From fd5cd9398db1a9d3cdd8a5e4e084b2c9c25fe114 Mon Sep 17 00:00:00 2001
From: Qiu shao <504250439@Qq.com>
Date: Tue, 18 Aug 2026 09:59:35 +0000
Subject: [PATCH] Fix markdown task list marker lookup (#60646)
# Objective
Fix Markdown preview task list checkboxes not rendering for task items
in
loose or nested lists.
For example, this Markdown should render all three items with
checkboxes:
```markdown
- [ ] test
- [x] test
- [x] test
```
Before this change, the items after blank lines could fall back to ordinary
list bullets instead of task checkboxes.
## Solution
Update Markdown list item rendering to detect task list markers in both tight
and loose list event shapes emitted by pulldown-cmark.
The previous renderer only handled:
Item -> TaskListMarker
Loose lists can emit:
Item -> Paragraph -> TaskListMarker
This PR adds a small helper to find task markers for both forms, then reuses
the existing checkbox rendering and toggle behavior.
## Testing
Tested on macOS with:
rustup run 1.95.0 cargo test -p markdown
test_task_marker_lookup_handles_loose_and_nested_lists
rustup run 1.95.0 cargo test -p markdown test_table_checkbox
The first test covers loose and nested task list items. The table checkbox
tests verify that [x] and [ ] inside tables still remain text and are not
treated as task list checkboxes.
## Self-Review Checklist:
- [x] I've reviewed my own diff for quality, security, and reliability
- [x] Unsafe blocks (if any) have justifying comments
- [x] The content adheres to Zed's UI standards ([UX/UI](https://github.com/zed-industries/zed/blob/main/CONTRIBUTING.md#uiux-checklist) and [icon](https://github.com/zed-industries/zed/blob/main/crates/icons/README.md) guidelines)
- [x] Tests cover the new/changed behavior
- [x] Performance impact has been considered and is acceptable
## Showcase
before
after
---
Release Notes:
- Fixed Markdown Preview for loose list item markers
---------
Co-authored-by: dino
---
crates/markdown/src/markdown.rs | 126 ++++++++++++++++++++++----------
1 file changed, 88 insertions(+), 38 deletions(-)
diff --git a/crates/markdown/src/markdown.rs b/crates/markdown/src/markdown.rs
index 7f556351428..43189be5fd7 100644
--- a/crates/markdown/src/markdown.rs
+++ b/crates/markdown/src/markdown.rs
@@ -2636,44 +2636,36 @@ impl Element for MarkdownElement {
builder.push_div(div().pl_2p5(), range, markdown_end);
}
MarkdownTag::Item => {
- let bullet =
- if let Some((task_range, MarkdownEvent::TaskListMarker(checked))) =
- parsed_markdown.events.get(index.saturating_add(1))
- {
- let source = &parsed_markdown.source()[range.clone()];
- let checked = *checked;
- let toggle_state = if checked {
- ToggleState::Selected
- } else {
- ToggleState::Unselected
- };
+ let bullet = if let Some((task_range, checked)) =
+ task_list_marker_for_item(&parsed_markdown.events, index)
+ {
+ let source = &parsed_markdown.source()[range.clone()];
+ let checkbox = Checkbox::new(
+ ElementId::Name(source.to_string().into()),
+ ToggleState::from(checked),
+ )
+ .fill();
- let checkbox = Checkbox::new(
- ElementId::Name(source.to_string().into()),
- toggle_state,
- )
- .fill();
-
- if let Some(on_toggle) = self.on_checkbox_toggle.clone() {
- let task_source_range = task_range.clone();
- checkbox
- .on_click(move |_state, window, cx| {
- on_toggle(
- task_source_range.clone(),
- !checked,
- window,
- cx,
- );
- })
- .into_any_element()
- } else {
- checkbox.visualization_only(true).into_any_element()
- }
- } else if let Some(bullet_index) = builder.next_bullet_index() {
- div().child(format!("{}.", bullet_index)).into_any_element()
+ if let Some(on_toggle) = self.on_checkbox_toggle.clone() {
+ let task_source_range = task_range.clone();
+ checkbox
+ .on_click(move |_state, window, cx| {
+ on_toggle(
+ task_source_range.clone(),
+ !checked,
+ window,
+ cx,
+ );
+ })
+ .into_any_element()
} else {
- div().child("•").into_any_element()
- };
+ checkbox.visualization_only(true).into_any_element()
+ }
+ } else if let Some(bullet_index) = builder.next_bullet_index() {
+ div().child(format!("{}.", bullet_index)).into_any_element()
+ } else {
+ div().child("•").into_any_element()
+ };
self.push_markdown_list_item(&mut builder, bullet, range, markdown_end);
}
MarkdownTag::Emphasis => builder.push_text_style(TextStyleRefinement {
@@ -3414,6 +3406,25 @@ fn alignment_to_text_align(alignment: Alignment) -> Option {
}
}
+// The contents of loose list items are wrapped in a paragraph, so their task
+// marker follows `Start(Paragraph)` rather than `Start(Item)`.
