Fix regression on URI.parse/1, closes #11363

Author: josevalim

lib/elixir/lib/uri.ex

@@ -668,8 +668,15 @@ defmodule URI do
         {:error, _} -> %URI{path: path}
       end
 
-  Also note this function sets the authority field, but the field has been
-  deprecated and it is not set by `URI.new!/1` and `URI.new/1`.
+  There are two differencws in the behaviour of this function compared to
+  `URI.new/1`:
+
+    * This function sets the deprecated authority field
+
+    * This function sets the path to `nil` when it is empty,
+      while `new/1` consider the path always exists and sets it
+      to an empty string
+
   """
   # TODO: Deprecate me at least on v1.17
   @doc deprecated: "Use URI.new/1 or URI.new!/1 instead"
@@ -706,6 +713,7 @@ defmodule URI do
                 ],
                 parts
 
+    path = nillify(path)
     scheme = nillify(scheme)
     query = nillify_query(query_with_question_mark)
     {authority, userinfo, host, port} = split_authority(authority_with_slashes)
@@ -817,6 +825,8 @@ defmodule URI do
     merge(parse(base), parse(rel))
   end
 
+  # TODO: Deprecate me on Elixir v1.19
+  defp merge_paths(nil, rel_path), do: merge_paths("/", rel_path)
   defp merge_paths("", rel_path), do: merge_paths("/", rel_path)
   defp merge_paths(_, "/" <> _ = rel_path), do: remove_dot_segments_from_path(rel_path)
 

lib/elixir/test/elixir/uri_test.exs

@@ -449,7 +449,7 @@ defmodule URITest do
         query: nil,
         fragment: nil,
         port: 443,
-        path: "",
+        path: nil,
         userinfo: nil
       }
 
@@ -551,7 +551,7 @@ defmodule URITest do
       expected_uri = %URI{
         scheme: "http",
         host: "foo.com",
-        path: "",
+        path: nil,
         query: nil,
         fragment: nil,
         port: 4444,
@@ -564,7 +564,7 @@ defmodule URITest do
       expected_uri = %URI{
         scheme: "https",
         host: "foo.com",
-        path: "",
+        path: nil,
         query: nil,
         fragment: nil,
         port: 443,
@@ -577,7 +577,7 @@ defmodule URITest do
       expected_uri = %URI{
         scheme: "http",
         host: "foo.com",
-        path: "",
+        path: nil,
         query: nil,
         fragment: nil,
         port: 4444,
@@ -655,5 +655,11 @@ defmodule URITest do
     test "preserves an empty query" do
       assert URI.parse("http://foo.com/?").query == ""
     end
+
+    test "merges empty path" do
+      base = URI.parse("http://example.com")
+      assert URI.merge(base, "/foo") |> to_string == "http://example.com/foo"
+      assert URI.merge(base, "foo") |> to_string == "http://example.com/foo"
+    end
   end
 end