AsyncFeign doesn't work with type parameters on the base api interface.

[voron86]

I tried to use next interface with AsyncFeign:

@Headers({ "Content-Type: application/json", "Accept: application/json" })
public interface V1AsyncEndpoint<T> {

  @RequestLine("POST /api/v1/projects/{project}/{resource}/byids")
  @Headers("Authorization: Bearer {token}")
  CompletableFuture<T> getPageByIds(
      @Param("token") String token,
      @Param("project") String project,
      @Param("resource") String resource,
      @Param("items") Collection<Long> ids,
      @Param("ignoreUnknownIds") boolean ignoreUnknownIds,
      @Nullable
      @Param("aggregatedProperties") Collection<String> aggregatedProperties);
}

for Type:

class Data {
String a;
Long b;
}

But getPageByIds always returns com.google.gson.internal.LinkedTreeMap and then I get java.util.concurrent.CompletionException: java.lang.ClassCastException: class com.google.gson.internal.LinkedTreeMap

If I use

@Headers({ "Content-Type: application/json", "Accept: application/json" })
public interface V1AsyncEndpoint {

  @RequestLine("POST /api/v1/projects/{project}/{resource}/byids")
  @Headers("Authorization: Bearer {token}")
  CompletableFuture<Data> getPageByIds(
      @Param("token") String token,
      @Param("project") String project,
      @Param("resource") String resource,
      @Param("items") Collection<Long> ids,
      @Param("ignoreUnknownIds") boolean ignoreUnknownIds,
      @Nullable
      @Param("aggregatedProperties") Collection<String> aggregatedProperties);
}

everything works correctly.

I've made short debugging and I noticed the AsyncFeign decoder gets T as type instead of Data when deserialisation happens.

I use version: 11.8

[voron86]

Fixed in 11.9 (#1623)