fix: preserve inline image title attribute and remove dead code

CHANGELOG.md

@@ -1,3 +1,21 @@
+## Next
+
+### Fixed
+
+* Fix inline images losing `title` attribute when rendered inside paragraphs or list items (e.g., `![alt](src "title")`).
+* Fix redundant O(n) key lookup per entry in YAML map formatting.
+* Fix hardcoded 4-space checkbox continuation indent to use actual prefix length.
+
+### Changed
+
+* Remove unused normalization functions from `normalizer.dart` (`normalizeEmphasis`, `normalizeHorizontalRule`, `normalizeUnorderedListMarker`, `orderedListContentIndent`, `normalizeCodeFence`) — these were superseded by AST-based formatting.
+* Remove unused utility functions from `text_utils.dart` (`displayWidth`, `indent`, `repeat`, `trimTrailingWhitespace`).
+
+### Added
+
+* Add idempotency integration tests for Markdown and YAML formatting.
+* Add integration test for inline image `title` attribute in list items.
+
 ## 1.4.4
 
 ### Refactored

lib/src/markdown/ast_printer.dart

@@ -219,7 +219,7 @@ class MarkdownPrinter {
         for (var i = 1; i < lines.length; i++) {
           _writeIndent();
           if (prefix.isNotEmpty) {
-            _write('    '); // Indent for checkbox
+            _write(' ' * prefix.length); // Indent for checkbox
           }
           _writeLine(lines[i]);
         }
@@ -270,7 +270,7 @@ class MarkdownPrinter {
         for (var i = 1; i < lines.length; i++) {
           _writeIndent();
           if (prefix.isNotEmpty) {
-            _write('    '); // Indent for checkbox
+            _write(' ' * prefix.length); // Indent for checkbox
           }
           _writeLine(lines[i]);
         }
@@ -601,6 +601,10 @@ class MarkdownPrinter {
         case 'img':
           final src = node.attributes['src'] ?? '';
           final alt = node.attributes['alt'] ?? '';
+          final title = node.attributes['title'];
+          if (title != null) {
+            return '![$alt]($src "$title")';
+          }
           return '![$alt]($src)';
         case 'br':
           return '  \n';

lib/src/markdown/normalizer.dart

@@ -3,100 +3,6 @@
 /// Implements Prettier-style normalization for Markdown elements.
 library;
 
-/// Normalizes emphasis markers from `*` to `_` where appropriate.
-///
-/// Following Prettier's convention:
-/// - `*text*` becomes `_text_`
-/// - `**text**` stays as `**text**` (strong emphasis)
-/// - `***text***` becomes `_**text**_` or `**_text_**`
-/// - Emphasis within words stays as-is (e.g., `foo*bar*baz`)
-String normalizeEmphasis(String text) {
-  // Pattern for emphasis not within words:
-  // - Start of string or non-word character before `*`
-  // - `*content*` where content doesn't contain unescaped `*`
-  // - End of string or non-word character after `*`
-
-  // Handle single emphasis: *text* -> _text_
-  // Only convert when not part of a word (word boundaries)
-  final singleEmphasisPattern = RegExp(r'(?<![*\w])(\*)([^*\n]+?)\1(?![*\w])');
-
-  var result = text;
-
-  // Replace *text* with _text_ when at word boundaries
-  result = result.replaceAllMapped(singleEmphasisPattern, (match) {
-    final content = match.group(2)!;
-    // Don't convert if content starts or ends with space
-    if (content.startsWith(' ') || content.endsWith(' ')) {
-      return match.group(0)!;
-    }
-    return '_${content}_';
-  });
-
-  // Handle ***text*** -> **_text_** (bold + italic)
-  final boldItalicPattern = RegExp(
-    r'(?<![*\w])\*\*\*([^*\n]+?)\*\*\*(?![*\w])',
-  );
-  result = result.replaceAllMapped(boldItalicPattern, (match) {
-    final content = match.group(1)!;
-    return '**_${content}_**';
-  });
-
-  return result;
-}
-
-/// Normalizes horizontal rules to `---`.
-///
-/// Converts various horizontal rule styles:
-/// - `***`, `* * *` -> `---`
-/// - `___`, `_ _ _` -> `---`
-/// - `---`, `- - -` -> `---`
-String normalizeHorizontalRule(String text) {
-  // Match various horizontal rule patterns
-  final hrPattern = RegExp(
-    r'^[ \t]*([-*_])[ \t]*(?:\1[ \t]*){2,}$',
-    multiLine: true,
-  );
-
-  return text.replaceAllMapped(hrPattern, (match) => '---');
-}
-
-/// Normalizes list markers.
-///
-/// - Unordered lists: various markers (`*`, `+`) -> `-`
-/// - Ordered lists: keep numbers, normalize spacing
-String normalizeUnorderedListMarker(String marker) {
-  // Convert *, + to -
-  if (marker == '*' || marker == '+') {
-    return '-';
-  }
-  return marker;
-}
-
-/// Calculates the proper indentation for ordered list items.
-///
-/// For ordered lists, the content should align based on the widest number:
-/// ```
-/// 1. First
-/// 2. Second
-/// ...
-/// 10. Tenth (number width = 2)
-/// ```
-int orderedListContentIndent(int maxNumber, int tabWidth) {
-  final numberWidth = maxNumber.toString().length;
-  // Number + dot + space
-  return numberWidth + 2;
-}
-
-/// Normalizes a code fence marker to use backticks.
-///
-/// Converts `~~~` to ` ``` `.
-String normalizeCodeFence(String fence) {
-  if (fence.startsWith('~')) {
-    return '`' * fence.length;
-  }
-  return fence;
-}
-
 /// Normalizes heading to ATX style.
 ///
 /// Ensures consistent spacing: `# Heading` (one space after #).

