From 4b7682c8a8616bcf2fbaa408ae3bfb3c336bda7c Mon Sep 17 00:00:00 2001
From: Kuba Niegowski <j.niegowski@cksource.com>
Date: Fri, 28 Jun 2024 16:22:09 +0200
Subject: [PATCH 1/2] List upcast converters should not remove invalid nodes.

---
 .../ckeditor5-list/src/list/converters.ts     | 23 -------
 .../ckeditor5-list/src/list/listediting.ts    |  3 -
 .../list/converters-data-single-block.js      | 61 ++++++++++-------
 .../tests/list/converters-data.js             | 67 +++++++++++++------
 4 files changed, 83 insertions(+), 71 deletions(-)

diff --git a/packages/ckeditor5-list/src/list/converters.ts b/packages/ckeditor5-list/src/list/converters.ts
index 102130e6585..1922058f701 100644
--- a/packages/ckeditor5-list/src/list/converters.ts
+++ b/packages/ckeditor5-list/src/list/converters.ts
@@ -120,29 +120,6 @@ export function listItemUpcastConverter(): GetCallback<UpcastElementEvent> {
 	};
 }
 
-/**
- * Returns the upcast converter for the `<ul>` and `<ol>` view elements that cleans the input view of garbage.
- * This is mostly to clean whitespaces from between the `<li>` view elements inside the view list element. However,
- * incorrect data can also be cleared if the view was incorrect.
- *
- * @internal
- */
-export function listUpcastCleanList(): GetCallback<UpcastElementEvent> {
-	return ( evt, data, conversionApi ) => {
-		if ( !conversionApi.consumable.test( data.viewItem, { name: true } ) ) {
-			return;
-		}
-
-		const viewWriter = new UpcastWriter( data.viewItem.document );
-
-		for ( const child of Array.from( data.viewItem.getChildren() ) ) {
-			if ( !isListItemView( child ) && !isListView( child ) ) {
-				viewWriter.remove( child );
-			}
-		}
-	};
-}
-
 /**
  * Returns a model document change:data event listener that triggers conversion of related items if needed.
  *
diff --git a/packages/ckeditor5-list/src/list/listediting.ts b/packages/ckeditor5-list/src/list/listediting.ts
index 593cac7102a..21ac344f211 100644
--- a/packages/ckeditor5-list/src/list/listediting.ts
+++ b/packages/ckeditor5-list/src/list/listediting.ts
@@ -45,7 +45,6 @@ import {
 	listItemDowncastConverter,
 	listItemDowncastRemoveConverter,
 	listItemUpcastConverter,
-	listUpcastCleanList,
 	reconvertItemsOnDataChange
 } from './converters.js';
 import {
@@ -456,8 +455,6 @@ export default class ListEditing extends Plugin {
 			} )
 			.add( dispatcher => {
 				dispatcher.on<UpcastElementEvent>( 'element:li', listItemUpcastConverter() );
-				dispatcher.on<UpcastElementEvent>( 'element:ul', listUpcastCleanList(), { priority: 'high' } );
-				dispatcher.on<UpcastElementEvent>( 'element:ol', listUpcastCleanList(), { priority: 'high' } );
 			} );
 
 		if ( !multiBlock ) {
diff --git a/packages/ckeditor5-list/tests/list/converters-data-single-block.js b/packages/ckeditor5-list/tests/list/converters-data-single-block.js
index 7105b4261de..e935ecfa57a 100644
--- a/packages/ckeditor5-list/tests/list/converters-data-single-block.js
+++ b/packages/ckeditor5-list/tests/list/converters-data-single-block.js
@@ -238,7 +238,8 @@ describe( 'ListEditing (multiBlock=false) - converters - data pipeline', () => {
 			);
 		} );
 
-		it( 'clears incorrect elements', () => {
+		// See https://github.com/ckeditor/ckeditor5/issues/16450.
+		it( 'does not clear incorrect elements', () => {
 			test.data(
 				'<ul>' +
 					'x' +
@@ -249,14 +250,20 @@ describe( 'ListEditing (multiBlock=false) - converters - data pipeline', () => {
 				'</ul>' +
 				'<p>c</p>',
 
