Fix list continuation if non-list item between. (#18779)

Fix (list): No longer merge separate lists pasted from Microsoft Office into a single list. Closes #18015

Author: Mati365

packages/ckeditor5-paste-from-office/src/filters/list.ts

@@ -268,8 +268,11 @@ function isListContinuation( currentItem: ListLikeElement ) {
 	const previousSibling = currentItem.element.previousSibling;
 
 	if ( !previousSibling ) {
+		const parent = currentItem.element.parent as ViewElement;
+
 		// If it's a li inside ul or ol like in here: https://github.com/ckeditor/ckeditor5/issues/15964.
-		return isList( currentItem.element.parent as ViewElement );
+		// If the parent has previous sibling, which is not a list, then it is not a continuation.
+		return isList( parent ) && ( !parent.previousSibling || isList( parent.previousSibling ) );
 	}
 
 	// Even with the same id the list does not have to be continuous (#43).

packages/ckeditor5-paste-from-office/tests/_data/list/index.js

@@ -21,6 +21,7 @@ import styledAnchor from './styled-anchor/input.word2016.html';
 import multiBlock from './multi-block/input.word.html';
 import mixedElements from './mixed-elements/input.word.html';
 import multiBlockBlockAfter from './multi-block-block-after/input.word.html';
+import listContinuation from './list-continuation/input.word2016.html';
 
 import simpleNormalized from './simple/normalized.word2016.html';
 import styledNormalized from './styled/normalized.word2016.html';
@@ -39,6 +40,7 @@ import styledAnchorNormalized from './styled-anchor/normalized.word2016.html';
 import multiBlockNormalized from './multi-block/normalized.word.html';
 import mixedElementsNormalized from './mixed-elements/normalized.word.html';
 import multiBlockBlockAfterNormalized from './multi-block-block-after/normalized.word.html';
+import listContinuationNormalized from './list-continuation/normalized.word2016.html';
 
 import simpleModel from './simple/model.word2016.html';
 import styledModel from './styled/model.word2016.html';
@@ -57,6 +59,7 @@ import styledAnchorModel from './styled-anchor/model.word2016.html';
 import multiBlockModel from './multi-block/model.word.html';
 import mixedElementsModel from './mixed-elements/model.word.html';
 import multiBlockBlockAfterModel from './multi-block-block-after/model.word.html';
+import listContinuationModel from './list-continuation/model.word2016.html';
 
 export const fixtures = {
 	input: {
@@ -76,7 +79,8 @@ export const fixtures = {
 		styledAnchor,
 		multiBlock,
 		mixedElements,
-		multiBlockBlockAfter
+		multiBlockBlockAfter,
+		listContinuation
 	},
 	normalized: {
 		simple: simpleNormalized,
@@ -95,7 +99,8 @@ export const fixtures = {
 		styledAnchor: styledAnchorNormalized,
 		multiBlock: multiBlockNormalized,
 		mixedElements: mixedElementsNormalized,
-		multiBlockBlockAfter: multiBlockBlockAfterNormalized
+		multiBlockBlockAfter: multiBlockBlockAfterNormalized,
+		listContinuation: listContinuationNormalized
 	},
 	model: {
 		simple: simpleModel,
@@ -114,7 +119,8 @@ export const fixtures = {
 		styledAnchor: styledAnchorModel,
 		multiBlock: multiBlockModel,
 		mixedElements: mixedElementsModel,
-		multiBlockBlockAfter: multiBlockBlockAfterModel
+		multiBlockBlockAfter: multiBlockBlockAfterModel,
+		listContinuation: listContinuationModel
 	}
 };