lib/src/utils/text_utils.dart

@@ -47,39 +47,8 @@ String normalizeWhitespace(String text) {
   return text.replaceAll(RegExp(r'[ \t]+'), ' ').trim();
 }
 
-/// Removes trailing whitespace from each line.
-String trimTrailingWhitespace(String text) {
-  return text.split('\n').map((line) => line.trimRight()).join('\n');
-}
-
 /// Ensures the text ends with exactly one newline.
 String ensureTrailingNewline(String text) {
   final trimmed = text.trimRight();
   return trimmed.isEmpty ? '' : '$trimmed\n';
 }
-
-/// Counts the display width of a string.
-///
-/// Returns the character count (string length).
-int displayWidth(String text) {
-  return text.length;
-}
-
-/// Creates an indentation string of the specified width.
-String indent(int width, {bool useTabs = false, int tabWidth = 2}) {
-  if (width <= 0) return '';
-
-  if (useTabs) {
-    final tabs = width ~/ tabWidth;
-    final spaces = width % tabWidth;
-    return '\t' * tabs + ' ' * spaces;
-  }
-
-  return ' ' * width;
-}
-
-/// Repeats a string [count] times.
-String repeat(String text, int count) {
-  if (count <= 0) return '';
-  return text * count;
-}

lib/src/yaml/yaml_formatter.dart

@@ -187,15 +187,13 @@ class _YamlPrinter {
 
     for (var i = 0; i < sortedKeys.length; i++) {
       final key = sortedKeys[i];
-      final keyNode = map.nodes.keys.firstWhere(
-        (k) => k == key,
-      ); // Get the key node to access span
+      final keyNode = key as YamlNode;
       final valueNode = map.nodes[key]!;
 
       // Handle comments between keys, trimming leading newlines for the first key
       _printGap(
         _lastOffset,
-        (keyNode as YamlNode).span.start.offset,
+        keyNode.span.start.offset,
         trimLeadingNewlines: i == 0,
       );
 

test/markdown_integration_test.dart

@@ -231,6 +231,176 @@ Next paragraph here.
       });
     });
 
