[Bug][preset-commonmark] Unable to use non-paragraph elements as the first element inside a list item

[gudzpoz]

Initial checklist

• I agree to follow the code of conduct
• I searched issues and discussions and couldn’t find anything (or linked relevant results below)

Affected packages and versions

@milkdown/preset-commonmark@^7.3.0

Link to runnable example

No response

Steps to reproduce

Open Milkdown playground.

From Markdown

1. Try Example 293 in the CommonMark Spec:

   > 1. > Blockquote
   > continued here.

2. Observe that an empty paragraph is automatically inserted upon modification.

From Milkdown Editor

1. Focus the editor and type in the following:

   1. > text

2. Observe that one cannot use codeblocks as the first element inside a list item.

Expected behavior

One should be able to use non-paragraph elements as the first element inside a list item, since the Commonmark spec does not pose a limit on it if I understand correctly.

Actually, after applying a simple patch to preset-commonmark, the widget still seems to work fine. Are there other considerations behind this restriction?

--- a/src/node/list-item.ts
+++ b/src/node/list-item.ts
@@ -18,7 +18,7 @@ withMeta(listItemAttr, {
 /// Schema for list item node.
 export const listItemSchema = $nodeSchema('list_item', ctx => ({
   group: 'listItem',
-  content: 'paragraph block*',
+  content: 'block+',
   attrs: {
     label: {
       default: '•',

Actual behavior

As seems to be specified here:

milkdown/packages/preset-commonmark/src/node/list-item.ts

Line 21 in 2a99183

content: 'paragraph block*',

Milkdown requires the first element inside a list item to be a paragraph.

Runtime

Firefox

OS

Linux

Build and bundle tools

Vite