enhancement(marketplace): database drivers preview-only in Extensions UI

lib/core/extensions/extension_support.dart

@@ -0,0 +1,52 @@
+import 'dart:io';
+
+import 'package:path/path.dart' as p;
+import 'package:querya_desktop/core/extensions/models/extension_manifest.dart';
+import 'package:querya_desktop/core/extensions/models/extension_type.dart';
+import 'package:querya_desktop/core/market/marketplace_repository.dart';
+
+/// Support matrix for locally installed / marketplace extensions.
+///
+/// Themes install and apply fully. Database drivers are catalog preview until
+/// the dynamic plugin runtime ships (see Marketplace API roadmap).
+class ExtensionSupport {
+  ExtensionSupport._();
+
+  static const databaseDriverPreviewNotice =
+      'Database drivers in the Marketplace are preview listings only. '
+      'Querya connects using built-in Dart drivers (PostgreSQL, MySQL, SQLite, '
+      'Redis, MongoDB). External driver plugins will load via the Marketplace '
+      'plugin runtime in a future release.';
+
+  static const databaseDriverMissingEntryMessage =
+      'Driver package is missing its main entry file. Installation aborted.';
+
+  static bool isPreviewOnly(ExtensionType type) =>
+      type == ExtensionType.databaseDriver;
+
+  static bool isPreviewOnlyManifest(ExtensionManifest manifest) =>
+      isPreviewOnly(manifest.type);
+
+  /// Ensures a database driver archive contains the declared [ExtensionManifest.main].
+  static void validateDriverPackage({
+    required ExtensionManifest manifest,
+    required Directory installDir,
+  }) {
+    if (manifest.type != ExtensionType.databaseDriver) return;
+
+    final main = manifest.main?.trim();
+    if (main == null || main.isEmpty) {
+      throw MarketplaceException(
+        'Driver "${manifest.id}" is missing a main entry in manifest.json.',
+      );
+    }
+
+    final entry = File(p.join(installDir.path, main));
+    if (!entry.existsSync()) {
+      throw MarketplaceException(
+        'Driver package "${manifest.id}" is missing entry file "$main". '
+        '$databaseDriverMissingEntryMessage',
+      );
+    }
+  }
+}

lib/core/market/http_marketplace_repository.dart

@@ -5,19 +5,13 @@ import 'package:archive/archive.dart';
 import 'package:crypto/crypto.dart';
 import 'package:http/http.dart' as http;
 import 'package:path/path.dart' as p;
+import 'package:querya_desktop/core/extensions/extension_support.dart';
 import 'package:querya_desktop/core/extensions/extension_paths.dart';
 import 'package:querya_desktop/core/extensions/local_extension_registry.dart';
 import 'package:querya_desktop/core/extensions/models/extension_manifest.dart';
 import 'package:querya_desktop/core/extensions/models/extension_type.dart';
 import 'marketplace_repository.dart';
 
-class MarketplaceException implements Exception {
-  MarketplaceException(this.message);
-  final String message;
-  @override
-  String toString() => 'MarketplaceException: $message';
-}
-
 /// HTTP implementation of [MarketplaceRepository] connecting to MarketApi backend.
 ///
 /// Implements secure downloading with SHA256 checksum verification and safe
@@ -104,6 +98,10 @@ class HttpMarketplaceRepository implements MarketplaceRepository {
     ExtensionManifest manifest, {
     void Function(double)? onProgress,
   }) async {
+    if (ExtensionSupport.isPreviewOnly(manifest.type)) {
+      throw MarketplaceException(ExtensionSupport.databaseDriverPreviewNotice);
+    }
+
     final downloadUrl = manifest.downloadUrl;
     if (downloadUrl == null || downloadUrl.trim().isEmpty) {
       throw MarketplaceException('Extension manifest is missing downloadUrl');
@@ -165,6 +163,11 @@ class HttpMarketplaceRepository implements MarketplaceRepository {
 
       onProgress?.call(0.95);
 
