fix: catch regex FormatException and show a corresponding error message

lib/l10n/intl_en.arb

@@ -128,6 +128,9 @@
   "replaceAll": "Replace all",
   "regex": "Regex",
   "caseSensitive": "Case sensitive",
+  "regexError": "Regex Error",
+  "noFindResult": "No result",
+  "emptySearchBoxHint": "Enter a pattern",
   "uploadImage": "Upload Image",
   "urlImage": "URL Image",
   "incorrectLink": "Incorrect Link",

lib/l10n/intl_zh_CN.arb

@@ -128,6 +128,9 @@
   "replaceAll": "替换全部",
   "regex": "正则表达式",
   "caseSensitive": "区分大小写",
+  "regexError": "正则错误",
+  "noFindResult": "无匹配项",
+  "emptySearchBoxHint": "输入查找内容",
   "uploadImage": "上传图片",
   "urlImage": "网络图片",
   "incorrectLink": "链接错误",

lib/l10n/intl_zh_TW.arb

@@ -128,6 +128,9 @@
   "replaceAll": "取代全部",
   "regex": "正規表示式",
   "caseSensitive": "區分大小寫",
+  "regexError": "正規錯誤",
+  "noFindResult": "無相符項",
+  "emptySearchBoxHint": "鍵入尋找内容",
   "uploadImage": "上載圖片",
   "urlImage": "網路圖片",
   "incorrectLink": "連結錯誤",

lib/src/editor/find_replace_menu/find_replace_widget.dart

@@ -161,7 +161,7 @@
 
   final findTextEditingController = TextEditingController();
 
-  String queriedPattern = '';
+  String message = AppFlowyEditorLocalizations.current.emptySearchBoxHint;
 
   bool showReplaceMenu = false;
   bool caseSensitive = false;
@@ -250,9 +250,7 @@
           padding: const EdgeInsets.symmetric(horizontal: 8.0),
           alignment: Alignment.centerLeft,
           child: Text(
-            matches.isEmpty
-                ? widget.localizations?.noResult ?? 'No Result'
-                : '$selectedIndex of ${matches.length}',
+            matches.isEmpty ? message : '$selectedIndex of ${matches.length}',
           ),
         ),
         // previous match button
@@ -322,11 +320,25 @@
   }
 
   void _searchPattern() {
-    if (findTextEditingController.text.isEmpty) {
-      return;
+    String error;
+
+    // the following line needs to be executed even if
+    // findTextEditingController.text.isEmpty, otherwise the previous
+    // matches will persist
+    error =
+        widget.searchService.findAndHighlight(findTextEditingController.text);
+
+    switch (error) {
+      case 'Regex':
+        message = AppFlowyEditorLocalizations.current.regexError;
+      case 'Empty':
+        message = AppFlowyEditorLocalizations.current.emptySearchBoxHint;
+      default:
+        message = widget.localizations?.noResult ??
+            AppFlowyEditorLocalizations.current.noFindResult;
     }
-    widget.searchService.findAndHighlight(findTextEditingController.text);
-    setState(() => queriedPattern = findTextEditingController.text);
+
+    _setState();
   }
 
   void _setState() {

lib/src/editor/find_replace_menu/search_service_v3.dart

@@ -11,8 +11,8 @@
 
   final EditorState editorState;
 
-  //matchedPositions.value will contain a list of positions of the matched patterns
-  //the position here consists of the node and the starting offset of the
+  //matchWrappers.value will contain a list of matchWrappers of the matched patterns
+  //the position here consists of the match and the node path of
   //matched pattern. We will use this to traverse between the matched patterns.
   ValueNotifier<List<MatchWrapper>> matchWrappers = ValueNotifier([]);
   SearchAlgorithm searchAlgorithm = DartBuiltIn();
@@ -75,8 +75,15 @@
 
