Registering an ExclusionStrategy for deserialization affects serialized output

[Marcono1234]

Gson version

2.9.1

Java / Android version

Java 17

Description

Registering an ExclusionStrategy which excludes a subclass on deserialization affects the serialized output for that class.
The underlying issue is the same as for #1833 and #2032.

Maybe at this point there should be a method TypeAdapter.usesReflection() whose default implementation returns false but which can be overridden by subclasses. This would avoid all this special-casing, and it would also allow third-party adapters to make use of this.

Important: Fixing this might affect the exclusion handling for serialization, so maybe this cannot be solved easily.

Reproduction steps

static class Base {
}
static class Sub extends Base {
  int i = 0;
}
static class Container {
  Base b = new Sub();
}

@Test
public void test() {
  ExclusionStrategy exclusionStrategy = new ExclusionStrategy() {
    @Override public boolean shouldSkipField(FieldAttributes f) {
      return false;
    }

    @Override public boolean shouldSkipClass(Class<?> clazz) {
      return clazz == Sub.class;
    }
  };

  Gson gson = new GsonBuilder()
    .registerTypeAdapter(Base.class, new TypeAdapter<Base>() {
      @Override public Base read(JsonReader in) throws IOException {
        throw new AssertionError("not needed");
      }

      @Override public void write(JsonWriter out, Base value) throws IOException {
        out.value("custom-adapter");
      }
    })
    // Registering a *de*serialization exclusion affects serialization
    .addDeserializationExclusionStrategy(exclusionStrategy)
    .create();

  assertEquals("{\"b\":\"custom-adapter\"}", gson.toJson(new Container()));
}

When the ExclusionStrategy is registered, TypeAdapterRuntimeTypeWrapper erroneously considers the adapter created by Excluder (which wraps a reflective adapter) as non-reflective. The assertion above fails because the output is erroneously {"b":{"i":0}}.