+      ExtensionSupport.validateDriverPackage(
+        manifest: manifest,
+        installDir: extDir,
+      );
+
       // Step 4: Write/Update manifest.json in the extension directory
       final manifestFile = File(p.join(extDir.path, 'manifest.json'));
       const encoder = JsonEncoder.withIndent('  ');

lib/core/market/marketplace_repository.dart

@@ -2,13 +2,22 @@ import 'dart:async';
 import 'dart:convert';
 import 'dart:io';
 import 'package:path/path.dart' as p;
+import 'package:querya_desktop/core/extensions/extension_support.dart';
 import 'package:querya_desktop/core/extensions/extension_paths.dart';
 import 'package:querya_desktop/core/extensions/local_extension_registry.dart';
 import 'package:querya_desktop/core/extensions/models/extension_manifest.dart';
 import 'package:querya_desktop/core/extensions/models/extension_type.dart';
 
 export 'http_marketplace_repository.dart';
 
+/// Thrown when marketplace install, download, or validation fails.
+class MarketplaceException implements Exception {
+  MarketplaceException(this.message);
+  final String message;
+  @override
+  String toString() => 'MarketplaceException: $message';
+}
+
 /// Abstract repository contract for Marketplace operations (Block B).
 ///
 /// See [docs/market-tech.md] and Block B specification.
@@ -175,6 +184,10 @@ class MockMarketplaceRepository implements MarketplaceRepository {
     ExtensionManifest manifest, {
     void Function(double)? onProgress,
   }) async {
+    if (ExtensionSupport.isPreviewOnly(manifest.type)) {
+      throw MarketplaceException(ExtensionSupport.databaseDriverPreviewNotice);
+    }
+
     // Simulate download & verification progress
     for (int i = 1; i <= 10; i++) {
       await Future.delayed(const Duration(milliseconds: 100));

lib/features/extensions/presentation/pages/extension_manager_dialog.dart

@@ -1,4 +1,5 @@
 import 'package:flutter/material.dart' as material;
+import 'package:querya_desktop/core/extensions/extension_support.dart';
 import 'package:querya_desktop/core/extensions/local_extension_registry.dart';
 import 'package:querya_desktop/core/extensions/models/extension_manifest.dart';
 import 'package:querya_desktop/core/layout/window_layout.dart';
@@ -82,6 +83,12 @@ class _ExtensionManagerContentState extends material.State<_ExtensionManagerCont
     } catch (e) {
       if (mounted) {
         setState(() => _installingProgress.remove(manifest.id));
+        final message = e is MarketplaceException
+            ? e.message
+            : 'Failed to install "${manifest.name}".';
+        material.ScaffoldMessenger.of(context).showSnackBar(
+          material.SnackBar(content: material.Text(message)),
+        );
       }
     }
   }
@@ -234,8 +241,37 @@ class _ExtensionManagerContentState extends material.State<_ExtensionManagerCont
         child: material.CircularProgressIndicator(),
       );
     }
+    final theme = Theme.of(context).colorScheme;
     return material.Column(
       children: [
+        material.Padding(
+          padding: const material.EdgeInsets.fromLTRB(24, 16, 24, 0),
+          child: material.Container(
+            width: double.infinity,
+            padding: const material.EdgeInsets.all(12),
+            decoration: material.BoxDecoration(
+              color: theme.muted.withValues(alpha: 0.35),
+              borderRadius: material.BorderRadius.circular(8),
+              border: material.Border.all(color: theme.border),
+            ),
+            child: material.Row(
+              crossAxisAlignment: material.CrossAxisAlignment.start,
+              children: [
+                material.Icon(
+                  material.Icons.info_outline_rounded,
+                  size: 18,
+                  color: theme.mutedForeground,
+                ),
+                const material.SizedBox(width: 10),
+                material.Expanded(
+                  child: const Text(ExtensionSupport.databaseDriverPreviewNotice)
+                      .muted()
+                      .small(),
+                ),
+              ],
+            ),
+          ),
+        ),
         material.Padding(
           padding: const material.EdgeInsets.fromLTRB(24, 16, 24, 8),
           child: TextField(

