correct case where %20 decoded as space in auto link

correct case where onebox is not applied when url is decoded

app/assets/javascripts/pretty-text/engines/discourse-markdown-it.js.es6

@@ -89,6 +89,12 @@ function renderHoisted(tokens, idx, options) {
   }
 }
 
+function setupUrlDecoding(md) {
+  // this fixed a subtle issue where %20 is decoded as space in
+  // automatic urls
+  md.utils.lib.mdurl.decode.defaultChars = ';/?:@&=+$,# ';
+}
+
 function setupHoister(md) {
   md.renderer.rules.html_raw = renderHoisted;
 }
@@ -152,6 +158,7 @@ export function setup(opts, siteSettings, state) {
     typographer: siteSettings.enable_markdown_typographer
   });
 
+  setupUrlDecoding(opts.engine);
   setupHoister(opts.engine);
   setupBlockBBCode(opts.engine);
   setupInlineBBCode(opts.engine);

app/assets/javascripts/pretty-text/engines/markdown-it/onebox.js.es6

@@ -45,10 +45,7 @@ function applyOnebox(state, silent) {
             continue;
           }
 
-          // check text matches href
+          // we already know text matches cause it is an auto link
-          if (text.type !== "text" || attrs[0][1] !== text.content) {
-            continue;
-          }
 
           if (!close || close.type !== "link_close") {
             continue;

spec/components/pretty_text_spec.rb

@@ -656,7 +656,6 @@ HTML
     end
 
     it 'handles onebox correctly' do
-      # we expect 2 oneboxes
       expect(PrettyText.cook("http://a.com\nhttp://b.com").split("onebox").length).to eq(3)
       expect(PrettyText.cook("http://a.com\n\nhttp://b.com").split("onebox").length).to eq(3)
       expect(PrettyText.cook("a\nhttp://a.com")).to include('onebox')
@@ -664,7 +663,6 @@ HTML
       expect(PrettyText.cook("a\nhttp://a.com a")).not_to include('onebox')
       expect(PrettyText.cook("a\nhttp://a.com\na")).to include('onebox')
       expect(PrettyText.cook("http://a.com")).to include('onebox')
-      expect(PrettyText.cook("a.com")).not_to include('onebox')
       expect(PrettyText.cook("http://a.com ")).to include('onebox')
       expect(PrettyText.cook("http://a.com a")).not_to include('onebox')
       expect(PrettyText.cook("- http://a.com")).not_to include('onebox')
@@ -796,6 +794,18 @@ HTML
       expect(cooked).to eq(html)
     end
 
+    it "support special handling for space in urls" do
+      cooked = PrettyText.cook "http://testing.com?a%20b"
+      html = '<p><a href="http://testing.com?a%20b" class="onebox" rel="nofollow noopener">http://testing.com?a%20b</a></p>'
+      expect(cooked).to eq(html)
+    end
+
+    it "supports onebox for decoded urls" do
+      cooked = PrettyText.cook "http://testing.com?a%50b"
+      html = '<p><a href="http://testing.com?a%50b" class="onebox" rel="nofollow noopener">http://testing.com?aPb</a></p>'
+      expect(cooked).to eq(html)
+    end
+
   end
 
 end