relx: do not discard command line parameters when parameter is not in config

fix #2967

Author: sg2342

apps/rebar/src/rebar_relx.erl

@@ -235,13 +235,16 @@ maybe_obey_command_args(RelxConfig, Opts, Args) ->
                      undefined ->
                          Acc;
                      V ->
-                         replace_all_instance(Opt, V, Acc)
+                         add_or_replace_all_instance(Opt, V, Acc)
                  end
         end, RelxConfig, Args).
 
-replace_all_instance(Opt, Value, RelxConfig) ->
-    lists:map(fun({K, _}) when K =:= Opt -> {K, Value};
-            (Other) -> Other end, RelxConfig).
+add_or_replace_all_instance(Opt, Value, RelxConfig) ->
+    case lists:keymember(Opt, 1, RelxConfig) of
+        true -> lists:map(fun({K, _}) when K =:= Opt -> {K, Value};
+                             (Other) -> Other end, RelxConfig);
+        false -> [{Opt, Value} | RelxConfig]
+    end.
 
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