lib/features/extensions/presentation/widgets/extension_card.dart

@@ -1,4 +1,5 @@
 import 'package:flutter/material.dart' as material;
+import 'package:querya_desktop/core/extensions/extension_support.dart';
 import 'package:querya_desktop/core/extensions/models/extension_manifest.dart';
 import 'package:querya_desktop/core/extensions/models/extension_type.dart';
 import 'package:querya_desktop/shared/widgets/widgets.dart';
@@ -29,6 +30,7 @@ class ExtensionCard extends material.StatelessWidget {
   material.Widget build(material.BuildContext context) {
     final theme = Theme.of(context).colorScheme;
     final radius = Theme.of(context).radiusMd;
+    final isPreview = ExtensionSupport.isPreviewOnlyManifest(manifest);
 
     return material.Container(
       padding: const material.EdgeInsets.all(16),
@@ -51,6 +53,10 @@ class ExtensionCard extends material.StatelessWidget {
                     material.Expanded(
                       child: Text(manifest.name).large().semiBold(),
                     ),
+                    if (isPreview) ...[
+                      const material.SizedBox(width: 8),
+                      _buildPreviewBadge(theme),
+                    ],
                   ],
                 ),
                 const material.SizedBox(height: 4),
@@ -130,6 +136,14 @@ class ExtensionCard extends material.StatelessWidget {
                   onPressed: onUninstall,
                   child: const Text('Uninstall'),
                 )
+              else if (isPreview)
+                const material.Tooltip(
+                  message: ExtensionSupport.databaseDriverPreviewNotice,
+                  child: OutlineButton(
+                    onPressed: null,
+                    child: Text('Preview'),
+                  ),
+                )
               else
                 PrimaryButton(
                   onPressed: onInstall,
@@ -160,6 +174,25 @@ class ExtensionCard extends material.StatelessWidget {
     );
   }
 
+  material.Widget _buildPreviewBadge(ColorScheme theme) {
+    return material.Container(
+      padding: const material.EdgeInsets.symmetric(horizontal: 8, vertical: 4),
+      decoration: material.BoxDecoration(
+        color: theme.muted,
+        borderRadius: material.BorderRadius.circular(6),
+        border: material.Border.all(color: theme.border),
+      ),
+      child: material.Text(
+        'Preview',
+        style: material.TextStyle(
+          fontSize: 11,
+          fontWeight: material.FontWeight.w600,
+          color: theme.mutedForeground,
+        ),
+      ),
+    );
+  }
+
   material.Widget _buildTagBadge(ColorScheme theme, String tag) {
     return material.Container(
       padding: const material.EdgeInsets.symmetric(horizontal: 6, vertical: 2),

test/core/extensions/extension_support_test.dart

@@ -0,0 +1,56 @@
+import 'dart:io';
+
+import 'package:flutter_test/flutter_test.dart';
+import 'package:path/path.dart' as p;
+import 'package:querya_desktop/core/extensions/extension_support.dart';
+import 'package:querya_desktop/core/extensions/models/extension_manifest.dart';
+import 'package:querya_desktop/core/extensions/models/extension_type.dart';
+import 'package:querya_desktop/core/market/marketplace_repository.dart';
+
+void main() {
+  group('ExtensionSupport', () {
+    test('marks database drivers as preview-only', () {
+      expect(
+        ExtensionSupport.isPreviewOnly(ExtensionType.databaseDriver),
+        isTrue,
+      );
+      expect(ExtensionSupport.isPreviewOnly(ExtensionType.theme), isFalse);
+    });
+
+    test('validateDriverPackage requires main entry file', () async {
+      final dir = await Directory.systemTemp.createTemp('querya_driver_test_');
+      addTearDown(() async {
+        if (await dir.exists()) {
+          await dir.delete(recursive: true);
+        }
+      });
+
+      const manifest = ExtensionManifest(
+        id: 'test.driver',
+        name: 'Test Driver',
+        version: '1.0.0',
+        publisher: 'Test',
+        type: ExtensionType.databaseDriver,
+        engines: {'querya_desktop': '^0.4.7'},
+        main: 'index.js',
+      );
+
+      expect(
+        () => ExtensionSupport.validateDriverPackage(
+          manifest: manifest,
+          installDir: dir,
+        ),
+        throwsA(isA<MarketplaceException>()),
+      );
+
+      await File(p.join(dir.path, 'index.js')).writeAsString('// stub');
+      expect(
+        () => ExtensionSupport.validateDriverPackage(
+          manifest: manifest,
+          installDir: dir,
+        ),
+        returnsNormally,
+      );
+    });
+  });
+}

