resolves #4576 encode spaces in mailto links as %20, in accordance with RFC 3986, instead of using + (PR #4591)

4 files changed, 10 insertions, 6 deletions

diff --git a/CHANGELOG.adoc b/CHANGELOG.adoc
index 6fe7130d..d08f75ff 100644
--- a/CHANGELOG.adoc
+++ b/CHANGELOG.adoc
@@ -43,6 +43,7 @@ Compliance::
   * Disallow the use of dot (`.`) in the name of a named element attribute (#4147)
   * Disallow the use of the left square bracket in an attribute list on formatted text (#4306)
   * Update stylesheet to use break-after in place of page-break-before/after/inside (#3466)
+  * Encode spaces in mailto links as %20, in accordance with RFC 3986, instead of using + (#4576)
   * Drop support for Ruby < 2.7 and JRuby < 9.2
   * Update latest JRuby in CI workflow to 9.4.2.0
 
diff --git a/lib/asciidoctor/helpers.rb b/lib/asciidoctor/helpers.rb
index fc5a37f0..e92aa978 100644
--- a/lib/asciidoctor/helpers.rb
+++ b/lib/asciidoctor/helpers.rb
@@ -146,10 +146,13 @@ module Helpers
         })
       )
     end
+  elsif (CGI = ::CGI).respond_to? :escapeURIComponent
+    def encode_uri_component str
+      CGI.escapeURIComponent str
+    end
   else
-    CGI = ::CGI
     def encode_uri_component str
-      CGI.escape str
+      (CGI.escape str).gsub '+', '%20'
     end
   end
 
diff --git a/test/helpers_test.rb b/test/helpers_test.rb
index 38b0eeba..cfc2fe00 100644
--- a/test/helpers_test.rb
+++ b/test/helpers_test.rb
@@ -6,7 +6,7 @@ context 'Helpers' do
   context 'URI Encoding' do
     test 'should URI encode non-word characters generally' do
       given = ' !*/%&?\\='
-      expect = '+%21%2A%2F%25%26%3F%5C%3D'
+      expect = '%20%21%2A%2F%25%26%3F%5C%3D'
       assert_equal expect, (Asciidoctor::Helpers.encode_uri_component given)
     end
 
diff --git a/test/substitutions_test.rb b/test/substitutions_test.rb
index a4c6c37d..4cd74ebd 100644
--- a/test/substitutions_test.rb
+++ b/test/substitutions_test.rb
@@ -677,17 +677,17 @@ context 'Substitutions' do
 
     test 'a mailto macro with text and subject should be interpreted as a mailto link' do
       para = block_from_string 'mailto:doc.writer@asciidoc.org[Doc Writer, Pull request]'
-      assert_equal '<a href="mailto:doc.writer@asciidoc.org?subject=Pull+request">Doc Writer</a>', para.sub_macros(para.source)
+      assert_equal '<a href="mailto:doc.writer@asciidoc.org?subject=Pull%20request">Doc Writer</a>', para.sub_macros(para.source)
     end
 
     test 'a mailto macro with text, subject and body should be interpreted as a mailto link' do
       para = block_from_string 'mailto:doc.writer@asciidoc.org[Doc Writer, Pull request, Please accept my pull request]'
-      assert_equal '<a href="mailto:doc.writer@asciidoc.org?subject=Pull+request&amp;body=Please+accept+my+pull+request">Doc Writer</a>', para.sub_macros(para.source)
+      assert_equal '<a href="mailto:doc.writer@asciidoc.org?subject=Pull%20request&amp;body=Please%20accept%20my%20pull%20request">Doc Writer</a>', para.sub_macros(para.source)
     end
 
     test 'a mailto macro with subject and body only should use e-mail as text' do
       para = block_from_string 'mailto:doc.writer@asciidoc.org[,Pull request,Please accept my pull request]'
-      assert_equal '<a href="mailto:doc.writer@asciidoc.org?subject=Pull+request&amp;body=Please+accept+my+pull+request">doc.writer@asciidoc.org</a>', para.sub_macros(para.source)
+      assert_equal '<a href="mailto:doc.writer@asciidoc.org?subject=Pull%20request&amp;body=Please%20accept%20my%20pull%20request">doc.writer@asciidoc.org</a>', para.sub_macros(para.source)
     end
 
     test 'a mailto macro supports id and role attributes' do