handle undefined port with custom scheme

Author: tfiedlerdejanze

lib/elixir/lib/uri.ex

@@ -656,9 +656,12 @@ defmodule URI do
         scheme = String.downcase(scheme, :ascii)
 
         case map do
-          %{port: port} when port != :undefined ->
+          %{port: port} when is_integer(port) ->
             %{uri | scheme: scheme}
 
+          %{port: :undefined} ->
+            %{uri | scheme: scheme, port: default_port(scheme)}
+
           %{} ->
             case default_port(scheme) do
               nil -> %{uri | scheme: scheme}

lib/elixir/test/elixir/uri_test.exs

@@ -97,20 +97,6 @@ defmodule URITest do
       assert URI.new("") == {:ok, %URI{}}
     end
 
-    test "missing port part after host never resolves to :undefined" do
-      assert URI.new("//https://www.example.com") ==
-               {:ok,
-                %URI{
-                  scheme: nil,
-                  userinfo: nil,
-                  host: "https",
-                  port: nil,
-                  path: "//www.example.com",
-                  query: nil,
-                  fragment: nil
-                }}
-    end
-
     test "errors on bad URIs" do
       assert URI.new("/>") == {:error, ">"}
       assert URI.new(":https") == {:error, ":"}
@@ -291,6 +277,32 @@ defmodule URITest do
     test "preserves an empty query" do
       assert URI.new!("http://foo.com/?").query == ""
     end
+
+    test "without scheme, undefined port after host translates to nil" do
+      assert URI.new!("//https://www.example.com") ==
+               %URI{
+                 scheme: nil,
+                 userinfo: nil,
+                 host: "https",
+                 port: nil,
+                 path: "//www.example.com",
+                 query: nil,
+                 fragment: nil
+               }
+    end
+
+    test "with scheme, undefined port after host translates to nil" do
+      assert URI.new!("myscheme://myhost:/path/info") ==
+               %URI{
+                 scheme: "myscheme",
+                 userinfo: nil,
+                 host: "myhost",
+                 port: nil,
+                 path: "/path/info",
+                 query: nil,
+                 fragment: nil
+               }
+    end
   end
 
   test "http://http://http://@http://http://?http://#http://" do