erlang support: seperate hex and rebar3 support

Building Hex packages is a superset of building with rebar3. There is no
need to force folks that use rebar3 but not hex to build with hex. This
commit seperates the rebar3 specific bits and the hex specific bits into
seperate functions that can be used independently.

pkgs/development/erlang-modules/build-hex.nix

@@ -1,86 +1,18 @@
-{ stdenv, writeText, erlang, rebar3, openssl, libyaml, fetchHex, fetchFromGitHub,
-  rebar3-pc, buildEnv }:
+{ stdenv, buildRebar3, fetchHex }:
 
-{ name, version, sha256 ? false
-, src ? null
-, setupHook ? null
+{ name, version, sha256
 , hexPkg ? name
-, buildInputs ? [], erlangDeps ? [], pluginDeps ? []
-, postPatch ? ""
-, compilePorts ? false
-, meta ? {}
 , ... }@attrs:
 
 with stdenv.lib;
 
 let
-  plugins = pluginDeps ++ (if compilePorts then [rebar3-pc] else []);
+  pkg = self: buildRebar3 (attrs // {
 
-
-  shell = drv: stdenv.mkDerivation {
-          name = "interactive-shell-${drv.name}";
-          buildInputs = [ drv ];
-    };
-
-  pkg = self: stdenv.mkDerivation (attrs // {
-
-    name = "${name}-${version}";
-    inherit version;
-
-    buildInputs = buildInputs ++ [ erlang rebar3 openssl libyaml ];
-    propagatedBuildInputs = erlangDeps ++ plugins;
-
-    src = if src == null then fetchHex {
+    src = fetchHex {
       pkg = hexPkg;
       inherit version;
       inherit sha256;
-    } else src;
-
-    setupHook = if setupHook == null
-    then writeText "setupHook.sh" ''
-       addToSearchPath ERL_LIBS "$1/lib/erlang/lib/"
-    ''
-    else setupHook;
-
-    postPatch = ''
-      rm -f rebar rebar3
-    '';
-
-    configurePhase = ''
-      runHook preConfigure
-      rebar3-nix-bootstrap
-      runHook postConfigure
-    '';
-
-    buildPhase = ''
-      runHook preBuild
-      HOME=. rebar3 compile
-      ${if compilePorts then ''
-        HOME=. rebar3 pc compile
-      '' else ''''}
-      runHook postBuild
-    '';
-
-    installPhase = ''
-      runHook preInstall
-      mkdir -p "$out/lib/erlang/lib/${name}-${version}"
-      for reldir in src ebin priv include; do
-        fd="_build/default/lib/${name}/$reldir"
-        [ -d "$fd" ] || continue
-        cp -Hrt "$out/lib/erlang/lib/${name}-${version}" "$fd"
-        success=1
-      done
-      runHook postInstall
-    '';
-
-    meta = {
-      inherit (erlang.meta) platforms;
-    } // meta;
-
-    passthru = {
-      packageName = name;
-      env = shell self;
-      inherit erlangDeps;
     };
   });
 in

pkgs/development/erlang-modules/build-rebar3.nix

@@ -0,0 +1,82 @@
+{ stdenv, writeText, erlang, rebar3, openssl, libyaml, fetchHex, fetchFromGitHub,
+  rebar3-pc, buildEnv }:
+
+{ name, version
+, src
+, setupHook ? null
+, buildInputs ? [], erlangDeps ? [], pluginDeps ? []
+, postPatch ? ""
+, compilePorts ? false
+, meta ? {}
+, ... }@attrs:
+
+with stdenv.lib;
+
+let
+  plugins = pluginDeps ++ (if compilePorts then [rebar3-pc] else []);
+
+
+  shell = drv: stdenv.mkDerivation {
+          name = "interactive-shell-${drv.name}";
+          buildInputs = [ drv ];
+    };
+
+  pkg = self: stdenv.mkDerivation (attrs // {
+
+    name = "${name}-${version}";
+    inherit version;
+
+    buildInputs = buildInputs ++ [ erlang rebar3 openssl libyaml ];
+    propagatedBuildInputs = erlangDeps ++ plugins;
+
+    inherit src;
+
+    setupHook = if setupHook == null
+    then writeText "setupHook.sh" ''
+       addToSearchPath ERL_LIBS "$1/lib/erlang/lib/"
+    ''
+    else setupHook;
+
+    postPatch = ''
+      rm -f rebar rebar3
+    '';
+
+    configurePhase = ''
+      runHook preConfigure
+      rebar3-nix-bootstrap
+      runHook postConfigure
+    '';
+
+    buildPhase = ''
+      runHook preBuild
+      HOME=. rebar3 compile
+      ${if compilePorts then ''
+        HOME=. rebar3 pc compile
+      '' else ''''}
+      runHook postBuild
+    '';
+
+    installPhase = ''
+      runHook preInstall
+      mkdir -p "$out/lib/erlang/lib/${name}-${version}"
+      for reldir in src ebin priv include; do
+        fd="_build/default/lib/${name}/$reldir"
+        [ -d "$fd" ] || continue
+        cp -Hrt "$out/lib/erlang/lib/${name}-${version}" "$fd"
+        success=1
+      done
+      runHook postInstall
+    '';
+
+    meta = {
+      inherit (erlang.meta) platforms;
+    } // meta;
+
+    passthru = {
+      packageName = name;
+      env = shell self;
+      inherit erlangDeps;
+    };
+  });
+in
+  fix pkg

pkgs/development/erlang-modules/default.nix

@@ -4,6 +4,8 @@ let
   self = rec {
     hex = import ./hex-packages.nix { callPackage = self.callPackage; };
     callPackage = pkgs.lib.callPackageWith (pkgs // self // hex);
+
+    buildRebar3 = callPackage ./build-rebar3.nix {};
     buildHex = callPackage ./build-hex.nix {};
   };
 in self // self.hex