really fix scalar enum namespace handling

It is actually important to consider the field name when provided,
otherwise we can incorrectly match fields with different names!

instant-xml-macros/src/de.rs

@@ -77,7 +77,13 @@ fn deserialize_scalar_enum(
         impl #impl_generics FromXml<'xml> for #ident #ty_generics #where_clause {
             #[inline]
             fn matches(id: ::instant_xml::Id<'_>, field: Option<::instant_xml::Id<'_>>) -> bool {
-                id == ::instant_xml::Id { ns: #default_namespace, name: id.name }
+                id == ::instant_xml::Id {
+                    ns: #default_namespace,
+                    name: match field {
+                        Some(fid) => fid.name,
+                        None => id.name,
+                    },
+                }
             }
 
             fn deserialize<'cx>(
@@ -99,7 +105,7 @@ fn deserialize_scalar_enum(
                 let value = match cow_str.as_ref() {
                     #variants
                     _ => return Err(Error::UnexpectedValue(
-                        format!("enum variant not found for '{}'", cow_str),
+                        format!("enum variant not found for '{}' in field {}", cow_str, field),
                     )),
                 };
 

instant-xml/tests/scalar-enum.rs

@@ -42,3 +42,49 @@ fn scalar_enum_ns() {
     assert_eq!(xml, to_string(&v).unwrap());
     assert_eq!(v, from_str(xml).unwrap());
 }
+
+const DIDL: &str = "DIDL";
+const UPNP: &str = "UPNP";
+const DC: &str = "DC";
+
+#[derive(Debug, FromXml, PartialEq, ToXml)]
+#[xml(rename = "DIDL-Lite", ns(DIDL, dc = DC, upnp = UPNP))]
+struct DidlLite {
+    item: Vec<UpnpItem>,
+}
+
+#[derive(Debug, FromXml, PartialEq, ToXml)]
+#[xml(rename = "item", ns(DIDL))]
+struct UpnpItem {
+    class: Option<ObjectClass>,
+}
+
+#[derive(Debug, Clone, PartialEq, FromXml, ToXml)]
+#[xml(rename = "class", scalar, ns(UPNP, upnp = UPNP))]
+enum ObjectClass {
+    #[xml(rename = "object.item.audioItem.musicTrack")]
+    MusicTrack,
+    #[xml(rename = "object.item.audioItem.audioBroadcast")]
+    AudioBroadcast,
+    #[xml(rename = "object.container.playlistContainer")]
+    PlayList,
+}
+
+#[test]
+fn scalar_enum_ns_match() {
+    let v = DidlLite {
+        item: vec![UpnpItem {
+            class: Some(ObjectClass::AudioBroadcast),
+        }],
+    };
+
+    // Keep the `upnp::mimeType` element after `upnp::class` to ensure that
+    // we tickle a `DuplicateValue` error if we don't match correctly.
+    let xml = r#"<DIDL-Lite xmlns="DIDL" xmlns:upnp="UPNP" xmlns:dc="DC" xmlns:dlna="DLNA">
+        <item>
+            <upnp:class>object.item.audioItem.audioBroadcast</upnp:class>
+            <upnp:mimeType>audio/flac</upnp:mimeType>
+        </item>
+    </DIDL-Lite>"#;
+    assert_eq!(v, from_str(xml).unwrap());
+}