Fixed the file filters of the native file dialog for nested file types (#1079)

app/MindWork AI Studio/Tools/Rust/FileDialogFilter.cs

@@ -0,0 +1,13 @@
+namespace AIStudio.Tools.Rust;
+
+/// <summary>
+/// The file type filter of a native file dialog, as the runtime takes it.
+/// </summary>
+/// <remarks>
+/// This mirrors the struct FileTypeFilter in runtime/src/file_actions.rs, which knows one name and
+/// one flat list of extensions. A tree of file types never reaches the runtime: FileTypes.ToFileDialogFilter
+/// flattens it first, because the runtime would drop the children.
+/// </remarks>
+/// <param name="FilterName">The name of the filter, as some file dialogs show it.</param>
+/// <param name="FilterExtensions">The file extensions to show, without dot.</param>
+public sealed record FileDialogFilter(string FilterName, string[] FilterExtensions);

app/MindWork AI Studio/Tools/Rust/FileType.cs

@@ -1,41 +0,0 @@
-namespace AIStudio.Tools.Rust;
-
-/// <summary>
-/// Represents a file type that can optionally contain child file types.
-/// Use the static helpers <see cref="Leaf"/>,  <see cref="Parent"/> and <see cref="Composite"/> to build readable trees.
-/// </summary>
-/// <param name="FilterName">Display name of the type (e.g., "Document").</param>
-/// <param name="FilterExtensions">File extensions belonging to this type (without dot).</param>
-/// <param name="Children">Nested file types that are included when this type is selected.</param>
-public sealed record FileType(string FilterName, string[] FilterExtensions, IReadOnlyList<FileType> Children)
-{
-    /// <summary>
-    /// Factory for a leaf node.
-    /// Example: <c>FileType.Leaf(".NET", "cs", "razor")</c>
-    /// </summary>
-    public static FileType Leaf(string name, params string[] extensions) =>
-        new(name, extensions, []);
-
-    /// <summary>
-    /// Factory for a parent node that only has children.
-    /// Example: <c>FileType.Parent("Source Code", dotnet, java)</c>
-    /// </summary>
-    public static FileType Parent(string name, params FileType[]? children) =>
-        new(name, [], children ?? []);
-
-    /// <summary>
-    /// Factory for a composite node that has its own extensions in addition to children.
-    /// </summary>
-    public static FileType Composite(string name, string[] extensions, params FileType[] children) =>
-        new(name, extensions, children);
-
-    /// <summary>
-    /// Collects all extensions for this type, including children.
-    /// </summary>
-    public IEnumerable<string> FlattenExtensions()
-    {
-        return this.FilterExtensions
-            .Concat(this.Children.SelectMany(child => child.FlattenExtensions()))
-            .Distinct(StringComparer.OrdinalIgnoreCase);
-    }
-}

app/MindWork AI Studio/Tools/Rust/FileTypeFilter.cs

@@ -2,43 +2,75 @@ namespace AIStudio.Tools.Rust;
 
 /// <summary>
 /// Represents a file type that can optionally contain child file types.
-/// Use the static helpers <see cref="Leaf"/>, <see cref="Parent"/> and <see cref="Composite"/> to build readable trees.
+/// Use the static helpers Leaf, Parent, Composite, ByFileName, and ByFileNamePrefix to build readable trees.
 /// </summary>
+/// <remarks>
+/// File names are kept apart from the extensions: a native file picker filters by extension only, and
+/// a file name such as Dockerfile is no extension of any file.
+/// </remarks>
 /// <param name="FilterName">Display name of the type (e.g., "Document").</param>
 /// <param name="FilterExtensions">File extensions belonging to this type (without dot).</param>
 /// <param name="Children">Nested file types that are included when this type is selected.</param>
-public sealed record FileTypeFilter(string FilterName, string[] FilterExtensions, IReadOnlyList<FileTypeFilter> Children)
+/// <param name="FileNames">Complete file names belonging to this type (e.g., "Makefile").</param>
+/// <param name="FileNamePrefixes">Beginnings of file names belonging to this type (e.g., "Dockerfile" for "Dockerfile.development").</param>
+public sealed record FileTypeFilter(string FilterName, string[] FilterExtensions, IReadOnlyList<FileTypeFilter> Children, string[] FileNames, string[] FileNamePrefixes)
 {
     /// <summary>
     /// Factory for a leaf node.
-    /// Example: <c>FileType.Leaf(".NET", "cs", "razor")</c>
+    /// Example: <c>FileTypeFilter.Leaf(".NET", "cs", "razor")</c>
     /// </summary>
     public static FileTypeFilter Leaf(string name, params string[] extensions) =>
-        new(name, extensions, []);
+        new(name, extensions, [], [], []);
 