+				'<paragraph>x</paragraph>' +
 				'<listItem listIndent="0" listItemId="a00" listType="bulleted">a</listItem>' +
 				'<listItem listIndent="0" listItemId="a01" listType="bulleted">b</listItem>' +
+				'<paragraph>xxx</paragraph>' +
+				'<paragraph>x</paragraph>' +
 				'<paragraph>c</paragraph>',
 
+				'<p>x</p>' +
 				'<ul>' +
 					'<li>a</li>' +
 					'<li>b</li>' +
 				'</ul>' +
+				'<p>xxx</p>' +
+				'<p>x</p>' +
 				'<p>c</p>'
 			);
 		} );
@@ -1540,6 +1547,7 @@ describe( 'ListEditing (multiBlock=false) - converters - data pipeline', () => {
 			);
 		} );
 
+		// See https://github.com/ckeditor/ckeditor5/issues/16450.
 		it( 'mixed lists deep structure, white spaces, incorrect content, empty items', () => {
 			test.data(
 				'<p>foo</p>' +
@@ -1586,7 +1594,8 @@ describe( 'ListEditing (multiBlock=false) - converters - data pipeline', () => {
 				'<p>bar</p>',
 
 				'<paragraph>foo</paragraph>' +
-				'<listItem listIndent="0" listItemId="a07" listType="bulleted">1</listItem>' +
+				'<paragraph>xxx</paragraph>' +
+				'<listItem listIndent="0" listItemId="a07" listType="bulleted">1xxx</listItem>' +
 				'<listItem listIndent="1" listItemId="a04" listType="bulleted"></listItem>' +
 				'<listItem listIndent="2" listItemId="a00" listType="bulleted"></listItem>' +
 				'<listItem listIndent="2" listItemId="a01" listType="bulleted">1.1.2</listItem>' +
@@ -1594,21 +1603,24 @@ describe( 'ListEditing (multiBlock=false) - converters - data pipeline', () => {
 				'<listItem listIndent="2" listItemId="a03" listType="numbered">1.1.4</listItem>' +
 				'<listItem listIndent="1" listItemId="a06" listType="bulleted"></listItem>' +
 				'<listItem listIndent="2" listItemId="a05" listType="bulleted">1.2.1</listItem>' +
-				'<listItem listIndent="0" listItemId="a08" listType="bulleted">2</listItem>' +
-				'<listItem listIndent="0" listItemId="a10" listType="bulleted"></listItem>' +
-				'<listItem listIndent="1" listItemId="a0d" listType="numbered">3<$text bold="true">.</$text>1</listItem>' +
-				'<listItem listIndent="2" listItemId="a0b" listType="bulleted">3.1.1</listItem>' +
-				'<listItem listIndent="3" listItemId="a09" listType="numbered">3.1.1.1</listItem>' +
-				'<listItem listIndent="3" listItemId="a0a" listType="bulleted">3.1.1.2</listItem>' +
-				'<listItem listIndent="2" listItemId="a0c" listType="bulleted">3.1.2</listItem>' +
 				'<listItem listIndent="0" listItemId="a11" listType="bulleted">xxx</listItem>' +
+				'<listItem listIndent="0" listItemId="a08" listType="bulleted">2</listItem>' +
+				'<paragraph>xxx</paragraph>' +
+				'<listItem listIndent="0" listItemId="a0d" listType="numbered">3<$text bold="true">.</$text>1</listItem>' +
+				'<listItem listIndent="1" listItemId="a0b" listType="bulleted">3.1.1</listItem>' +
+				'<listItem listIndent="2" listItemId="a09" listType="numbered">3.1.1.1</listItem>' +
+				'<listItem listIndent="2" listItemId="a0a" listType="bulleted">3.1.1.2</listItem>' +
+				'<listItem listIndent="1" listItemId="a0c" listType="bulleted">3.1.2</listItem>' +
+				'<listItem listIndent="0" listItemId="a10" listType="bulleted">xxx</listItem>' +
 				'<listItem listIndent="1" listItemId="a0e" listType="bulleted">3.2</listItem>' +
 				'<listItem listIndent="1" listItemId="a0f" listType="bulleted">3.3</listItem>' +
+				'<paragraph>xxx</paragraph>' +
 				'<paragraph>bar</paragraph>',
 
