From a6c6b405f1e490ee660a0d2a769d010f8c967a30 Mon Sep 17 00:00:00 2001
From: Gareth Reese <gareth@foresightmobile.com>
Date: Mon, 6 Jul 2026 10:36:53 +0100
Subject: [PATCH] Fix #132: inline builder duplicating text with multi-child
 elements
MIME-Version: 1.0
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When a custom MarkdownElementBuilder for an inline tag (e.g. `a`) returned a
widget from visitElementAfterWithContext, only current.children[0] was replaced.
If the element had multiple inline children — such as link text split on a `_`
or `*` delimiter into separate text nodes — the remaining children were still
appended to the parent, rendering the trailing text twice.

Replace all children with the returned widget (..clear()..add(child)), matching
the block-element path which already discards children. Behaviour is unchanged
for empty/single-child elements.

Adds regression tests covering `_` and `*` delimiter link text with a custom
`a` builder.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_014oVQtXCPb3bSLnL2eDwGrh
---
 CHANGELOG.md                 |  8 ++++++
 lib/src/builder.dart         | 12 +++++----
 pubspec.yaml                 |  2 +-
 test/custom_syntax_test.dart | 51 ++++++++++++++++++++++++++++++++++++
 4 files changed, 67 insertions(+), 6 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index ccb1127..e366034 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,3 +1,11 @@
+## 1.0.9
+
+* Fixed custom inline `builders` (e.g. `a`) duplicating trailing text when the element had multiple children, such as link text containing a `_` or `*` delimiter that the parser splits into separate text nodes (#132)
+
+**Thanks to our contributors:**
+* [@Jess-Gabia](https://github.com/Jess-Gabia) for reporting the issue and identifying the fix (#132)
+* [@amungi](https://github.com/amungi) for confirming the fix in production
+
 ## 1.0.8
 
 * Fixed custom `builders` and `paddingBuilders` for the `hr` tag being ignored
diff --git a/lib/src/builder.dart b/lib/src/builder.dart
index 4f75a5f..ce1bdc4 100644
--- a/lib/src/builder.dart
+++ b/lib/src/builder.dart
@@ -504,11 +504,13 @@ class MarkdownBuilder implements md.NodeVisitor {
           parent.style,
         );
         if (child != null) {
-          if (current.children.isEmpty) {
-            current.children.add(child);
-          } else {
-            current.children[0] = child;
-          }
+          // The returned widget represents the entire element, so discard all
+          // existing inline children — replacing only children[0] leaves any
+          // siblings (e.g. link text split on a `_`/`*` delimiter) to leak
+          // through to the parent and render twice. See issue #132.
+          current.children
+            ..clear()
+            ..add(child);
         }
       } else if (tag == 'img') {
         // create an image widget for this image
diff --git a/pubspec.yaml b/pubspec.yaml
index 60ef218..26db666 100644
--- a/pubspec.yaml
+++ b/pubspec.yaml
@@ -5,7 +5,7 @@ description: A Markdown renderer for Flutter. Create rich text output,
 repository: https://github.com/foresightmobile/flutter_markdown_plus
 issue_tracker: https://github.com/foresightmobile/flutter_markdown_plus/issues
 documentation: https://github.com/foresightmobile/flutter_markdown_plus#readme
-version: 1.0.8
+version: 1.0.9
 
 environment:
   sdk: ^3.4.0
diff --git a/test/custom_syntax_test.dart b/test/custom_syntax_test.dart
index 3e7974b..cc3db27 100644
--- a/test/custom_syntax_test.dart
+++ b/test/custom_syntax_test.dart
@@ -211,6 +211,48 @@ void defineTests() {
       expect(textWidget.data, 'foo');
     },
   );
+
+  testWidgets(
+    'inline builder replaces all children, not just the first (issue #132)',
+    (WidgetTester tester) async {
+      // The link text starts with an unpaired `_`, which the parser splits into
+      // multiple text nodes (`[Text("_"), Text("hello world")]`). A custom `a`
+      // builder returning a widget must replace *all* of them, otherwise the
+      // trailing "hello world" leaks through and renders twice.
+      await tester.pumpWidget(
+        boilerplate(
+          Markdown(
+            data: '[_hello world](https://example.com)',
+            builders: <String, MarkdownElementBuilder>{
+              'a': LinkTagBuilder(),
+            },
+          ),
+        ),
+      );
+
+      expect(find.text('LINK'), findsOneWidget);
+      expect(find.textContaining('hello world', findRichText: true), findsNothing);
+    },
+  );
+
+  testWidgets(
+    'inline builder replaces all children with a `*` delimiter (issue #132)',
+    (WidgetTester tester) async {
+      await tester.pumpWidget(
+        boilerplate(
+          Markdown(
+            data: '[*hello world](https://example.com)',
+            builders: <String, MarkdownElementBuilder>{
+              'a': LinkTagBuilder(),
+            },
+          ),
+        ),
+      );
+
+      expect(find.text('LINK'), findsOneWidget);
+      expect(find.textContaining('hello world', findRichText: true), findsNothing);
+    },
+  );
 }
 
 class SubscriptSyntax extends md.InlineSyntax {
@@ -371,6 +413,15 @@ class ImgBuilder extends MarkdownElementBuilder {
   }
 }
 
+class LinkTagBuilder extends MarkdownElementBuilder {
+  @override
+  Widget visitElementAfter(md.Element element, TextStyle? preferredStyle) {
+    // Deliberately returns a marker that does not contain the link text, so a
+    // test can assert the original children were fully replaced.
+    return const Text('LINK');
+  }
+}
+
 class NoteBuilder extends MarkdownElementBuilder {
   @override
   Widget? visitText(md.Text text, TextStyle? preferredStyle) {