Merge pull request #3780 from nextcloud/backport/3766/stable25

[stable25] fix: empty code blocks

src/nodes/CodeBlock.js

@@ -2,14 +2,19 @@ import TiptapCodeBlock from '@tiptap/extension-code-block'
 import { defaultMarkdownSerializer } from 'prosemirror-markdown'
 
 const CodeBlock = TiptapCodeBlock.extend({
+
 	parseHTML() {
 		return [
 			{
 				tag: 'pre',
 				preserveWhitespace: 'full',
-				// Remove trailing newline from code blocks (Github issue #2344)
+				// Remove trailing newline from code blocks (#2344)
 				getContent: (node, schema) => {
-					return schema.nodes.codeBlock.create(null, [schema.text(node.textContent.replace(/\n$/, ''))])
+					const textContent = node.textContent.replace(/\n$/, '')
+					const inner = textContent
+						? [schema.text(textContent)]
+						: []
+					return schema.nodes.codeBlock.create(null, inner)
 				},
 			},
 		]

src/tests/markdown.spec.js

@@ -134,6 +134,8 @@ describe('Markdown though editor', () => {
 		expect(markdownThroughEditor('```\n<?php echo "Hello World";\n```')).toBe('```\n<?php echo "Hello World";\n```')
 		// Issue #3328
 		expect(markdownThroughEditor('```python\nprint("Hello World")\n```')).toBe('```python\nprint("Hello World")\n```')
+		// Issue #3739
+		expect(markdownThroughEditor('```\n```')).toBe('```\n```')
 	})
 	test('markdown untouched', () => {
 		// Issue #2703