resolves #472 fix crash when section title contains inline anchor

CHANGELOG.adoc

@@ -5,6 +5,10 @@
 This document provides a high-level view of the changes to the {project-name} by release.
 For a detailed view of what has changed, refer to the {uri-repo}/commits/master[commit history] on GitHub.
 
+== Unreleased
+
+* fix crash when section title contains inline anchor (#472)
+
 == 2.1.0 (2024-02-04) - @slonopotamus
 
 * drop MOBI support

lib/asciidoctor-epub3/converter.rb

@@ -95,6 +95,11 @@ def write(output, target)
 
       def initialize(backend, opts = {})
         super
+
+        @xrefs_seen = Set.new
+        @media_files = {}
+        @footnotes = []
+
         basebackend 'html'
         outfilesuffix '.epub'
         htmlsyntax 'xml'
@@ -149,9 +154,6 @@ def convert_document(node)
         @extract = node.attr? 'ebook-extract'
         @compress = node.attr 'ebook-compress'
         @epubcheck_path = node.attr 'ebook-epubcheck-path'
-        @xrefs_seen = ::Set.new
-        @media_files = {}
-        @footnotes = []
 
         @book = GEPUB::Book.new 'EPUB/package.opf'
         @book.epub_backward_compat = true

spec/converter_spec.rb

@@ -277,6 +277,20 @@
       expect(book).not_to be_nil
     end
 
+    # Test for https://github.com/asciidoctor/asciidoctor-epub3/issues/472
+    it 'does not crash when sees inline anchor' do
+      book = to_epub <<~EOS
+        = Test
+        :doctype: book
+
+        [[chapter-1]]
+        == Chapter 1
+
+        == <<chapter-1>> Chapter 2
+      EOS
+      expect(book).not_to be_nil
+    end
+
     it 'supports video' do
       book, = to_epub fixture_file('video/book.adoc')
       chapter = book.item_by_href '_chapter.xhtml'