Cleanup and simplify deprecated option handling

src/rebar_app_utils.erl

@@ -175,27 +175,7 @@ is_skipped_app(ThisApp, TargetApps) ->
     end.
 
 get_apps() ->
-    get_global_cs_opt(app, apps).
+    rebar_utils:get_deprecated_global(app, apps, "soon").
 
 get_skip_apps() ->
-    get_global_cs_opt(skip_app, skip_apps).
-
-get_global_cs_opt(Old, New) ->
-    Apps = rebar_config:get_global(New, undefined),
-    case rebar_config:get_global(Old, undefined) of
-        undefined ->
-            case Apps of
-                undefined ->
-                    undefined;
-                Apps ->
-                    Apps
-            end;
-        App ->
-            rebar_utils:deprecated(Old, Old, New, "soon"),
-            case Apps of
-                undefined ->
-                    App;
-                Apps ->
-                    string:join([App, Apps], ",")
-            end
-    end.
+    rebar_utils:get_deprecated_global(skip_app, skip_apps, "soon").

src/rebar_utils.erl

@@ -44,7 +44,8 @@
          expand_code_path/0,
          deprecated/4, deprecated/5,
          expand_env_variable/3,
-         vcs_vsn/2]).
+         vcs_vsn/2,
+         get_deprecated_global/3]).
 
 -include("rebar.hrl").
 
@@ -232,6 +233,20 @@ vcs_vsn(Vcs, Dir) ->
             end
     end.
 
+get_deprecated_global(OldOpt, NewOpt, When) ->
+    case rebar_config:get_global(OldOpt, undefined) of
+        undefined ->
+            case rebar_config:get_global(NewOpt, undefined) of
+                undefined ->
+                    undefined;
+                New ->
+                    New
+            end;
+        Old ->
+            deprecated(OldOpt, OldOpt, NewOpt, When),
+            Old
+    end.
+
 %% ====================================================================
 %% Internal functions
 %% ====================================================================