SeverityLevels => new[] { "info", "warn", "error", "hidden" };
 
-        public static readonly Argument<string> SlnOrProjectArgument = new Argument<string>(Resources.SolutionOrProjectArgumentName)
+        public static readonly Argument<string> SlnOrProjectArgument = new Argument<string>(Resources.SolutionOrProjectOrFileArgumentName)
         {
-            Description = Resources.SolutionOrProjectArgumentDescription,
+            Description = Resources.SolutionOrProjectOrFileArgumentDescription,
             Arity = ArgumentArity.ZeroOrOne
         }.DefaultToCurrentDirectory();
 

src/Dotnet.Format/dotnet-format/Resources.resx

@@ -132,8 +132,8 @@
   <data name="Failed_to_save_formatting_changes" xml:space="preserve">
     <value>Failed to save formatting changes.</value>
   </data>
-  <data name="The_file_0_does_not_appear_to_be_a_valid_project_or_solution_file" xml:space="preserve">
-    <value>The file '{0}' does not appear to be a valid project or solution file.</value>
+  <data name="The_file_0_does_not_appear_to_be_a_valid_project_solution_file_or_file_based_app" xml:space="preserve">
+    <value>The file '{0}' does not appear to be a valid project, solution file, or file-based app.</value>
   </data>
   <data name="Multiple_MSBuild_project_files_found_in_0_Specify_which_to_use_with_the_workspace_argument" xml:space="preserve">
     <value>Multiple MSBuild project files found in '{0}'. Specify which to use with the &lt;workspace&gt; argument.</value>
@@ -336,11 +336,11 @@
   <data name="Cannot_specify_the_folder_option_with_framework" xml:space="preserve">
     <value>Cannot specify the '--folder' option with '--framework'.</value>
   </data>
-  <data name="SolutionOrProjectArgumentName" xml:space="preserve">
-    <value>PROJECT | SOLUTION</value>
+  <data name="SolutionOrProjectOrFileArgumentName" xml:space="preserve">
+    <value>PROJECT | SOLUTION | FILE</value>
   </data>
-  <data name="SolutionOrProjectArgumentDescription" xml:space="preserve">
-    <value>The project or solution file to operate on. If a file is not specified, the command will search the current directory for one.</value>
+  <data name="SolutionOrProjectOrFileArgumentDescription" xml:space="preserve">
+    <value>The project or solution or C# (file-based program) file to operate on. If a file is not specified, the command will search the current directory for a project or solution.</value>
   </data>
   <data name="Accepts_a_file_path_which_if_provided_will_produce_a_json_report_in_the_given_directory" xml:space="preserve">
     <value>Accepts a file path which if provided will produce a json report in the given directory.</value>

src/Dotnet.Format/dotnet-format/Workspaces/MSBuildWorkspaceFinder.cs

@@ -6,6 +6,8 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 // See https://github.com/aspnet/DotNetTools/blob/261b27b70027871143540af10a5cba57ce07ff97/src/dotnet-watch/Internal/MsBuildProjectFinder.cs
 
+using Microsoft.DotNet.FileBasedPrograms;
+
 namespace Microsoft.CodeAnalysis.Tools.Workspaces
 {
     internal class MSBuildWorkspaceFinder
@@ -62,10 +64,12 @@ private static (bool isSolution, string workspacePath) FindFile(string workspace
             var isProject = !isSolution
                 && workspaceExtension.EndsWith("proj", StringComparison.OrdinalIgnoreCase)
                 && !workspaceExtension.Equals(DnxProjectExtension, StringComparison.OrdinalIgnoreCase);
+            var isFileBasedApp = !isSolution && !isProject
+                && VirtualProjectBuilder.IsValidEntryPointPath(workspacePath, requireFileToExist: false);
 
-            if (!isSolution && !isProject)
+            if (!isSolution && !isProject && !isFileBasedApp)
             {
-                throw new FileNotFoundException(string.Format(Resources.The_file_0_does_not_appear_to_be_a_valid_project_or_solution_file, Path.GetFileName(workspacePath)));
+                throw new FileNotFoundException(string.Format(Resources.The_file_0_does_not_appear_to_be_a_valid_project_solution_file_or_file_based_app, Path.GetFileName(workspacePath)));
             }
 
             if (!File.Exists(workspacePath))

src/Dotnet.Format/dotnet-format/Workspaces/MSBuildWorkspaceLoader.cs

@@ -12,7 +12,7 @@ internal static class MSBuildWorkspaceLoader
         // Used in tests for locking around MSBuild invocations
         internal static readonly SemaphoreSlim Guard = new SemaphoreSlim(1, 1);
 
-        public static async Task<Workspace?> LoadAsync(
+        public static async Task<LoadedWorkspace?> LoadAsync(
             string solutionOrProjectPath,
             WorkspaceType workspaceType,
             string? binaryLogPath,
@@ -35,6 +35,7 @@ internal static class MSBuildWorkspaceLoader
             }
 
             var workspace = MSBuildWorkspace.Create(properties);
+            ProjectId? projectId = null;
 
             Build.Framework.ILogger? binlog = null;
             if (binaryLogPath is not null)
@@ -54,7 +55,8 @@ internal static class MSBuildWorkspaceLoader
             {
                 try
                 {
-                    await workspace.OpenProjectAsync(solutionOrProjectPath, msbuildLogger: binlog, cancellationToken: cancellationToken);
+                    var project = await workspace.OpenProjectAsync(solutionOrProjectPath, msbuildLogger: binlog, cancellationToken: cancellationToken);
+                    projectId = project.Id;
                 }
                 catch (InvalidOperationException)
                 {
@@ -66,7 +68,7 @@ internal static class MSBuildWorkspaceLoader
 
             LogWorkspaceDiagnostics(logger, logWorkspaceWarnings, workspace.Diagnostics);
 
-            return workspace;
+            return new LoadedWorkspace(workspace, projectId);
 
             static void LogWorkspaceDiagnostics(ILogger logger, bool logWorkspaceWarnings, ImmutableList<WorkspaceDiagnostic> diagnostics)
             {
@@ -94,4 +96,10 @@ static void LogWorkspaceDiagnostics(ILogger logger, bool logWorkspaceWarnings, I
             }
         }
     }
+
+    /// <param name="ProjectId">Set to the project if the workspace is loaded in "project" mode.</param>
+    internal sealed record LoadedWorkspace(Workspace Workspace, ProjectId? ProjectId) : IDisposable
+    {
+        public void Dispose() => Workspace.Dispose();
+    }
 }

src/Dotnet.Format/dotnet-format/dotnet-format.csproj

@@ -40,6 +40,10 @@
     <PackageReference Include="System.CommandLine" />
   </ItemGroup>
 
+  <ItemGroup>
+    <ProjectReference Include="..\..\Microsoft.DotNet.ProjectTools\Microsoft.DotNet.ProjectTools.csproj" />
+  </ItemGroup>
+
   <ItemGroup>
     <InternalsVisibleTo Include="dotnet-format.UnitTests" />
     <InternalsVisibleTo Include="dotnet-format.PerformanceTests" />