Generate the diagnostic pages from data files

site/lib/src/components/common/tags.dart

@@ -22,26 +22,46 @@ class Tags extends StatelessComponent {
 ///
 /// Generally displayed within a [Tags] component.
 class Tag extends StatelessComponent {
-  const Tag(this.content, {this.icon, this.title, this.label, this.color});
+  const Tag(
+    this.content, {
+    this.icon,
+    this.title,
+    this.label,
+    this.color,
+    this.link,
+  });
 
   final String content;
   final String? icon;
   final String? title;
   final String? label;
   final String? color;
+  final String? link;
 
   @override
   Component build(BuildContext context) {
+    final children = [
+      if (icon case final iconId?) MaterialIcon(iconId),
+      span([text(content)]),
+    ];
+    final attributes = {
+      'title': ?title,
+      'aria-label': ?(label ?? title),
+    };
+
+    if (link case final link?) {
+      return a(
+        href: link,
+        classes: 'tag-label',
+        attributes: attributes,
+        children,
+      );
+    }
+
     return div(
       classes: 'tag-label',
-      attributes: {
-        'title': ?title,
-        'aria-label': ?(label ?? title),
-      },
-      [
-        if (icon case final iconId?) MaterialIcon(iconId),
-        span([text(content)]),
-      ],
+      attributes: attributes,
+      children,
     );
   }
 }

site/lib/src/models/diagnostic_model.dart

@@ -0,0 +1,44 @@
+// Copyright (c) 2025, the Dart project authors. Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import 'dart:convert' show jsonDecode;
+import 'dart:io';
+
+import 'package:path/path.dart' as p;
+
+import '../util.dart';
+
+extension type DiagnosticInfo.fromJson(Map<String, Object?> info) {
+  String get id => info['id'] as String;
+  String get description => info['description'] as String;
+  String? get documentation => info['documentation'] as String?;
+  bool get hasDocumentation => info['hasDocumentation'] as bool? ?? false;
+  bool get fromLint => info['fromLint'] as bool? ?? false;
+  List<String> get previousNames =>
+      (info['previousNames'] as List<Object?>).cast<String>();
+}
+
+/// Reads and parses information about diagnostics from
+/// the `src/data/diagnostics.json` file.
+List<DiagnosticInfo> readAndLoadDiagnostics() {
+  if (_loadedDiagnostics case final alreadyLoadedDiagnostics?) {
+    return alreadyLoadedDiagnostics;
+  }
+
+  final diagnosticsFile = File(
+    p.join(siteSrcDirectoryPath, 'data', 'diagnostics.json'),
+  );
+  final rawDiagnosticInfo =
+      jsonDecode(diagnosticsFile.readAsStringSync()) as List<Object?>;
+
+  final diagnostics = rawDiagnosticInfo
+      .cast<Map<String, Object?>>()
+      .map(DiagnosticInfo.fromJson)
+      .toList(growable: false);
+
+  return _loadedDiagnostics = diagnostics;
+}
+
+/// A cache of the loaded and parsed diagnostic info.
+List<DiagnosticInfo>? _loadedDiagnostics;