Decouple load_rels from load_styles (#158)

Previously load_rels was called from inside load_styles, so when a document
had no word/styles.xml, load_styles raised Errno::ENOENT, was rescued, and
load_rels never ran -- leaving @RELS nil. Any later call to #hyperlinks then
crashed with "undefined method 'xpath' for nil".

load_rels is now called independently from initialize and handles a missing
rels file gracefully, so relationships load regardless of whether styles.xml
is present.

Adds a regression fixture (no_styles_with_hyperlink.docx: a document with a
hyperlink relationship but no styles.xml) and a spec asserting #hyperlinks
works in that case.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: satoryu

lib/docx/document.rb

@@ -40,6 +40,7 @@ def initialize(path_or_io, options = {})
       @document_xml = document.get_input_stream.read
       @doc = Nokogiri::XML(@document_xml)
       load_styles
+      load_rels
       load_headers
       load_footers
       yield(self) if block_given?
@@ -226,18 +227,22 @@ def load_footers
     def load_styles
       @styles_xml = @zip.read('word/styles.xml')
       @styles = Nokogiri::XML(@styles_xml)
-      load_rels
     rescue Errno::ENOENT => e
       warn e.message
       nil
     end
 
+    # Loaded independently of styles so that a document without word/styles.xml
+    # still initializes @rels (see #158).
     def load_rels
       rels_entry = @zip.glob('word/_rels/document*.xml.rels').first
       raise Errno::ENOENT unless rels_entry
 
       @rels_xml = rels_entry.get_input_stream.read
       @rels = Nokogiri::XML(@rels_xml)
+    rescue Errno::ENOENT => e
+      warn e.message
+      nil
     end
 
     #--

spec/docx/document_spec.rb

@@ -612,6 +612,20 @@
     end
   end
 
+  # Regression test for #158: relationships (and therefore hyperlinks) must be
+  # loaded independently of styles, so a document without word/styles.xml does
+  # not leave @rels uninitialized.
+  describe 'reading relationships when styles.xml is missing' do
+    before do
+      @doc = Docx::Document.open(@fixtures_path + '/no_styles_with_hyperlink.docx')
+    end
+
+    it 'still loads hyperlink relationships' do
+      expect { @doc.hyperlinks }.to_not raise_error
+      expect(@doc.hyperlinks).to eq('rId4' => 'http://www.google.com/')
+    end
+  end
+
   describe 'replacing contents' do
     let(:replacement_file_path) { @fixtures_path + '/replacement.png' }
     let(:temp_file_path) { Tempfile.new(['docx_gem', '.docx']).path }