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/extension-table/__tests__/tableMarkdown.spec.ts

@@ -1,6 +1,7 @@
 import { Code } from '@tiptap/extension-code'
 import Document from '@tiptap/extension-document'
 import HardBreak from '@tiptap/extension-hard-break'
+import Heading from '@tiptap/extension-heading'
 import Paragraph from '@tiptap/extension-paragraph'
 import { TableKit } from '@tiptap/extension-table'
 import Text from '@tiptap/extension-text'
@@ -103,7 +104,7 @@
     const markdown = '`a | b`\n---'
     const parsed = manager.parse(markdown)
     const block = parsed.content?.[0]
     expect(block?.type).toBe('heading')
     // The pipe must be preserved verbatim inside the code span.
     const codeNode = block?.content?.find((n: any) => n.marks?.some((m: any) => m.type === 'code'))
     expect(codeNode?.text).toBe('a | b')
@@ -148,7 +149,7 @@
 
 describe('table markdown alignment', () => {
   const markdownManager = new MarkdownManager({
-    extensions: [Document, Paragraph, Text, TableKit],
+    extensions: [Document, Heading, Paragraph, Text, TableKit],
   })
 
   it('should parse and serialize left/right/center table alignment', () => {

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

@@ -0,0 +1,142 @@
+import { Editor, Extension, Node } 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'
+
+// A custom extension whose markdown handler returns a bare top-level text
+// node instead of wrapping it in a block. Simulates a third-party extension
+// misbehaving, to prove the doc-validity fallback doesn't just check
+// `content.length > 0`.
+const BareTextBlock = Extension.create({
+  name: 'bareTextBlock',
+  markdownTokenName: 'bareTextBlock',
+  parseMarkdown: token => ({ type: 'text', text: token.text || '' }),
+  markdownTokenizer: {
+    name: 'bareTextBlock',
+    level: 'block',
+    start: ':::bare',
+    tokenize: (src: string) => {
+      const match = src.match(/^:::bare\s+(.+?)\s+:::/)
+      if (!match) {
+        return undefined
+      }
+      return { type: 'bareTextBlock', raw: match[0], text: match[1] }
+    },
+  },
+})
+
+// A real block node, registered via `registerExtension()` after construction
+// rather than passed to the constructor. Proves the block-node cache reads
+// `this.extensions` (every extension ever registered) and not just
+// `this.baseExtensions` (only the constructor's initial list).
+const DirectlyRegisteredCallout = Node.create({
+  name: 'callout',
+  group: 'block',
+  content: 'text*',
+  markdownTokenName: 'callout',
+  parseMarkdown: (token, helpers) => ({
+    type: 'callout',
+    content: helpers.parseInline(token.tokens || []),
+  }),
+  markdownTokenizer: {
+    name: 'callout',
+    level: 'block',
+    start: ':::callout',
+    tokenize: (src: string, _tokens: unknown, lexer: any) => {
+      const match = src.match(/^:::callout\s+(.+?)\s+:::/)
+      if (!match) {
+        return undefined
+      }
+      return {
+        type: 'callout',
+        raw: match[0],
+        text: match[1],
+        tokens: lexer.inlineTokens(match[1]),
+      }
+    },
+  },
+})
+
+/**
+ * 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('editor.commands.setContent with whitespace+slash markdown does not throw', () => {
+    editor = new Editor({ extensions: [Document, Paragraph, Text, Markdown] })
+
+    expect(() => {
+      editor!.commands.setContent('           /               ', { 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: '/' }] }],
+    })
+  })
+
+  it('falls back to a paragraph when a custom handler yields a bare top-level text node', () => {
+    const bareTextManager = new MarkdownManager({
+      extensions: [Document, Paragraph, Text, BareTextBlock],
+    })
+    const json = bareTextManager.parse(':::bare hello :::')
+
+    expect(json.type).toBe('doc')
+    expect(json.content!.length).toBeGreaterThanOrEqual(1)
+    expect(json.content![0].type).toBe('paragraph')
+  })
+
+  it('setContent does not throw when a custom handler yields a bare top-level text node', () => {
+    expect(() => {
+      editor = new Editor({
+        extensions: [Document, Paragraph, Text, Markdown, BareTextBlock],
+        content: ':::bare hello :::',
+        contentType: 'markdown',
+      })
+    }).not.toThrow()
+    expect(editor!.getJSON().content![0].type).toBe('paragraph')
+  })
+
+  it('recognizes a block extension registered directly via registerExtension, not just the constructor', () => {
+    const directManager = new MarkdownManager({ extensions: [Document, Paragraph, Text] })
+    directManager.registerExtension(DirectlyRegisteredCallout)
+
+    const json = directManager.parse(':::callout hello :::')
+
+    expect(json.content![0].type).toBe('callout')
+  })
+})

packages/markdown/src/MarkdownManager.ts

@@ -58,6 +58,8 @@ export class MarkdownManager {
   private codeTypes: Set<string> = new Set()
   /** Lazy cache of tag names declared by the registered schema's parseDOM rules. */
   private schemaParseDomTagsCache: Set<string> | null = null
+  /** Lazy cache of node type names the registered schema considers block nodes. */
+  private blockNodeNamesCache: Set<string> | null = null
 
   /**
    * Create a MarkdownManager.
@@ -123,6 +125,7 @@ export class MarkdownManager {
   registerExtension(extension: AnyExtension): void {
     // Keep track of all extensions for HTML parsing
     this.extensions.push(extension)
+    this.blockNodeNamesCache = null
 
     // Track extensions that declare `code: true` so we can skip HTML entity
     // encoding inside code contexts without hardcoding specific type names.
@@ -348,10 +351,17 @@ export class MarkdownManager {
       // Convert tokens to Tiptap JSON
       const content = this.parseTokens(tokens, true)
 
+      // A document requires at least one block child. A non-empty `content`
+      // array isn't sufficient proof of that: a custom token handler can
+      // return a bare inline node (e.g. `{ type: 'text' }`) at the top
+      // level, which would still violate the schema's `block+` requirement.
+      const blockNodeNames = this.getBlockNodeNames()
+      const hasBlockContent = content.some(node => node.type && blockNodeNames.has(node.type))
+
       // Return a document node containing the parsed content
       return {
         type: 'doc',
-        content,
+        content: hasBlockContent ? content : [{ type: 'paragraph' }],
       }
     } finally {
       this.activeParseLexer = previousParseLexer
@@ -1051,6 +1061,38 @@ export class MarkdownManager {
     return tags
   }
 
+  /**
+   * Collect node type names in the `block` group. The result is cached until
+   * the next registration.
+   */
+  private getBlockNodeNames(): Set<string> {
+    if (this.blockNodeNamesCache) {
+      return this.blockNodeNamesCache
+    }
+
+    const names = new Set<string>()
+
+    for (const extension of this.extensions) {
+      if (extension.type !== 'node') {
+        continue
+      }
+
+      const context = {
+        name: extension.name,
+        options: extension.options,
+        storage: extension.storage,
+      }
+      const group = callOrReturn(getExtensionField(extension, 'group', context))
+
+      if (typeof group === 'string' && group.split(' ').includes('block')) {
+        names.add(extension.name)
+      }
+    }
+
+    this.blockNodeNamesCache = names
+    return names
+  }
+
   /**
    * Build a JSONContent that preserves the original HTML markup as literal
    * text. Used when the HTML would otherwise be silently dropped during