[gjs: 4/14] fundamental: Also allow to transform a fundamental to a compatible gvalue

[Philip Chimento <pchimento src gnome org>]

commit ba6293fe61fa9ff4298b910e270abfb5b2b3a563
Author: Marco Trevisan (Treviño) <mail 3v1n0 net>
Date:   Thu Apr 8 18:29:38 2021 +0200

    fundamental: Also allow to transform a fundamental to a compatible gvalue

 gi/fundamental.cpp                    |  7 +++++++
 installed-tests/js/testFundamental.js | 12 ++++++++++++
 2 files changed, 19 insertions(+)
---
diff --git a/gi/fundamental.cpp b/gi/fundamental.cpp
index d3221193..e117907e 100644
--- a/gi/fundamental.cpp
+++ b/gi/fundamental.cpp
@@ -470,6 +470,13 @@ bool FundamentalBase::to_gvalue(JSContext* cx, JS::HandleObject obj,
         if (g_value_type_compatible(instance->gtype(), G_VALUE_TYPE(gvalue))) {
             g_value_set_instance(gvalue, instance->m_ptr);
             return true;
+        } else if (g_value_type_transformable(instance->gtype(),
+                                              G_VALUE_TYPE(gvalue))) {
+            GValue instance_value = {0};
+            g_value_init(&instance_value, instance->gtype());
+            g_value_set_instance(&instance_value, instance->m_ptr);
+            g_value_transform(&instance_value, gvalue);
+            return true;
         }
 
         gjs_throw(cx,
diff --git a/installed-tests/js/testFundamental.js b/installed-tests/js/testFundamental.js
index 4b555b61..0c939573 100644
--- a/installed-tests/js/testFundamental.js
+++ b/installed-tests/js/testFundamental.js
@@ -96,4 +96,16 @@ describe('Fundamental type support', function () {
         expect(() => obj.emit('test-fundamental-no-funcs-subtype', fund)).toThrowError(
             / RegressTestFundamentalObjectNoGetSetFunc .* conversion to a GValue.* 
RegressTestFundamentalSubObjectNoGetSetFunc/);
     }).pend('https://gitlab.gnome.org/GNOME/gobject-introspection/-/merge_requests/268');
+
+    it('can marshal a custom fundamental type into a transformable type', function () {
+        Regress.TestFundamentalObjectNoGetSetFunc.make_compatible_with_fundamental_sub_object();
+        const fund = new Regress.TestFundamentalObjectNoGetSetFunc('foo');
+        const obj = new TestObj();
+        const signalSpy = jasmine.createSpy('signalSpy');
+        obj.connect('test-fundamental-value-funcs-subtype', signalSpy);
+        obj.connect('test-fundamental-value-funcs-subtype', (_o, f) =>
+            expect(f instanceof Regress.TestFundamentalSubObject).toBeTrue());
+        obj.emit('test-fundamental-value-funcs-subtype', fund);
+        expect(signalSpy).toHaveBeenCalled();
+    }).pend('https://gitlab.gnome.org/GNOME/gobject-introspection/-/merge_requests/268');
 });