 				'<p>foo</p>' +
+				'<p>xxx</p>' +
 				'<ul>' +
-					'<li>1' +
+					'<li>1xxx' +
 						'<ul>' +
 							'<li>&nbsp;' +
 								'<ul>' +
@@ -1627,24 +1639,26 @@ describe( 'ListEditing (multiBlock=false) - converters - data pipeline', () => {
 							'</li>' +
 						'</ul>' +
 					'</li>' +
+					'<li>xxx</li>' +
 					'<li>2</li>' +
-					'<li>&nbsp;' +
-						'<ol>' +
-							'<li>3<strong>.</strong>1' +
+				'</ul>' +
+				'<p>xxx</p>' +
+				'<ol>' +
+					'<li>3<strong>.</strong>1' +
+						'<ul>' +
+							'<li>3.1.1' +
+								'<ol>' +
+									'<li>3.1.1.1</li>' +
+								'</ol>' +
 								'<ul>' +
-									'<li>3.1.1' +
-										'<ol>' +
-											'<li>3.1.1.1</li>' +
-										'</ol>' +
-										'<ul>' +
-											'<li>3.1.1.2</li>' +
-										'</ul>' +
-									'</li>' +
-									'<li>3.1.2</li>' +
+									'<li>3.1.1.2</li>' +
 								'</ul>' +
 							'</li>' +
-						'</ol>' +
+							'<li>3.1.2</li>' +
+						'</ul>' +
 					'</li>' +
+				'</ol>' +
+				'<ul>' +
 					'<li>xxx' +
 						'<ul>' +
 							'<li>3.2</li>' +
@@ -1652,6 +1666,7 @@ describe( 'ListEditing (multiBlock=false) - converters - data pipeline', () => {
 						'</ul>' +
 					'</li>' +
 				'</ul>' +
+				'<p>xxx</p>' +
 				'<p>bar</p>'
 			);
 		} );
diff --git a/packages/ckeditor5-list/tests/list/converters-data.js b/packages/ckeditor5-list/tests/list/converters-data.js
index afcbd387545..049fa08598d 100644
--- a/packages/ckeditor5-list/tests/list/converters-data.js
+++ b/packages/ckeditor5-list/tests/list/converters-data.js
@@ -249,7 +249,8 @@ describe( 'ListEditing - converters - data pipeline', () => {
 			);
 		} );
 
-		it( 'clears incorrect elements', () => {
+		// See https://github.com/ckeditor/ckeditor5/issues/16450.
+		it( 'does not clear incorrect elements (text inside ul/ol should not be removed)', () => {
 			test.data(
 				'<ul>' +
 					'x' +
@@ -260,14 +261,20 @@ describe( 'ListEditing - converters - data pipeline', () => {
 				'</ul>' +
 				'<p>c</p>',
 
+				'<paragraph>x</paragraph>' +
 				'<paragraph listIndent="0" listItemId="a00" listType="bulleted">a</paragraph>' +
 				'<paragraph listIndent="0" listItemId="a01" listType="bulleted">b</paragraph>' +
+				'<paragraph>xxx</paragraph>' +
+				'<paragraph>x</paragraph>' +
 				'<paragraph>c</paragraph>',
 
+				'<p>x</p>' +
 				'<ul>' +
 					'<li>a</li>' +
 					'<li>b</li>' +
 				'</ul>' +
+				'<p>xxx</p>' +
+				'<p>x</p>' +
 				'<p>c</p>'
 			);
 		} );
@@ -2076,6 +2083,7 @@ describe( 'ListEditing - converters - data pipeline', () => {
 			);
 		} );
 
+		// See https://github.com/ckeditor/ckeditor5/issues/16450.
 		it( 'mixed lists deep structure, white spaces, incorrect content, empty items', () => {
 			test.data(
 				'<p>foo</p>' +
@@ -2122,7 +2130,8 @@ describe( 'ListEditing - converters - data pipeline', () => {
 				'<p>bar</p>',
 
