Add ref-link CSS class for undecorated ref links

Using the "Bitter" font for body text changes the height at which text
decoration is rendered for links.  Thus the Firefox-specific hack to
hide underlines for code ref links no longer works.

This commit uses postprocessing to add a `ref-link` CSS class to code
ref links.  The `link_to` helper now also sets `ref-link` as the default
CSS class when given an `RDoc::CodeObject`.  The `ref-link` class is
styled with `text-decoration: none`.  Thus code ref links will have no
underline in all browsers.

lib/rdoc/generator/template/rails/_module_nav.rhtml

@@ -15,7 +15,7 @@
   <ul class="nav__list">
     <% methods.each do |rdoc_method| %>
       <li><%= link_to short_name(rdoc_method), rdoc_method,
-                class: "nav__method-link#{"--singleton" if rdoc_method.singleton}" %></li>
+                class: "ref-link nav__method-link#{"--singleton" if rdoc_method.singleton}" %></li>
     <% end %>
   </ul>
 <% end %>

lib/rdoc/generator/template/rails/resources/css/main.css

@@ -112,23 +112,16 @@ a {
   }
 }
 
-a:has(> code):not(:has(> :not(code))) {
-  text-decoration: none;
-}
-
-/* TODO: Remove this hack when Firefox supports `:has()` */
-@supports not selector(:has(*)) {
-  a code {
-    text-decoration: underline var(--body-bg);
-  }
-}
-
 .external-link {
   padding-left: 1.3em;
   background: url('../i/external-link.svg') no-repeat;
   background-size: 1.1em;
 }
 
+.ref-link {
+  text-decoration: none;
+}
+
 .query-button {
   border: none;
   text-align: left;
@@ -302,13 +295,6 @@ th
   border-radius: 3px;
 }
 
-/* TODO: Remove this hack when Firefox supports `:has()` */
-@supports not selector(:has(*)) {
-  .description a code {
-    text-decoration: underline var(--code-bg);
-  }
-}
-
 @media (hover: hover) {
   .description a:hover code {
     box-shadow: 0 0 0 1px;
@@ -630,10 +616,6 @@ html {
   word-break: break-word;
 }
 
-.nav__outline a {
-  text-decoration: underline;
-}
-
 
 .nav__list {
   padding: 0;

lib/rdoc/generator/template/rails/resources/js/main.js

@@ -5,7 +5,7 @@ document.addEventListener("turbo:load", () => {
   const searchOutput = document.getElementById("results");
   const search = new Search(searchInput, searchOutput, (url, module, method, summary) =>
     `<div class="results__result">
-      <a class="result__link" href="${url}">
+      <a class="ref-link result__link" href="${url}">
         <code class="result__module">${module.replaceAll("::", "::<wbr>")}</code>
         <code class="result__method">${method || ""}</code>
       </a>

lib/sdoc/helpers.rb

@@ -12,13 +12,19 @@ module SDoc::Helpers
   def link_to(text, url = nil, html_attributes = {})
     url, html_attributes = nil, url if url.is_a?(Hash)
     url ||= text
-    attribute_string = html_attributes.map { |name, value| %( #{name}="#{h value}") }.join
 
-    %(<a href="#{_link_url url}"#{attribute_string}>#{_link_body text}</a>)
-  end
+    text = _link_body(text)
+
+    if url.is_a?(RDoc::CodeObject)
+      url = "/#{url.path}"
+      default_class = "ref-link" if text.start_with?("<code>") && text.end_with?("</code>")
+    end
 
-  def _link_url(url)
-    h(url.is_a?(RDoc::CodeObject) ? "/#{url.path}" : url)
+    html_attributes = html_attributes.transform_keys(&:to_s)
+    html_attributes = { "href" => url, "class" => default_class }.compact.merge(html_attributes)
+
+    attribute_string = html_attributes.map { |name, value| %( #{name}="#{h value}") }.join
+    %(<a#{attribute_string}>#{text}</a>)
   end
 
   def _link_body(text)

lib/sdoc/postprocessor.rb

@@ -11,6 +11,7 @@ def process(rendered)
 
     rebase_urls!(document)
     version_rails_guides_urls!(document)
+    add_ref_link_classes!(document)
     unify_h1_headings!(document)
     highlight_code_blocks!(document)
 
@@ -70,6 +71,14 @@ def version_url(url, version)
     uri.to_s
   end
 
+  def add_ref_link_classes!(document)
+    document.css(".description a code").each do |element|
+      if element.parent.children.one?
+        element.parent.add_class("ref-link")
+      end
+    end
+  end
+
   def unify_h1_headings!(document)
     if h1 = document.at_css("#context > .description h1:first-child")
       if hgroup = document.at_css("#content > hgroup")

spec/helpers_spec.rb

@@ -150,6 +150,24 @@ module Foo; class Bar; def qux; end; end; end
           must_equal %(<a href="/#{code_object.path}">text</a>)
       end
     end
+
+    it "uses .ref-link as the default class when creating a <code> link to an RDoc::CodeObject" do
+      rdoc_module = rdoc_top_level_for(<<~RUBY).find_module_named("Foo::Bar")
+        module Foo; module Bar; end
+      RUBY
+
+      _(@helpers.link_to(rdoc_module)).
+        must_equal %(<a href="/#{rdoc_module.path}" class="ref-link">#{@helpers.full_name(rdoc_module)}</a>)
+
+      _(@helpers.link_to("<code>Bar</code>", rdoc_module)).
+        must_equal %(<a href="/#{rdoc_module.path}" class="ref-link"><code>Bar</code></a>)
+
+      _(@helpers.link_to("<code>Bar</code>", rdoc_module, class: "other")).
+        must_equal %(<a href="/#{rdoc_module.path}" class="other"><code>Bar</code></a>)
+
+      _(@helpers.link_to("Jump to <code>Bar</code>", rdoc_module)).
+        must_equal %(<a href="/#{rdoc_module.path}">Jump to <code>Bar</code></a>)
+    end
   end
 
   describe "#link_to_if" do

spec/postprocessor_spec.rb

@@ -58,6 +58,26 @@
       end
     end
 
+    it "adds .ref-link class to code ref links" do
+      rendered = <<~HTML
+        <div class="description">
+          <a href="classes/Foo.html"><code>Foo</code></a>
+          <a href="classes/Foo.html">not ref link</a>
+          <a href="classes/Foo.html">not <code>ref</code> link</a>
+        </div>
+      HTML
+
+      expected = <<~HTML
+        <div class="description">
+          <a href="classes/Foo.html" class="ref-link"><code>Foo</code></a>
+          <a href="classes/Foo.html">not ref link</a>
+          <a href="classes/Foo.html">not <code>ref</code> link</a>
+        </div>
+      HTML
+
+      _(SDoc::Postprocessor.process(rendered)).must_include expected
+    end
+
     it "unifies <h1> headings for a context" do
       rendered = <<~HTML
         <div id="content">