resolves asciidoctor#4468 treat bare URL enclosed in angle brackets a…

…s unconstrained syntax

CHANGELOG.adoc

@@ -79,6 +79,7 @@ Bug Fixes::
   * Move abstract inside info tag in DocBook output (#3602)
   * Honor secondary and tertiary terms on `indexterm` macro when primary term is quoted and contains an equals sign (#3652)
   * Remove extra border below doctitle when sidebar toc is collapsed into main content area (#4523)
+  * Treat bare URL enclosed in angle brackets as unconstrained syntax (#4468)
 
 == 2.0.20 (2023-05-18) - @mojavelinux
 

lib/asciidoctor/substitutors.rb

@@ -545,19 +545,29 @@ def sub_macros text
           prefix = '' if prefix == 'link:'
           link_text = nil if (link_text = $4).empty?
         else
+          tail = $6
+          case prefix
           # invalid macro syntax (link: prefix w/o trailing square brackets or enclosed in double quotes)
           # FIXME we probably shouldn't even get here when the link: prefix is present; the regex is doing too much
-          case prefix
           when 'link:', ?", ?'
             next $&
+          when '<'
+            if tail == ';' ? (target.end_with? '>') : (gt_idx = target.index '>')
+              # drop surrounding <> from URL
+              prefix = ''
+              tail = nil
+              if gt_idx
+                suffix = target.slice (gt_idx + 4)
+                target = target.slice 0, gt_idx
+              else
+                target = target.slice 0, target.length - 4
+              end
+              next $& if target.end_with? '://'
+            end
           end
-          case $6
+          case tail
           when ';'
-            if prefix == '&lt;' && (target.end_with? '&gt;')
-              # move surrounding <> out of URL
-              prefix = ''
-              target = target.slice 0, target.length - 4
-            elsif (target = target.chop).end_with? ')'
+            if (target = target.chop).end_with? ')'
               # move trailing ); out of URL
               target = target.chop
               suffix = ');'

test/links_test.rb

@@ -81,6 +81,10 @@
     assert_xpath '//a[@href="http://asciidoc.org"][text()="http://asciidoc.org"]', convert_string('<http://asciidoc.org> is the project page for AsciiDoc.'), 1
   end
 
+  test 'qualified url surrounded by angled brackets in unconstrained context' do
+    assert_xpath '//a[@href="http://asciidoc.org"][text()="http://asciidoc.org"]', convert_string('URLは<http://asciidoc.org>。'), 1
+  end
+
   test 'qualified url surrounded by round brackets' do
     assert_xpath '//a[@href="http://asciidoc.org"][text()="http://asciidoc.org"]', convert_string('(http://asciidoc.org) is the project page for AsciiDoc.'), 1
   end