 				'<paragraph>foo</paragraph>' +
-				'<paragraph listIndent="0" listItemId="a07" listType="bulleted">1</paragraph>' +
+				'<paragraph>xxx</paragraph>' +
+				'<paragraph listIndent="0" listItemId="a07" listType="bulleted">1xxx</paragraph>' +
 				'<paragraph listIndent="1" listItemId="a04" listType="bulleted"></paragraph>' +
 				'<paragraph listIndent="2" listItemId="a00" listType="bulleted"></paragraph>' +
 				'<paragraph listIndent="2" listItemId="a01" listType="bulleted">1.1.2</paragraph>' +
@@ -2130,11 +2139,10 @@ describe( 'ListEditing - converters - data pipeline', () => {
 				'<paragraph listIndent="2" listItemId="a03" listType="numbered">1.1.4</paragraph>' +
 				'<paragraph listIndent="1" listItemId="a06" listType="bulleted"></paragraph>' +
 				'<paragraph listIndent="2" listItemId="a05" listType="bulleted">1.2.1</paragraph>' +
+				'<paragraph listIndent="0" listItemId="a07" listType="bulleted">xxx</paragraph>' +
 				'<paragraph listIndent="0" listItemId="a08" listType="bulleted">2</paragraph>' +
-				'<paragraph listIndent="0" listItemId="a10" listType="bulleted"></paragraph>' +
-				'<paragraph listIndent="1" listItemId="a0d" listType="numbered">' +
-					'3<$text bold="true">.</$text>1' +
-				'</paragraph>' +
+				'<paragraph listIndent="0" listItemId="a10" listType="bulleted">xxx</paragraph>' +
+				'<paragraph listIndent="1" listItemId="a0d" listType="numbered">3<$text bold="true">.</$text>1</paragraph>' +
 				'<paragraph listIndent="2" listItemId="a0b" listType="bulleted">3.1.1</paragraph>' +
 				'<paragraph listIndent="3" listItemId="a09" listType="numbered">3.1.1.1</paragraph>' +
 				'<paragraph listIndent="3" listItemId="a0a" listType="bulleted">3.1.1.2</paragraph>' +
@@ -2142,44 +2150,59 @@ describe( 'ListEditing - converters - data pipeline', () => {
 				'<paragraph listIndent="0" listItemId="a10" listType="bulleted">xxx</paragraph>' +
 				'<paragraph listIndent="1" listItemId="a0e" listType="bulleted">3.2</paragraph>' +
 				'<paragraph listIndent="1" listItemId="a0f" listType="bulleted">3.3</paragraph>' +
+				'<paragraph>xxx</paragraph>' +
 				'<paragraph>bar</paragraph>',
 
 				'<p>foo</p>' +
+				'<p>xxx</p>' +
 				'<ul>' +
 					'<li>' +
-						'1' +
+						'<p>1xxx</p>' +
 						'<ul>' +
-							'<li>' +
-								'&nbsp;' +
-								'<ul><li>&nbsp;</li><li>1.1.2</li></ul>' +
-								'<ol><li>1.1.3</li><li>1.1.4</li></ol>' +
+							'<li>&nbsp;' +
+								'<ul>' +
+									'<li>&nbsp;</li>' +
+									'<li>1.1.2</li>' +
+								'</ul>' +
+								'<ol>' +
+									'<li>1.1.3</li>' +
+									'<li>1.1.4</li>' +
+								'</ol>' +
 							'</li>' +
-							'<li>' +
-								'&nbsp;' +
-								'<ul><li>1.2.1</li></ul>' +
+							'<li>&nbsp;' +
+								'<ul>' +
+									'<li>1.2.1</li>' +
+								'</ul>' +
 							'</li>' +
 						'</ul>' +
+						'<p>xxx</p>' +
 					'</li>' +
 					'<li>2</li>' +
 					'<li>' +
-						'<p>&nbsp;</p>' +
+						'<p>xxx</p>' +
 						'<ol>' +
-							'<li>' +
-								'3<strong>.</strong>1' +
+							'<li>3<strong>.</strong>1' +
 								'<ul>' +
-									'<li>' +
-										'3.1.1' +
-										'<ol><li>3.1.1.1</li></ol>' +
-										'<ul><li>3.1.1.2</li></ul>' +
+									'<li>3.1.1' +
+										'<ol>' +
+											'<li>3.1.1.1</li>' +
+										'</ol>' +
+										'<ul>' +
+											'<li>3.1.1.2</li>' +
+										'</ul>' +
 									'</li>' +
 									'<li>3.1.2</li>' +
 								'</ul>' +
 							'</li>' +
 						'</ol>' +
 						'<p>xxx</p>' +
-						'<ul><li>3.2</li><li>3.3</li></ul>' +
+						'<ul>' +
+							'<li>3.2</li>' +
+							'<li>3.3</li>' +
+						'</ul>' +
 					'</li>' +
 				'</ul>' +
+				'<p>xxx</p>' +
 				'<p>bar</p>'
 			);
 		} );

