Embind: Clarify poor UNO exception support

As UNO exceptions are not derived from std::exception in C++, the corresponding
JS object's name property is present but has undefined value.  And the UNO
Message property is not present at all.

Change-Id: Ibe152377e5970faa8a518c77b5171d9f3c160f38
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/165885
Tested-by: Jenkins
Reviewed-by: Stephan Bergmann <stephan.bergmann@allotropia.de>

udkapi/org/libreoffice/embindtest/XTest.idl

@@ -112,6 +112,7 @@ interface XTest {
     boolean isSequenceEnum([in] sequence<Enum> value);
     sequence<Struct> getSequenceStruct();
     boolean isSequenceStruct([in] sequence<Struct> value);
+    void throwRuntimeException();
 };
 
 }; }; };

unotest/source/embindtest/embindtest.cxx

@@ -11,6 +11,7 @@
 
 #include <com/sun/star/uno/Any.hxx>
 #include <com/sun/star/uno/Reference.hxx>
+#include <com/sun/star/uno/RuntimeException.hpp>
 #include <com/sun/star/uno/Sequence.hxx>
 #include <com/sun/star/uno/Type.hxx>
 #include <cppu/unotype.hxx>
@@ -496,6 +497,11 @@ class Test : public cppu::WeakImplHelper<org::libreoffice::embindtest::XTest>
                       { 123456, 100.75, u"bazzz"_ustr }
                   };
     }
+
+    void SAL_CALL throwRuntimeException() override
+    {
+        throw css::uno::RuntimeException(u"test"_ustr);
+    }
 };
 }
 

unotest/source/embindtest/embindtest.js

@@ -537,6 +537,13 @@ Module.addOnPostRun(function() {
     console.assert(test.isFloat(uno.org.libreoffice.embindtest.Constants.Float));
     console.assert(uno.org.libreoffice.embindtest.Constants.Double === 100.5);
     console.assert(test.isDouble(uno.org.libreoffice.embindtest.Constants.Double));
+    try {
+        test.throwRuntimeException();
+   } catch (e) {
+       console.assert(e.name === 'com::sun::star::uno::RuntimeException');
+       console.assert(e.message === undefined); //TODO
+       //TODO: console.assert(e.Message.startsWith('test'));
+   }
 });
 
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