     /// <summary>
     /// Factory for a parent node that only has children.
-    /// Example: <c>FileType.Parent("Source Code", dotnet, java)</c>
+    /// Example: <c>FileTypeFilter.Parent("Source Code", dotnet, java)</c>
     /// </summary>
     public static FileTypeFilter Parent(string name, params FileTypeFilter[]? children) =>
-        new(name, [], children ?? []);
+        new(name, [], children ?? [], [], []);
 
     /// <summary>
     /// Factory for a composite node that has its own extensions in addition to children.
     /// </summary>
     public static FileTypeFilter Composite(string name, string[] extensions, params FileTypeFilter[] children) =>
-        new(name, extensions, children);
-    
+        new(name, extensions, children, [], []);
+
+    /// <summary>
+    /// Factory for a leaf node that matches complete file names instead of extensions.
+    /// Example: <c>FileTypeFilter.ByFileName("Build files", "Makefile", "BUILD")</c>
+    /// </summary>
+    public static FileTypeFilter ByFileName(string name, params string[] fileNames) =>
+        new(name, [], [], fileNames, []);
+
+    /// <summary>
+    /// Factory for a leaf node that matches the beginning of file names instead of extensions.
+    /// Example: <c>FileTypeFilter.ByFileNamePrefix("Container files", "Dockerfile", "Containerfile")</c>
+    /// </summary>
+    public static FileTypeFilter ByFileNamePrefix(string name, params string[] prefixes) =>
+        new(name, [], [], [], prefixes);
+
     /// <summary>
     /// Collects all extensions for this type, including children.
     /// </summary>
-    public IEnumerable<string> FlattenExtensions()
+    public IEnumerable<string> FlattenExtensions() => this.Flatten(type => type.FilterExtensions);
+
+    /// <summary>
+    /// Collects all complete file names for this type, including children.
+    /// </summary>
+    public IEnumerable<string> FlattenFileNames() => this.Flatten(type => type.FileNames);
+
+    /// <summary>
+    /// Collects all file name prefixes for this type, including children.
+    /// </summary>
+    public IEnumerable<string> FlattenFileNamePrefixes() => this.Flatten(type => type.FileNamePrefixes);
+
+    private IEnumerable<string> Flatten(Func<FileTypeFilter, string[]> select)
     {
-        return this.FilterExtensions
-            .Concat(this.Children.SelectMany(child => child.FlattenExtensions()))
+        return select(this)
+            .Concat(this.Children.SelectMany(child => child.Flatten(select)))
             .Distinct(StringComparer.OrdinalIgnoreCase);
     }
-    
+
     public bool ContainsType(FileTypeFilter target)
     {
         if (this == target)

app/MindWork AI Studio/Tools/Rust/FileTypes.cs

@@ -13,12 +13,12 @@ public static class FileTypes
 {
     private static string TB(string fallbackEn) => I18N.I.T(fallbackEn, typeof(FileTypes).Namespace, nameof(FileTypes));
     
-    public static readonly FileTypeFilter SOURCE_LIKE_FILE_NAMES = FileTypeFilter.Leaf(TB("Source like"),
+    public static readonly FileTypeFilter SOURCE_LIKE_FILE_NAMES = FileTypeFilter.ByFileName(TB("Source like"),
         "Dockerfile", "Containerfile", "Jenkinsfile", "Makefile", "GNUmakefile", "Procfile", "Vagrantfile",
         "Tiltfile", "Justfile", "Brewfile", "Caddyfile", "Gemfile", "Podfile", "Fastfile", "Appfile", "Rakefile", "Dangerfile",
         "BUILD", "WORKSPACE", "BUCK");
 
-    public static readonly FileTypeFilter SOURCE_LIKE_FILE_NAME_PREFIXES = FileTypeFilter.Leaf(TB("Source like prefix"),
+    public static readonly FileTypeFilter SOURCE_LIKE_FILE_NAME_PREFIXES = FileTypeFilter.ByFileNamePrefix(TB("Source like prefix"),
         "Dockerfile", "Containerfile", "Jenkinsfile", "Procfile", "Caddyfile");
     
     // Source code hierarchy: SourceCode -> (.NET, Java, Python, Web, C/C++, Config, ...)
@@ -138,15 +138,29 @@ public static class FileTypes
     /// <returns>True, when reading the file needs Pandoc.</returns>
     public static bool RequiresPandoc(string filePath) => IsAllowedPath(filePath, PANDOC_CONVERTED);
 