+    test('normalizes tilde code fences to backticks', () {
+      const input = '''
+~~~dart
+void main() {
+  print('Hello');
+}
+~~~
+''';
+
+      const expected = '''
+```dart
+void main() {
+  print('Hello');
+}
+```
+''';
+
+      const formatter = MarkdownFormatter();
+      expect(formatter.format(input), expected);
+    });
+
+    test('preserves inline image title attribute', () {
+      const input = '''
+Here is an image: ![alt text](image.png "Image Title")
+''';
+
+      const formatter = MarkdownFormatter();
+      final result = formatter.format(input);
+      expect(result, contains('![alt text](image.png "Image Title")'));
+    });
+
+    test('preserves inline image title in list items', () {
+      const input = '''
+* ![logo](logo.png "Logo Title")
+* Text with ![icon](icon.svg "Icon Title") inline
+''';
+
+      const formatter = MarkdownFormatter();
+      final result = formatter.format(input);
+      expect(result, contains('![logo](logo.png "Logo Title")'));
+      expect(result, contains('![icon](icon.svg "Icon Title")'));
+    });
+
+    group('Idempotency', () {
+      const formatter = MarkdownFormatter();
+
+      test('full document is idempotent', () {
+        const input = '''
+---
+title: Dapper Documentation
+author: Koji
+---
+
+# Introduction
+
+Dapper is a *fantastic* formatter.
+
+## Features
+
+- YAML formatting
+- Markdown formatting
+
+## `dapper` Usage
+
+## Code Example
+
+```dart
+void main() {
+  print('Hello');
+}
+```
+
+## Definition List
+
+Term
+: Definition
+''';
+
+        final once = formatter.format(input);
+        final twice = formatter.format(once);
+        expect(twice, once, reason: 'Formatting should be idempotent');
+      });
+
+      test('messy document is idempotent', () {
+        const input = '''
+#    Heading with spaces
+
+*   Misaligned list item
+  * Nested item
+*    Emphasis: *bold*
+
+| Column 1 | Column 2 |
+| --- | :---: |
+| Value 1 |   Value 2 |
+
+>    Blockquote with spaces
+''';
+
+        final once = formatter.format(input);
+        final twice = formatter.format(once);
+        expect(twice, once, reason: 'Formatting should be idempotent');
+      });
+
+      test('tilde code fence is idempotent', () {
+        const input = '''
+~~~dart
+void main() {
+  print('Hello');
+}
+~~~
+''';
+
+        final once = formatter.format(input);
+        final twice = formatter.format(once);
+        expect(twice, once, reason: 'Formatting should be idempotent');
+      });
+
+      test('inline image with title is idempotent', () {
+        const input = '''
+Here is ![alt](image.png "Title") in a paragraph.
+
+* ![logo](logo.png "Logo") in a list
+''';
+
+        final once = formatter.format(input);
+        final twice = formatter.format(once);
+        expect(twice, once, reason: 'Formatting should be idempotent');
+      });
+
+      test('loose list is idempotent', () {
+        const input = '''
+* **test**
+  * test
+* **test**
+  * test
+
+* **test**
+''';
+
+        final once = formatter.format(input);
+        final twice = formatter.format(once);
+        expect(twice, once, reason: 'Formatting should be idempotent');
+      });
+
+      test('nested blockquote is idempotent', () {
+        const input = '''
+> Level 1
+>> Level 2
+''';
+
+        final once = formatter.format(input);
+        final twice = formatter.format(once);
+        expect(twice, once, reason: 'Formatting should be idempotent');
+      });
+
+      test('checkbox list with code block is idempotent', () {
+        const input = '''
+- [ ] Task 1
+  ```
+  code inside
+  ```
+- [x] Task 2
+''';
+
+        final once = formatter.format(input);
+        final twice = formatter.format(once);
+        expect(twice, once, reason: 'Formatting should be idempotent');
+      });
+    });
+
     test('formats loose lists by normalizing to tight lists', () {
       const input = '''
 * **test**

test/src/markdown/ast_printer_test.dart

@@ -164,8 +164,7 @@ void main() {
       img.attributes['title'] = 'Title';
       final p = md.Element('p', [img]);
       final result = printer.print([p]);
-      // Note: Current implementation doesn't preserve title in inline rendering
-      expect(result, contains('![alt](src'));
+      expect(result, contains('![alt](src "Title")'));
     });
 
     test('prints horizontal rule', () {