fix(markdown): never parse to an empty document (fixes setContent crash)

.changeset/fix-markdown-empty-doc-fallback.md

@@ -0,0 +1,5 @@
+---
+"@tiptap/markdown": patch
+---
+
+Fix `MarkdownManager.parse()` returning a document with empty `content` for markdown that yields no renderable blocks — whitespace-only input, or input whose only token has no registered handler (e.g. a leading-whitespace-indented line parsed as a code block when no code-block extension is present). A `doc` node requires at least one block child, so the empty document made `setContent` throw `RangeError: Invalid content for node doc: <>`. `parse()` now falls back to a single empty paragraph in that case, matching how an empty markdown string is represented.

packages/markdown/__tests__/empty-doc-fallback.spec.ts

@@ -0,0 +1,48 @@
+import { Editor } from '@tiptap/core'
+import { Document } from '@tiptap/extension-document'
+import { Paragraph } from '@tiptap/extension-paragraph'
+import { Text } from '@tiptap/extension-text'
+import { Markdown, MarkdownManager } from '@tiptap/markdown'
+import { afterEach, describe, expect, it } from 'vitest'
+
+/**
+ * Regression tests for #7914.
+ *
+ * A `doc` node requires at least one block child, so markdown that yields no
+ * renderable blocks must not parse to a doc with empty content — that makes
+ * `setContent` throw `RangeError: Invalid content for node doc: <>`.
+ */
+describe('markdown parse never yields an empty document (#7914)', () => {
+  let editor: Editor | undefined
+  afterEach(() => editor?.destroy())
+
+  const mm = new MarkdownManager({ extensions: [Document, Paragraph, Text] })
+
+  it.each([['           /               '], ['               \\'], ['   '], ['']])(
+    'parse(%j) returns a valid doc with at least one block',
+    input => {
+      const json = mm.parse(input)
+      expect(json.type).toBe('doc')
+      expect(json.content!.length).toBeGreaterThanOrEqual(1)
+      expect(json.content![0].type).toBe('paragraph')
+    },
+  )
+
+  it('setContent with whitespace+slash markdown does not throw', () => {
+    expect(() => {
+      editor = new Editor({
+        extensions: [Document, Paragraph, Text, Markdown],
+        content: '           /               ',
+        contentType: 'markdown',
+      })
+    }).not.toThrow()
+    expect(editor!.getJSON().content![0].type).toBe('paragraph')
+  })
+
+  it('still parses meaningful single-character content', () => {
+    expect(mm.parse('/')).toMatchObject({
+      type: 'doc',
+      content: [{ type: 'paragraph', content: [{ type: 'text', text: '/' }] }],
+    })
+  })
+})

packages/markdown/src/MarkdownManager.ts

@@ -348,10 +348,17 @@ export class MarkdownManager {
       // Convert tokens to Tiptap JSON
       const content = this.parseTokens(tokens, true)
 
-      // Return a document node containing the parsed content
+      // A `doc` node requires at least one block child (`block+`), so an empty
+      // `content` array produces an invalid document that makes `setContent`
+      // throw `RangeError: Invalid content for node doc: <>`. This happens for
+      // input that yields no renderable blocks — whitespace-only markdown, or
+      // markdown whose only token has no registered handler (e.g. an indented
+      // code block when no code-block extension is present, as with a line of
+      // leading whitespace followed by text). Fall back to a single empty
+      // paragraph, matching how an empty markdown string is represented.
       return {
         type: 'doc',
-        content,
+        content: content.length > 0 ? content : [{ type: 'paragraph' }],
       }
     } finally {
       this.activeParseLexer = previousParseLexer