test/core/market/marketplace_repository_test.dart

@@ -52,35 +52,24 @@ void main() {
       expect(empty, isEmpty);
     });
 
-    test('install writes manifest to disk and reloads LocalExtensionRegistry', () async {
+    test('install rejects preview database drivers', () async {
       final repo = MockMarketplaceRepository();
       final trending = await repo.getTrending();
       final target = trending.firstWhere((e) => e.id == 'queryahub.clickhouse-driver');
 
-      final progressValues = <double>[];
-      await repo.install(target, onProgress: (p) => progressValues.add(p));
-
-      expect(progressValues, isNotEmpty);
-      expect(progressValues.last, 1.0);
-
-      expect(LocalExtensionRegistry.instance.manifests.any((e) => e.id == target.id), isTrue);
-
-      final extDir = Directory(p.join(tempDir.path, target.id));
-      expect(await extDir.exists(), isTrue);
-      expect(await File(p.join(extDir.path, 'manifest.json')).exists(), isTrue);
-    });
-
-    test('uninstall removes directory and updates LocalExtensionRegistry', () async {
-      final repo = MockMarketplaceRepository();
-      final trending = await repo.getTrending();
-      final target = trending.firstWhere((e) => e.id == 'queryahub.clickhouse-driver');
-
-      await repo.install(target);
-      expect(LocalExtensionRegistry.instance.manifests.any((e) => e.id == target.id), isTrue);
+      expect(
+        () => repo.install(target),
+        throwsA(isA<MarketplaceException>().having(
+          (e) => e.message,
+          'message',
+          contains('preview listings only'),
+        )),
+      );
 
-      await repo.uninstall(target.id);
-      expect(LocalExtensionRegistry.instance.manifests.any((e) => e.id == target.id), isFalse);
-      expect(await Directory(p.join(tempDir.path, target.id)).exists(), isFalse);
+      expect(
+        LocalExtensionRegistry.instance.manifests.any((e) => e.id == target.id),
+        isFalse,
+      );
     });
 
     test('install theme creates theme.json in extension directory', () async {
@@ -218,6 +207,38 @@ void main() {
         )),
       );
     });
+    test('install rejects preview database drivers', () async {
+      final archive = Archive();
+      archive.addFile(ArchiveFile('index.js', 4, utf8.encode('stub')));
+      final zipBytes = ZipEncoder().encode(archive);
+      final expectedSha256 = sha256.convert(zipBytes).toString();
+
+      final mockClient = MockClient((request) async {
+        return http.Response.bytes(zipBytes, 200);
+      });
+
+      final repo = HttpMarketplaceRepository(client: mockClient);
+      final manifest = ExtensionManifest(
+        id: 'test.driver',
+        name: 'Driver Test',
+        version: '1.0.0',
+        publisher: 'Test',
+        type: ExtensionType.databaseDriver,
+        engines: const {'querya_desktop': '*'},
+        main: 'index.js',
+        downloadUrl: 'http://localhost:8000/driver.zip',
+        sha256Checksum: expectedSha256,
+      );
+
+      expect(
+        () => repo.install(manifest),
+        throwsA(isA<MarketplaceException>().having(
+          (e) => e.message,
+          'message',
+          contains('preview listings only'),
+        )),
+      );
+    });
   });
 }