Fix JSON error gutter markers in flet_code_editor

Author: EricFeng9

client/pubspec.lock

@@ -359,7 +359,7 @@ packages:
       path: "../packages/flet"
       relative: true
     source: path
-    version: "0.84.0"
+    version: "0.83.1"
   flet_ads:
     dependency: "direct main"
     description:
@@ -911,10 +911,10 @@ packages:
     dependency: transitive
     description:
       name: matcher
-      sha256: "12956d0ad8390bbcc63ca2e1469c0619946ccb52809807067a7020d57e647aa6"
+      sha256: dc0b7dc7651697ea4ff3e69ef44b0407ea32c487a39fff6a4004fa585e901861
       url: "https://pub.dev"
     source: hosted
-    version: "0.12.18"
+    version: "0.12.19"
   material_color_utilities:
     dependency: transitive
     description:
@@ -1628,10 +1628,10 @@ packages:
     dependency: transitive
     description:
       name: test_api
-      sha256: "93167629bfc610f71560ab9312acdda4959de4df6fac7492c89ff0d3886f6636"
+      sha256: "8161c84903fd860b26bfdefb7963b3f0b68fee7adea0f59ef805ecca346f0c7a"
       url: "https://pub.dev"
     source: hosted
-    version: "0.7.9"
+    version: "0.7.10"
   torch_light:
     dependency: transitive
     description:

sdk/python/packages/flet-code-editor/src/flutter/flet_code_editor/lib/src/utils/flet_code_controller.dart

@@ -1,14 +1,21 @@
 import 'package:flutter/widgets.dart';
 import 'package:flutter_code_editor/flutter_code_editor.dart' as fce;
+import 'package:highlight/languages/json.dart';
+
+import 'json_analyzer.dart';
 
 class FletCodeController extends fce.CodeController {
-  FletCodeController({
-    super.text,
-    super.language,
-  });
+  FletCodeController({super.text, super.language})
+    : super(analyzer: _analyzerForLanguage(language));
 
   bool autocompletionEnabled = false;
 
+  static fce.AbstractAnalyzer _analyzerForLanguage(dynamic language) {
+    return language != json
+        ? const fce.DefaultLocalAnalyzer()
+        : const JsonLocalAnalyzer();
+  }
+
   @override
   Future<void> generateSuggestions() async {
     if (!autocompletionEnabled) {
@@ -44,10 +51,7 @@ class FletCodeController extends fce.CodeController {
       extentOffset: endSelectionPosition,
     );
 
-    value = TextEditingValue(
-      text: replacedText,
-      selection: adjustedSelection,
-    );
+    value = TextEditingValue(text: replacedText, selection: adjustedSelection);
 
     popupController.hide();
   }

sdk/python/packages/flet-code-editor/src/flutter/flet_code_editor/lib/src/utils/json_analyzer.dart

@@ -0,0 +1,37 @@
+import 'dart:convert';
+
+import 'package:flutter_code_editor/flutter_code_editor.dart' as fce;
+
+class JsonLocalAnalyzer extends fce.AbstractAnalyzer {
+  const JsonLocalAnalyzer();
+
+  static const _defaultAnalyzer = fce.DefaultLocalAnalyzer();
+
+  @override
+  Future<fce.AnalysisResult> analyze(fce.Code code) async {
+    final issues = (await _defaultAnalyzer.analyze(code)).issues.toList();
+
+    if (code.text.trim().isEmpty) {
+      return fce.AnalysisResult(issues: issues);
+    }
+
+    try {
+      jsonDecode(code.text);
+    } on FormatException catch (error) {
+      issues.add(
+        fce.Issue(
+          line: _lineFromOffset(code.text, error.offset),
+          message: error.message,
+          type: fce.IssueType.error,
+        ),
+      );
+    }
+
+    return fce.AnalysisResult(issues: issues);
+  }
+
+  int _lineFromOffset(String text, int? offset) {
+    final safeOffset = (offset ?? 0).clamp(0, text.length);
+    return '\n'.allMatches(text.substring(0, safeOffset)).length;
+  }
+}

sdk/python/packages/flet-code-editor/src/flutter/flet_code_editor/test/json_gutter_analyzer_test.dart

@@ -0,0 +1,43 @@
+import 'package:flutter_code_editor/flutter_code_editor.dart' as fce;
+import 'package:flutter_test/flutter_test.dart';
+import 'package:highlight/languages/json.dart';
+
+import 'package:flet_code_editor/src/utils/flet_code_controller.dart';
+import 'package:flet_code_editor/src/utils/json_analyzer.dart';
+
+void main() {
+  group('FletCodeController JSON analyzer', () {
+    test('uses JSON analyzer for JSON language', () {
+      final controller = FletCodeController(
+        text: '{"name": "flet"}',
+        language: json,
+      );
+
+      expect(controller.analyzer, isA<JsonLocalAnalyzer>());
+    });
+
+    test('reports invalid JSON syntax as gutter issues', () async {
+      final controller = FletCodeController(
+        text: '{\n  "name": "flet"\n  "version": 1\n}',
+        language: json,
+      );
+
+      await controller.analyzeCode();
+
+      expect(controller.analysisResult.issues, hasLength(1));
+      expect(controller.analysisResult.issues.single.line, 2);
+      expect(controller.analysisResult.issues.single.type, fce.IssueType.error);
+    });
+
+    test('keeps valid JSON free of issues', () async {
+      final controller = FletCodeController(
+        text: '{\n  "name": "flet",\n  "version": 1\n}',
+        language: json,
+      );
+
+      await controller.analyzeCode();
+
+      expect(controller.analysisResult.issues, isEmpty);
+    });
+  });
+}