From da0f00e0f9b0d6eece6eef01ad5a22e2be9f4119 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Piotrek=20Koszuli=C5=84ski?= <pkoszulinski@gmail.com>
Date: Wed, 3 Jul 2024 09:36:05 +0200
Subject: [PATCH 2/2] Added one more test.

---
 .../list/converters-data-single-block.js      | 48 ++++++++++++++++++-
 1 file changed, 47 insertions(+), 1 deletion(-)

diff --git a/packages/ckeditor5-list/tests/list/converters-data-single-block.js b/packages/ckeditor5-list/tests/list/converters-data-single-block.js
index e935ecfa57a..3162b4a3c3a 100644
--- a/packages/ckeditor5-list/tests/list/converters-data-single-block.js
+++ b/packages/ckeditor5-list/tests/list/converters-data-single-block.js
@@ -239,7 +239,7 @@ describe( 'ListEditing (multiBlock=false) - converters - data pipeline', () => {
 		} );
 
 		// See https://github.com/ckeditor/ckeditor5/issues/16450.
-		it( 'does not clear incorrect elements', () => {
+		it( 'does not clear incorrect nodes within <ul>', () => {
 			test.data(
 				'<ul>' +
 					'x' +
@@ -268,6 +268,52 @@ describe( 'ListEditing (multiBlock=false) - converters - data pipeline', () => {
 			);
 		} );
 
+		// See https://github.com/ckeditor/ckeditor5/issues/16450.
+		it( 'does not clear incorrect nodes and elements within <ul>', () => {
+			test.data(
+				'<p>0</p>' +
+				'<ul>' +
+					'<strong>x</strong>y' +
+					'<li>a</li>' +
+					'<p>z</p>' +
+					'<li>b</li>' +
+					'<p>z1</p>' +
+					'<p>z2</p>' +
+					'<li>c</li>' +
+					'x' +
+				'</ul>' +
+				'<p>1</p>',
+
+				'<paragraph>0</paragraph>' +
+				'<paragraph><$text bold="true">x</$text>y</paragraph>' +
+				'<listItem listIndent="0" listItemId="a00" listType="bulleted">a</listItem>' +
+				'<paragraph>z</paragraph>' +
+				'<listItem listIndent="0" listItemId="a01" listType="bulleted">b</listItem>' +
+				'<paragraph>z1</paragraph>' +
+				'<paragraph>z2</paragraph>' +
+				'<listItem listIndent="0" listItemId="a02" listType="bulleted">c</listItem>' +
+				'<paragraph>x</paragraph>' +
+				'<paragraph>1</paragraph>',
+
+				'<p>0</p>' +
+				'<p><strong>x</strong>y</p>' +
+				'<ul>' +
+					'<li>a</li>' +
+				'</ul>' +
+				'<p>z</p>' +
+				'<ul>' +
+					'<li>b</li>' +
+				'</ul>' +
+				'<p>z1</p>' +
+				'<p>z2</p>' +
+				'<ul>' +
+					'<li>c</li>' +
+				'</ul>' +
+				'<p>x</p>' +
+				'<p>1</p>'
+			);
+		} );
+
 		it( 'clears whitespaces', () => {
 			test.data(
 				'<p>foo</p>' +