rebar3Relx: add beamDeps support

pkgs/development/beam-modules/rebar3-release.nix

@@ -1,8 +1,10 @@
-{ stdenv, writeText, erlang, rebar3, openssl,
+{ stdenv, erlang, rebar3WithPlugins, openssl,
   lib }:
 
 { name, version
 , src
+, beamDeps ? []
+, buildPlugins ? []
 , checkouts ? null
 , releaseType
 , buildInputs ? []
@@ -12,7 +14,6 @@
 , buildPhase ? null
 , configurePhase ? null
 , meta ? {}
-, enableDebugInfo ? false
 , ... }@attrs:
 
 with lib;
@@ -27,28 +28,42 @@ let
     (_: v: v != null)
     { inherit setupHook configurePhase buildPhase installPhase; };
 
-  pkg = self: stdenv.mkDerivation (attrs // {
+  # When using the `beamDeps` argument, it is important that we use
+  # `rebar3WithPlugins` here even when there are no plugins. The vanilla
+  # `rebar3` package is an escript archive with bundled dependencies which can
+  # interfere with those in the app we are trying to build. `rebar3WithPlugins`
+  # doesn't have this issue since it puts its own deps last on the code path.
+  rebar3 = rebar3WithPlugins {
+    plugins = buildPlugins;
+  };
+
+  pkg =
+    assert beamDeps != [] -> checkouts == null;
+    self: stdenv.mkDerivation (attrs // {
 
     name = "${name}-${version}";
     inherit version;
 
-    buildInputs = buildInputs ++ [ erlang rebar3 openssl ];
-    propagatedBuildInputs = [checkouts];
+    buildInputs = buildInputs ++ [ erlang rebar3 openssl ] ++ beamDeps;
 
     dontStrip = true;
 
     inherit src;
 
-    setupHook = writeText "setupHook.sh" ''
-       addToSearchPath ERL_LIBS "$1/lib/erlang/lib/"
-    '';
-
     configurePhase = ''
       runHook preConfigure
-      ${if checkouts != null then
-          "cp --no-preserve=all -R ${checkouts}/_checkouts ."
-        else
-          ""}
+      ${lib.optionalString (checkouts != null)
+      "cp --no-preserve=all -R ${checkouts}/_checkouts ."}
+      ${# Prevent rebar3 from trying to manage deps
+      lib.optionalString (beamDeps != [ ]) ''
+        erl -noshell -eval '
+          {ok, Terms0} = file:consult("rebar.config"),
+          Terms = lists:keydelete(deps, 1, Terms0),
+          ok = file:write_file("rebar.config", [io_lib:format("~tp.~n", [T]) || T <- Terms]),
+          init:stop(0)
+        '
+        rm -f rebar.lock
+      ''}
       runHook postConfigure
     '';