don't swallow square brackets when processing escaped URL macro

CHANGELOG.adoc

@@ -75,6 +75,7 @@ Bug Fixes::
   * Manify alt text of block image in manpage output (#4401)
   * Adjust font size of term in horizontal dlist to match font size of term in regular dlist
   * Implicitly attach nested list that starts with block attribute lines to dlist entry (#4268)
+  * Don't swallow square brackets when processing escaped URL macro
 
 == 2.0.18 (2022-10-15) - @mojavelinux
 

lib/asciidoctor/substitutors.rb

@@ -529,7 +529,7 @@ def sub_macros text
       text = text.gsub InlineLinkRx do
         if (target = $2).start_with? RS
           # honor the escape
-          next %(#{$1}#{target.slice 1, target.length}#{$4})
+          next ($&.slice 0, (rs_idx = $1.length)) + ($&.slice rs_idx + 1, $&.length)
         end
 
         prefix, suffix = $1, ''

test/links_test.rb

@@ -222,6 +222,12 @@
     assert_xpath '//a', convert_string('\http://asciidoc.org is the project page for AsciiDoc.'), 0
   end
 
+  test 'escaped inline qualified url as macro should not create link' do
+    output = convert_string '\http://asciidoc.org[asciidoc.org] is the project page for AsciiDoc.'
+    assert_xpath '//a', output, 0
+    assert_xpath '//p[starts-with(text(), "http://asciidoc.org[asciidoc.org]")]', output, 1
+  end
+
   test 'url in link macro with at (@) sign should not create mailto link' do
     assert_xpath '//a[@href="http://xircles.codehaus.org/lists/dev@geb.codehaus.org"][text()="subscribe"]', convert_string('http://xircles.codehaus.org/lists/dev@geb.codehaus.org[subscribe]')
   end