-    public static FileTypeFilter? AsOneFileType(params FileTypeFilter[]? types)
+    /// <summary>
+    /// Turns the given file types into the one flat filter a native file dialog takes.
+    /// </summary>
+    /// <remarks>
+    /// The filter holds the extensions of all given types and of their children. It is named after
+    /// the type when there is only one. Files recognized by their name or content only, such as
+    /// Dockerfile or LICENSE, cannot be expressed by extension: the dialog does not offer them once
+    /// other types narrow the list, whereas drag and drop accepts them. When no extension remains at
+    /// all, there is no filter, the dialog shows every file, and the caller checks the selection
+    /// with IsAllowedPath.
+    /// </remarks>
+    /// <param name="types">The file types to show, or none for all files.</param>
+    /// <returns>The filter, or null when the dialog should show all files.</returns>
+    public static FileDialogFilter? ToFileDialogFilter(params FileTypeFilter[]? types)
     {
         if (types == null || types.Length == 0)
             return null;
-        
-        if (types.Length == 1)
-            return types[0];
 
-        return FileTypeFilter.Composite(TB("Custom"), OnlyAllowTypes(types));
+        var extensions = OnlyAllowTypes(types);
+        if (extensions.Length == 0)
+            return null;
+
+        return new FileDialogFilter(types.Length == 1 ? types[0].FilterName : TB("Custom"), extensions);
     }
     
     public static string[] OnlyAllowTypes(params FileTypeFilter[] types)
@@ -155,7 +169,6 @@ public static class FileTypes
             return [];
 
         return types
-            .Where(t => t != SOURCE_LIKE_FILE_NAMES && t != SOURCE_LIKE_FILE_NAME_PREFIXES)
             .SelectMany(t => t.FlattenExtensions())
             .Select(ext => ext.ToLowerInvariant())
             .Distinct(StringComparer.OrdinalIgnoreCase)
@@ -192,16 +205,11 @@ public static class FileTypes
         if (string.IsNullOrWhiteSpace(fileName))
             return false;
 
-        if (types.Any(t => t.ContainsType(SOURCE_LIKE_FILE_NAMES)))
-        { 
-            if (SOURCE_LIKE_FILE_NAMES.FilterExtensions.Contains(fileName, StringComparer.OrdinalIgnoreCase))
-                return true;
-        }
-        
-        if (types.Any(t => t.ContainsType(SOURCE_LIKE_FILE_NAME_PREFIXES))){
-            if (SOURCE_LIKE_FILE_NAME_PREFIXES.FilterExtensions.Any(prefix => fileName.StartsWith(prefix, StringComparison.OrdinalIgnoreCase)))
-                return true;
-        }
+        if (types.SelectMany(t => t.FlattenFileNames()).Contains(fileName, StringComparer.OrdinalIgnoreCase))
+            return true;
+
+        if (types.SelectMany(t => t.FlattenFileNamePrefixes()).Any(prefix => fileName.StartsWith(prefix, StringComparison.OrdinalIgnoreCase)))
+            return true;
 
         if (types.Any(type => type.ContainsType(READABLE_TEXT)) && ReadableTextDetection.IsReadableTextFile(filePath))
             return true;

app/MindWork AI Studio/Tools/Rust/SaveFileOptions.cs

@@ -6,5 +6,5 @@ public class SaveFileOptions
     
     public PreviousFile? PreviousFile { get; init; }
 
-    public FileTypeFilter? Filter { get; init; }
+    public FileDialogFilter? Filter { get; init; }
 }

app/MindWork AI Studio/Tools/Rust/SelectFileOptions.cs

@@ -6,5 +6,5 @@ public sealed class SelectFileOptions
     
     public PreviousFile? PreviousFile { get; init; }
 
-    public FileTypeFilter? Filter { get; init; }
+    public FileDialogFilter? Filter { get; init; }
 }

app/MindWork AI Studio/Tools/Services/FileEnumerationResult.cs

@@ -77,7 +77,7 @@ public sealed class FileEnumerationResult
             return extension;
 
         var fileName = Path.GetFileName(filePath);
-        return FileTypes.SOURCE_LIKE_FILE_NAMES.FilterExtensions
+        return FileTypes.SOURCE_LIKE_FILE_NAMES.FileNames
             .FirstOrDefault(knownFileName => string.Equals(knownFileName, fileName, StringComparison.OrdinalIgnoreCase))
             ?? string.Empty;
     }

