Allow nested maps for package's "extra" field (#1096)

Author: san650

lib/mix/tasks/hex.build.ex

@@ -371,7 +371,8 @@ defmodule Mix.Tasks.Hex.Build do
   end
 
   defp format_metadata_value(map) when is_map(map) do
-    "\n    " <> Enum.map_join(map, "\n    ", fn {key, val} -> "#{key}: #{val}" end)
+    "\n    " <>
+      Enum.map_join(map, "\n    ", fn {key, val} -> "#{key}: #{format_metadata_value(val)}" end)
   end
 
   defp format_metadata_value(value) do

test/mix/tasks/hex.publish_test.exs

@@ -542,7 +542,7 @@ defmodule Mix.Tasks.Hex.PublishTest do
       assert_received {:mix_shell, :info, ["Building publish_with_metadata 0.0.3"]}
       assert_received {:mix_shell, :info, ["  Files:"]}
       assert_received {:mix_shell, :info, ["    myfile.txt"]}
-      assert_received {:mix_shell, :info, ["  Extra: \n    c: d"]}
+      assert_received {:mix_shell, :info, ["  Extra: \n    c: \n    d: e"]}
 
       assert_received {:mix_shell, :info, ["Publishing package using http://" <> _]}
 

test/support/release_samples.ex

@@ -87,7 +87,7 @@ defmodule ReleaseMeta.MixProject do
         files: ["myfile.txt", "missing.txt", "missing/*"],
         licenses: ["Apache-2.0"],
         links: %{"a" => "http://a"},
-        extra: %{"c" => "d"}
+        extra: %{"c" => %{"d" => "e"}}
       ]
     ]
   end