From 7e87d3ac63d0616206d4ffe9ad569842a752680e Mon Sep 17 00:00:00 2001
From: Jonas <jonas@freesources.org>
Date: Wed, 1 Jul 2026 17:16:43 +0200
Subject: [PATCH] fix(HardBreak): render DOM linebreak as soft breaks

Fixes: #8775

prosemirror-model 1.25.4 now conversts newlines into the schema's
linebreakReplacement (our HardBreak), producing spurious `<br>` in
nested bullet lists as we use `preserveWhitspace: true` there..

The commit fixes this by distinguishing HardBreaks: when created as
linebreakReplacement, they become type 'soft', otherwise the old
behaviour is retained.

The added tests are not regression tests for #8775. They ensure that
multi-line list items are preserved in Markdown (which they would not
with `preserveWhitespace: false` in BulletList).

Signed-off-by: Jonas <jonas@freesources.org>
---
 src/nodes/HardBreak.js     | 31 ++++++++++++++++++++++++++-----
 src/tests/markdown.spec.js |  3 +++
 2 files changed, 29 insertions(+), 5 deletions(-)

diff --git a/src/nodes/HardBreak.js b/src/nodes/HardBreak.js
index aee34e042b2..d764067a0e7 100644
--- a/src/nodes/HardBreak.js
+++ b/src/nodes/HardBreak.js
@@ -9,7 +9,7 @@ const HardBreak = TipTapHardBreak.extend({
 	addAttributes() {
 		return {
 			syntax: {
-				default: '  ',
+				default: 'soft',
 				rendered: false,
 				keepOnSplit: true,
 				parseHTML: (el) => el.getAttribute('data-syntax') || '  ',
@@ -17,6 +17,14 @@ const HardBreak = TipTapHardBreak.extend({
 		}
 	},
 
+	renderHTML({ node, HTMLAttributes }) {
+		if (node.attrs.syntax === 'soft') {
+			// Rendered as inline whitespace, not a visible line break
+			return ['span', { ...HTMLAttributes, 'data-soft-break': '' }, ' ']
+		}
+		return ['br', HTMLAttributes]
+	},
+
 	addCommands() {
 		return {
 			...this?.parent(),
@@ -26,7 +34,18 @@ const HardBreak = TipTapHardBreak.extend({
 					if (ctx.state.selection.$from.node(d).type.name === 'heading')
 						return false
 				}
-				return this.parent().setHardBreak()(ctx)
+				// Call upstream setHardBreak, then set syntax property for type 'soft'
+				return ctx.chain()
+					.command(this.parent().setHardBreak())
+					.command(({ tr }) => {
+						const pos = tr.selection.$anchor.pos -1
+						const node = tr.doc.nodeAt(pos)
+						if (node?.type.name === 'hardBreak' && node.attrs.syntax === 'soft') {
+							tr.setNodeMarkup(pos, null, { ...node.attrs, syntax: '  ' })
+						}
+						return true
+					})
+					.run()
 			},
 		}
 	},
@@ -34,11 +53,13 @@ const HardBreak = TipTapHardBreak.extend({
 	toMarkdown(state, node, parent, index) {
 		for (let i = index + 1; i < parent.childCount; i++) {
 			if (parent.child(i).type !== node.type) {
-				if (node.attrs.syntax !== 'html') {
+				if (node.attrs.syntax === 'soft') {
+					state.write('\n')
+				} else if (node.attrs.syntax === 'html') {
+					state.write('<br />')
+				} else {
 					state.write(node.attrs.syntax)
 					if (!parent.child(i).text?.startsWith('\n')) state.write('\n')
-				} else {
-					state.write('<br />')
 				}
 				return
 			}
diff --git a/src/tests/markdown.spec.js b/src/tests/markdown.spec.js
index 357464f9932..46361dfe0d2 100644
--- a/src/tests/markdown.spec.js
+++ b/src/tests/markdown.spec.js
@@ -52,6 +52,9 @@ describe('Markdown though editor', () => {
 		expect(markdownThroughEditor('- foo\n- bar')).toBe('- foo\n- bar')
 		expect(markdownThroughEditor('- foo\n\n- bar')).toBe('- foo\n- bar')
 		expect(markdownThroughEditor('- foo\n\n\n- bar')).toBe('- foo\n- bar')
+		expect(markdownThroughEditor('- foo\n  - bar')).toBe('- foo\n  - bar')
+		expect(markdownThroughEditor('- foo\n  - bar\n- baz')).toBe('- foo\n  - bar\n- baz')
+		expect(markdownThroughEditor('- foo\n  bar\n  baz')).toBe('- foo\n  bar\n  baz')
 	})
 	test('ol', () => {
 		expect(markdownThroughEditor('1. foo\n2. bar')).toBe('1. foo\n2. bar')