app/MindWork AI Studio/Tools/Services/RustService.FileSystem.cs

@@ -58,7 +58,7 @@ public sealed partial class RustService
                 {
                     Title = title,
                     PreviousFile = initialFile is null ? null : new (initialFile),
-                    Filter = FileTypes.AsOneFileType(filter)
+                    Filter = FileTypes.ToFileDialogFilter(filter)
                 };
 
                 var result = await this.http.PostAsJsonAsync("/select/file", payload, this.jsonRustSerializerOptions);
@@ -81,7 +81,7 @@ public sealed partial class RustService
                 {
                     Title = title,
                     PreviousFile = initialFile is null ? null : new (initialFile),
-                    Filter = FileTypes.AsOneFileType(filter)
+                    Filter = FileTypes.ToFileDialogFilter(filter)
                 };
 
                 var result = await this.http.PostAsJsonAsync("/select/files", payload, this.jsonRustSerializerOptions);
@@ -112,7 +112,7 @@ public sealed partial class RustService
                 {
                     Title = title,
                     PreviousFile = initialFile is null ? null : new (initialFile),
-                    Filter = FileTypes.AsOneFileType(filter)
+                    Filter = FileTypes.ToFileDialogFilter(filter)
                 };
 
                 var result = await this.http.PostAsJsonAsync("/save/file", payload, this.jsonRustSerializerOptions);

app/Tests/Tools/FileTypesTests.cs

@@ -1,4 +1,6 @@
+using System.Reflection;
 using System.Text;
+using System.Text.Json;
 
 using AIStudio.Tools.Rust;
 using AIStudio.Tools.Validation;
@@ -26,6 +28,105 @@ public class FileTypesTests
         Assert.That(FileTypes.IsAllowedPath(path, FileTypes.DOCUMENT), Is.True);
     }
 