   // Public entry method for _findAndHighlight, do necessary checks
   // and clear previous highlights before calling the private method
-  void findAndHighlight(String target, {bool unHighlight = false}) {
-    Pattern pattern = _getPattern(target);
+  String findAndHighlight(String target, {bool unHighlight = false}) {
+    Pattern pattern;
+
+    try {
+      pattern = _getPattern(target);
+    } on FormatException {
+      matchWrappers.value.clear();
+      return 'Regex';
+    }
 
     if (queriedPattern != pattern) {
       // this means we have a new pattern, but before we highlight the new matches,
@@ -87,9 +94,11 @@
       targetString = target;
     }
 
-    if (target.isEmpty) return;
+    if (target.isEmpty) return 'Empty';
 
     _findAndHighlight(pattern, unHighlight: unHighlight);
+
+    return '';
   }
 
   /// Finds the pattern in editorState.document and stores it in matchedPositions.
@@ -186,7 +195,7 @@
   /// matched word if that exists.
   Future<void> replaceSelectedWord(String replaceText) async {
     if (replaceText.isEmpty ||
-        queriedPattern.toString().isEmpty ||
+        queriedPattern.isEmpty ||
         matchWrappers.value.isEmpty) {
       return;
     }
@@ -217,7 +226,7 @@
   /// Replaces all the found occurrences of pattern with replaceText
   void replaceAllMatches(String replaceText) {
     if (replaceText.isEmpty ||
-        queriedPattern.toString().isEmpty ||
+        queriedPattern.isEmpty ||
         matchWrappers.value.isEmpty) {
       return;
     }
@@ -257,3 +266,15 @@
         end: Position(path: path, offset: match.end),
       );
 }
+
+extension on Pattern {
+  bool get isEmpty {
+    if (this is String) {
+      return (this as String).isEmpty;
+    } else if (this is RegExp) {
+      return (this as RegExp).pattern.isEmpty;
+    } else {
+      return toString().isEmpty;
+    }
+  }
+}

lib/src/l10n/intl/messages_en.dart

@@ -69,6 +69,8 @@ class MessageLookup extends MessageLookupByLibrary {
         "done": MessageLookupByLibrary.simpleMessage("Done"),
         "editLink": MessageLookupByLibrary.simpleMessage("Edit link"),
         "embedCode": MessageLookupByLibrary.simpleMessage("Embed Code"),
+        "emptySearchBoxHint":
+            MessageLookupByLibrary.simpleMessage("Enter a pattern"),
         "find": MessageLookupByLibrary.simpleMessage("Find"),
         "fontColorBlue": MessageLookupByLibrary.simpleMessage("Blue"),
         "fontColorBrown": MessageLookupByLibrary.simpleMessage("Brown"),
@@ -113,13 +115,15 @@ class MessageLookup extends MessageLookupByLibrary {
         "mobileHeading2": MessageLookupByLibrary.simpleMessage("Heading 2"),
         "mobileHeading3": MessageLookupByLibrary.simpleMessage("Heading 3"),
         "nextMatch": MessageLookupByLibrary.simpleMessage("Next match"),
+        "noFindResult": MessageLookupByLibrary.simpleMessage("No result"),
         "numberedList": MessageLookupByLibrary.simpleMessage("Numbered List"),
         "opacity": MessageLookupByLibrary.simpleMessage("Opacity"),
         "openLink": MessageLookupByLibrary.simpleMessage("Open link"),
         "paste": MessageLookupByLibrary.simpleMessage("Paste"),
         "previousMatch": MessageLookupByLibrary.simpleMessage("Previous match"),
         "quote": MessageLookupByLibrary.simpleMessage("Quote"),
         "regex": MessageLookupByLibrary.simpleMessage("Regex"),
+        "regexError": MessageLookupByLibrary.simpleMessage("Regex Error"),
         "removeLink": MessageLookupByLibrary.simpleMessage("Remove link"),
         "replace": MessageLookupByLibrary.simpleMessage("Replace"),
         "replaceAll": MessageLookupByLibrary.simpleMessage("Replace all"),

