[seed] Void function with one OUT arg should use arg as return value

[Danilo Cesar Lemes de Paula <danilocesar src gnome org>]

commit eb749b146d81c26550999c3f1206a33888669ce7
Author: Danilo Cesar Lemes de Paula <danilo cesar collabora co uk>
Date:   Tue Jun 7 10:52:21 2016 -0300

    Void function with one OUT arg should use arg as return value
    
    A void method with only one OUT argument should return this argument
    itself. The old logic returns an array with only one index, which is
    weird and not compatible with the gjs approach.

 libseed/seed-engine.c |   19 +++++++++++++++----
 1 files changed, 15 insertions(+), 4 deletions(-)
---
diff --git a/libseed/seed-engine.c b/libseed/seed-engine.c
index b4539ff..1651789 100644
--- a/libseed/seed-engine.c
+++ b/libseed/seed-engine.c
@@ -530,6 +530,7 @@ seed_gobject_method_invoked(JSContextRef ctx,
     gint length_arg_pos = 0;
     guint64 array_len = 0;
     gint array_return_value_count = 0;
+    gboolean return_only_one_out = false;
 
     info = JSObjectGetPrivate(function);
 
@@ -788,11 +789,17 @@ seed_gobject_method_invoked(JSContextRef ctx,
     }
 
     if (tag == GI_TYPE_TAG_VOID) {
-        // if we have no out args - returns undefined
-        // otherwise we return an object, and put the return values into that
-        // along with supporting the old object.value way
+        // * if we have no out args - returns undefined
+        // * if we have *one* out_arg but no return type,
+        //   do nothing here and return the OUT as return later.
+        // * otherwise we return an object, and put the return values into that
+        //   along with supporting the old object.value way
         if (n_out_args < 1)
             retval_ref = JSValueMakeUndefined(ctx);
+        else if (n_out_args == 1){
+            return_only_one_out = true;
+            use_return_as_out = 1;
+        }
         else {
             retval_ref = JSObjectMake(ctx, NULL, NULL);
             use_return_as_out = 1;
@@ -985,7 +992,9 @@ seed_gobject_method_invoked(JSContextRef ctx,
         // if we add it to the return argument and/or the first out arguement
 
         if (use_return_as_out) {
-            if (force_return_array) {
+            if (return_only_one_out) {
+                retval_ref = jsout_val;
+            } else if (force_return_array) {
                 _add_jsvalue_in_array(ctx, (JSObjectRef) retval_ref,
                                       array_return_value_count++, jsout_val);
             } else {
@@ -1013,6 +1022,8 @@ seed_gobject_method_invoked(JSContextRef ctx,
     }
 
 invoke_return:
+    SEED_NOTE(INVOCATION, "END seed_object_method_invoked for function %s",
+              g_base_info_get_name(info));
 
     // clean up everything..
     for (i = 0; (i < (n_args)); i++)