+    [TestCase("build")]
+    [TestCase("dockerfile")]
+    [TestCase("makefile")]
+    [TestCase("workspace")]
+    public void FileNamesAreNoExtensions(string extension)
+    {
+        Assert.Multiple(() =>
+        {
+            Assert.That(FileTypes.IsAllowedExtension(extension, FileTypes.DOCUMENT), Is.False);
+            Assert.That(FileTypes.IsAllowedExtension(extension, FileTypes.SOURCE_CODE), Is.False);
+        });
+    }
+
+    [Test]
+    public void FlattenedExtensionsHoldNoFileNames()
+    {
+        var fileNames = FileTypes.SOURCE_LIKE_FILE_NAMES.FileNames.Concat(FileTypes.SOURCE_LIKE_FILE_NAME_PREFIXES.FileNamePrefixes);
+
+        Assert.That(FileTypes.OnlyAllowTypes(FileTypes.DOCUMENT).Intersect(fileNames, StringComparer.OrdinalIgnoreCase), Is.Empty);
+    }
+
+    [Test]
+    public void EveryExtensionIsLowercaseWithoutDot()
+    {
+        var extensions = typeof(FileTypes)
+            .GetFields(BindingFlags.Public | BindingFlags.NonPublic | BindingFlags.Static)
+            .Where(field => field.FieldType == typeof(FileTypeFilter))
+            .SelectMany(field => ((FileTypeFilter)field.GetValue(null)!).FlattenExtensions())
+            .ToArray();
+
+        Assert.That(extensions, Is.Not.Empty);
+        Assert.That(extensions, Has.All.Matches<string>(extension => extension == extension.ToLowerInvariant() && !extension.Contains('.')));
+    }
+
+    [Test]
+    public void DialogFilterOfAParentHoldsTheExtensionsOfItsChildren()
+    {
+        var filter = FileTypes.ToFileDialogFilter(FileTypes.DOCUMENT);
+        var fileNames = FileTypes.SOURCE_LIKE_FILE_NAMES.FileNames.Concat(FileTypes.SOURCE_LIKE_FILE_NAME_PREFIXES.FileNamePrefixes);
+
+        Assert.That(filter, Is.Not.Null);
+        Assert.Multiple(() =>
+        {
+            Assert.That(filter!.FilterName, Is.EqualTo(FileTypes.DOCUMENT.FilterName));
+            Assert.That(filter.FilterExtensions, Is.SupersetOf(new[] { "pdf", "docx", "xlsx", "cs", "csv", "txt", "tex" }));
+            Assert.That(filter.FilterExtensions.Intersect(fileNames, StringComparer.OrdinalIgnoreCase), Is.Empty);
+        });
+    }
+
+    [Test]
+    public void DialogFilterOfTextHoldsOnlyItsExtensions()
+    {
+        var filter = FileTypes.ToFileDialogFilter(FileTypes.TEXT);
+
+        Assert.That(filter, Is.Not.Null);
+        Assert.Multiple(() =>
+        {
+            Assert.That(filter!.FilterName, Is.EqualTo(FileTypes.TEXT.FilterName));
+            Assert.That(filter.FilterExtensions, Is.EquivalentTo(new[] { "txt", "md", "rtf" }));
+        });
+    }
+
+    [Test]
+    public void DialogFilterOfOneLeafKeepsItsName()
+    {
+        var filter = FileTypes.ToFileDialogFilter(FileTypes.JSON);
+        var combinedFilter = FileTypes.ToFileDialogFilter(FileTypes.JSON, FileTypes.CSV);
+
+        Assert.That(filter, Is.Not.Null);
+        Assert.That(combinedFilter, Is.Not.Null);
+        Assert.Multiple(() =>
+        {
+            Assert.That(filter!.FilterName, Is.EqualTo("JSON"));
+            Assert.That(filter.FilterExtensions, Is.EqualTo(new[] { "json" }));
+            Assert.That(combinedFilter!.FilterExtensions, Is.EquivalentTo(new[] { "json", "csv" }));
+        });
+    }
+
+    [Test]
+    public void TypesWithoutExtensionsGiveNoDialogFilter()
+    {
+        Assert.Multiple(() =>
+        {
+            Assert.That(FileTypes.ToFileDialogFilter(FileTypes.SOURCE_LIKE_FILE_NAMES), Is.Null);
+            Assert.That(FileTypes.ToFileDialogFilter(FileTypes.SOURCE_LIKE_FILE_NAME_PREFIXES), Is.Null);
+            Assert.That(FileTypes.ToFileDialogFilter(), Is.Null);
+            Assert.That(FileTypes.ToFileDialogFilter(null), Is.Null);
+        });
+    }
+
+    [Test]
+    public void DialogFilterMatchesTheRuntimeContract()
+    {
+        // The struct FileTypeFilter in runtime/src/file_actions.rs knows exactly these two fields:
+        var json = JsonSerializer.Serialize(FileTypes.ToFileDialogFilter(FileTypes.JSON), new JsonSerializerOptions { PropertyNamingPolicy = JsonNamingPolicy.SnakeCaseLower });
+
+        Assert.That(json, Is.EqualTo("""{"filter_name":"JSON","filter_extensions":["json"]}"""));
+    }
+
     [Test]
     public void OnlyFiltersWithReadableTextLookAtTheContent()
     {
@@ -46,14 +147,13 @@ public class FileTypesTests
     [Test]
     public void ReadableTextDoesNotChangeExtensionFilters()
     {
-        var combinedFilter = FileTypes.AsOneFileType(FileTypes.JSON, FileTypes.READABLE_TEXT);
+        var combinedFilter = FileTypes.ToFileDialogFilter(FileTypes.JSON, FileTypes.READABLE_TEXT);
 
         Assert.Multiple(() =>
         {
-            Assert.That(FileTypes.AsOneFileType(FileTypes.READABLE_TEXT), Is.SameAs(FileTypes.READABLE_TEXT));
+            Assert.That(FileTypes.ToFileDialogFilter(FileTypes.READABLE_TEXT), Is.Null);
             Assert.That(combinedFilter, Is.Not.Null);
             Assert.That(combinedFilter!.FilterExtensions, Is.EqualTo(new[] { "json" }));
-            Assert.That(FileTypes.AsOneFileType(FileTypes.JSON), Is.SameAs(FileTypes.JSON));
         });
     }
 
@@ -66,7 +166,7 @@ public class FileTypesTests
             Assert.That(FileTypes.TEXT.ContainsType(FileTypes.READABLE_TEXT), Is.True);
             Assert.That(FileTypes.DOCUMENT.Children, Does.Not.Contain(FileTypes.READABLE_TEXT));
             Assert.That(FileTypes.DOCUMENT.ContainsType(FileTypes.READABLE_TEXT), Is.True);
-            Assert.That(FileTypes.AsOneFileType(FileTypes.DOCUMENT), Is.Not.Null);
+            Assert.That(FileTypes.ToFileDialogFilter(FileTypes.DOCUMENT), Is.Not.Null);
         });
 
         AssertPath("resource \"example\" \"main\" {}", "infrastructure.tf", Encoding.UTF8, true, FileTypes.DOCUMENT);