[gjs/gnome-3-38] arg-cache: Throw an error when handling unsupported caller-allocates types

[Philip Chimento <pchimento src gnome org>]

commit 2954a31252add3cb2822ebed61ab879d7360f070
Author: Marco Trevisan (Treviño) <mail 3v1n0 net>
Date:   Mon Sep 7 20:14:51 2020 +0200

    arg-cache: Throw an error when handling unsupported caller-allocates types
    
    Previous of commit aa28329b7 we were assuming that all the
    caller-allocates function were using an interface tag, that was wrong
    but at the same time we don't yet support any other type of
    caller-allocats function yet [1], so if we detect one type that we don't
    support we should just throw with some valuable error as we used to do and
    not just crash.
    
    Otherwise it would be impossible to test a solution for bug [2].
    
    [1] https://gitlab.gnome.org/GNOME/gjs/-/issues/106
    [2] https://gitlab.gnome.org/GNOME/gjs/-/issues/344

 gi/arg-cache.cpp | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)
---
diff --git a/gi/arg-cache.cpp b/gi/arg-cache.cpp
index 6e193a4b4..d49576ef5 100644
--- a/gi/arg-cache.cpp
+++ b/gi/arg-cache.cpp
@@ -1576,8 +1576,15 @@ bool gjs_arg_cache_build_arg(JSContext* cx, GjsArgumentCache* self,
     *inc_counter_out = true;
 
     GITypeTag type_tag = g_type_info_get_tag(&self->type_info);
-    if (direction == GI_DIRECTION_OUT && type_tag == GI_TYPE_TAG_INTERFACE &&
-        g_arg_info_is_caller_allocates(arg)) {
+    if (direction == GI_DIRECTION_OUT && g_arg_info_is_caller_allocates(arg)) {
+        if (type_tag != GI_TYPE_TAG_INTERFACE) {
+            gjs_throw(cx,
+                      "Unsupported type %s for argument %s with (out "
+                      "caller-allocates)",
+                      g_type_tag_to_string(type_tag), self->arg_name);
+            return false;
+        }
+
         GjsAutoBaseInfo interface_info =
             g_type_info_get_interface(&self->type_info);
         g_assert(interface_info);