fix: only catch our invalid uri errors

lib/rack/canonical_host.rb

@@ -15,13 +15,13 @@ def call(env)
       host = evaluate_host(env)
       redirect = Redirect.new(env, host, options)
 
-      if redirect.canonical?
-        app.call(env)
-      else
-        redirect.response
+      begin
+        return redirect.response unless redirect.canonical?
+      rescue Addressable::URI::InvalidURIError
+        return [400, { Rack::CONTENT_TYPE => "text/plain", Rack::CONTENT_LENGTH => "0" }, []]
       end
-    rescue Addressable::URI::InvalidURIError
-      [400, { Rack::CONTENT_TYPE => "text/plain", Rack::CONTENT_LENGTH => "0" }, []]
+
+      app.call(env)
     end
 
   protected

spec/rack/canonical_host_spec.rb

@@ -84,6 +84,20 @@ def call_app
       end
     end
 
+
+    context 'when the app happens to have an invalid uri error' do
+      before do
+        allow(inner_app)
+          .to receive(:call)
+          .with(env)
+          .and_raise(Addressable::URI::InvalidURIError)
+      end
+
+      it 'explodes as expected' do
+        expect { call_app }.to raise_error(Addressable::URI::InvalidURIError)
+      end
+    end
+
     context 'with an X-Forwarded-Host' do
       let(:url) { 'http://proxy.test/full/path' }