+fn task_list_marker_for_item(
+ events: &[(Range, MarkdownEvent)],
+ item_index: usize,
+) -> Option<(Range, bool)> {
+ let next_index = item_index.checked_add(1)?;
+ let marker_index = match &events.get(next_index)?.1 {
+ MarkdownEvent::Start(MarkdownTag::Paragraph) => next_index.checked_add(1)?,
+ MarkdownEvent::TaskListMarker(_) => next_index,
+ _ => return None,
+ };
+
+ match events.get(marker_index)? {
+ (range, MarkdownEvent::TaskListMarker(checked)) => Some((range.clone(), *checked)),
+ _ => None,
+ }
+}
+
struct MetadataCellStyle {
row_index: usize,
is_key: bool,
@@ -5414,10 +5425,49 @@ mod tests {
assert_eq!(table.current_cell_alignment(), None);
}
+ #[test]
+ fn test_task_list_marker_for_item() {
+ // Small helper that takes the Markdown contents and returns a vector of
+ // all task list marker strings as well as whether they are checked or
+ // not.
+ let task_marker_states = |markdown: &str| -> Vec<(String, bool)> {
+ let events = parse_markdown_with_options(markdown, false, false, false).events;
+
+ events
+ .iter()
+ .enumerate()
+ .filter_map(|(index, (_, event))| {
+ matches!(event, MarkdownEvent::Start(MarkdownTag::Item))
+ .then(|| task_list_marker_for_item(&events, index))
+ .flatten()
+ })
+ .map(|(range, checked)| (markdown[range].to_string(), checked))
+ .collect::>()
+ };
+
+ assert_eq!(
+ task_marker_states("- [ ] task"),
+ vec![("[ ]".to_string(), false)]
+ );
+ assert_eq!(
+ task_marker_states("- [x] first\n\n- [ ] second"),
+ vec![("[x]".to_string(), true), ("[ ]".to_string(), false)]
+ );
+ assert_eq!(
+ task_marker_states("- [ ] top task\n\n- [x] done task\n\n - [x] nested done\n"),
+ vec![
+ ("[ ]".to_string(), false),
+ ("[x]".to_string(), true),
+ ("[x]".to_string(), true)
+ ]
+ );
+ assert_eq!(task_marker_states("- ordinary item"), vec![]);
+ }
+
#[test]
fn test_table_checkbox_detection() {
let md = "| Done |\n|------|\n| [x] |\n| [ ] |";
- let events = crate::parser::parse_markdown_with_options(md, false, false, false).events;
+ let events = parse_markdown_with_options(md, false, false, false).events;
let mut in_table = false;
let mut cell_texts: Vec = Vec::new();
@@ -5459,7 +5509,7 @@ mod tests {
#[test]
fn test_table_checkbox_marker_source_range() {
let md = "| Done |\n|------|\n| [x] |\n| [ ] |";
- let events = crate::parser::parse_markdown_with_options(md, false, false, false).events;
+ let events = parse_markdown_with_options(md, false, false, false).events;
let mut in_cell = false;
let mut pending_text = String::new();