From 7c408c9644431573e2b1ce498fa135e3efb40657 Mon Sep 17 00:00:00 2001
From: John McGuin <john@waysoftware.dev>
Date: Thu, 5 Sep 2024 16:24:55 -0600
Subject: [PATCH 1/2] feat: supports match, to: functional_plug

follows pattern in `forward` macro to check
if the target is an Elixir module or function.
---
 lib/plug/router.ex | 38 ++++++++++++++++++++++++--------------
 1 file changed, 24 insertions(+), 14 deletions(-)

diff --git a/lib/plug/router.ex b/lib/plug/router.ex
index 4c9c07f9..0c754b74 100644
--- a/lib/plug/router.ex
+++ b/lib/plug/router.ex
@@ -267,22 +267,31 @@ defmodule Plug.Router do
     init_mode = Module.get_attribute(env.module, :plug_builder_opts)[:init_mode]
 
     defs =
-      for {callback, {mod, opts}} <- router_to do
-        if init_mode == :runtime do
-          quote do
-            defp unquote(callback)(conn, _opts) do
-              unquote(mod).call(conn, unquote(mod).init(unquote(Macro.escape(opts))))
+      for {callback, {target, opts}} <- router_to do
+        case {init_mode, Atom.to_string(target)} do
+          {:runtime, "Elixir." <> _} ->
+            quote do
+              defp unquote(callback)(conn, _opts) do
+                unquote(target).call(conn, unquote(target).init(unquote(Macro.escape(opts))))
+              end
+            end
+
+          {_, "Elixir." <> _} ->
+            opts = target.init(opts)
+
+            quote do
+              defp unquote(callback)(conn, _opts) do
+                require unquote(target)
+                unquote(target).call(conn, unquote(Macro.escape(opts)))
+              end
             end
-          end
-        else
-          opts = mod.init(opts)
-
-          quote do
-            defp unquote(callback)(conn, _opts) do
-              require unquote(mod)
-              unquote(mod).call(conn, unquote(Macro.escape(opts)))
+
+          _ ->
+            quote do
+              defp unquote(callback)(conn, _opts) do
+                unquote(target)(conn, unquote(Macro.escape(opts)))
+              end
             end
-          end
         end
       end
 
@@ -575,6 +584,7 @@ defmodule Plug.Router do
     router_to = Module.get_attribute(module, :plug_router_to)
     callback = :"plug_router_to_#{map_size(router_to)}"
     router_to = Map.put(router_to, callback, {to, init_opts})
+
     Module.put_attribute(module, :plug_router_to, router_to)
     {Macro.var(callback, nil), options}
   end

From aed4519eafccf69326d4e99a8b04cb1e08dff38b Mon Sep 17 00:00:00 2001
From: John McGuin <john@waysoftware.dev>
Date: Thu, 5 Sep 2024 16:26:50 -0600
Subject: [PATCH 2/2] test: match, to: functional_plug

---
 test/plug/router_test.exs | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/test/plug/router_test.exs b/test/plug/router_test.exs
index b6fed1e3..3886fba2 100644
--- a/test/plug/router_test.exs
+++ b/test/plug/router_test.exs
@@ -206,12 +206,18 @@ defmodule Plug.RouterTest do
     forward "/plug/init_opts", to: plug, init_opts: opts, private: %{baz: :qux}
 
     forward "/plug/forward_local", to: :forward_local
+    match "/plug/match_local", to: :match_local
     forward "/plug/forward_local_opts", to: :forward_local, init_opts: opts, private: %{baz: :qux}
+    match "/plug/match_local_opts", to: :match_local, init_opts: opts, private: %{baz: :qux}
 
     def forward_local(conn, opts) do
       resp(conn, 200, "#{inspect(opts)}")
     end
 
+    def match_local(conn, opts) do
+      resp(conn, 200, "#{inspect(opts)}")
+    end
+
     match _ do
       resp(conn, 404, "oops")
     end
@@ -586,12 +592,23 @@ defmodule Plug.RouterTest do
     assert conn.resp_body == "[]"
   end
 
+  test "matches to a function plug" do
+    conn = call(Sample, conn(:get, "/plug/match_local"))
+    assert conn.resp_body == "[]"
+  end
+
   test "forwards to a function plug with options" do
     conn = call(Sample, conn(:get, "/plug/forward_local_opts"))
     assert conn.private[:baz] == :qux
     assert conn.resp_body == ":hello"
   end
 
+  test "matches to a function plug with options" do
+    conn = call(Sample, conn(:get, "/plug/match_local_opts"))
+    assert conn.private[:baz] == :qux
+    assert conn.resp_body == ":hello"
+  end
+
   test "emit start and stop event when router dispatches" do
     start_router_id = {:start, :rand.uniform(100)}
     stop_router_id = {:stop, :rand.uniform(100)}