lib/src/l10n/intl/messages_zh-CN.dart

@@ -57,6 +57,7 @@ class MessageLookup extends MessageLookupByLibrary {
         "done": MessageLookupByLibrary.simpleMessage("完成"),
         "editLink": MessageLookupByLibrary.simpleMessage("修改链接"),
         "embedCode": MessageLookupByLibrary.simpleMessage("代码块"),
+        "emptySearchBoxHint": MessageLookupByLibrary.simpleMessage("输入查找内容"),
         "find": MessageLookupByLibrary.simpleMessage("查找"),
         "fontColorBlue": MessageLookupByLibrary.simpleMessage("蓝色"),
         "fontColorBrown": MessageLookupByLibrary.simpleMessage("棕色"),
@@ -97,13 +98,15 @@ class MessageLookup extends MessageLookupByLibrary {
         "mobileHeading2": MessageLookupByLibrary.simpleMessage("二级标题"),
         "mobileHeading3": MessageLookupByLibrary.simpleMessage("三级标题"),
         "nextMatch": MessageLookupByLibrary.simpleMessage("下一匹配项"),
+        "noFindResult": MessageLookupByLibrary.simpleMessage("无匹配项"),
         "numberedList": MessageLookupByLibrary.simpleMessage("有序列表"),
         "opacity": MessageLookupByLibrary.simpleMessage("透明度"),
         "openLink": MessageLookupByLibrary.simpleMessage("打开链接"),
         "paste": MessageLookupByLibrary.simpleMessage("粘贴"),
         "previousMatch": MessageLookupByLibrary.simpleMessage("上一匹配项"),
         "quote": MessageLookupByLibrary.simpleMessage("引文"),
         "regex": MessageLookupByLibrary.simpleMessage("正则表达式"),
+        "regexError": MessageLookupByLibrary.simpleMessage("正则错误"),
         "removeLink": MessageLookupByLibrary.simpleMessage("移除链接"),
         "replace": MessageLookupByLibrary.simpleMessage("替换"),
         "replaceAll": MessageLookupByLibrary.simpleMessage("替换全部"),

lib/src/l10n/intl/messages_zh-TW.dart

@@ -57,6 +57,7 @@ class MessageLookup extends MessageLookupByLibrary {
         "done": MessageLookupByLibrary.simpleMessage("完成"),
         "editLink": MessageLookupByLibrary.simpleMessage("修改連結"),
         "embedCode": MessageLookupByLibrary.simpleMessage("代碼塊"),
+        "emptySearchBoxHint": MessageLookupByLibrary.simpleMessage("鍵入尋找内容"),
         "find": MessageLookupByLibrary.simpleMessage("尋找"),
         "fontColorBlue": MessageLookupByLibrary.simpleMessage("藍色"),
         "fontColorBrown": MessageLookupByLibrary.simpleMessage("棕色"),
@@ -97,13 +98,15 @@ class MessageLookup extends MessageLookupByLibrary {
         "mobileHeading2": MessageLookupByLibrary.simpleMessage("二級標題"),
         "mobileHeading3": MessageLookupByLibrary.simpleMessage("三級標題"),
         "nextMatch": MessageLookupByLibrary.simpleMessage("下一相符項"),
+        "noFindResult": MessageLookupByLibrary.simpleMessage("無相符項"),
         "numberedList": MessageLookupByLibrary.simpleMessage("有序列表"),
         "opacity": MessageLookupByLibrary.simpleMessage("透明度"),
         "openLink": MessageLookupByLibrary.simpleMessage("打開連結"),
         "paste": MessageLookupByLibrary.simpleMessage("貼上"),
         "previousMatch": MessageLookupByLibrary.simpleMessage("上一相符項"),
         "quote": MessageLookupByLibrary.simpleMessage("引文"),
         "regex": MessageLookupByLibrary.simpleMessage("正規表示式"),
+        "regexError": MessageLookupByLibrary.simpleMessage("正規錯誤"),
         "removeLink": MessageLookupByLibrary.simpleMessage("移除連結"),
         "replace": MessageLookupByLibrary.simpleMessage("取代"),
         "replaceAll": MessageLookupByLibrary.simpleMessage("取代全部"),