Fix DTO projection instantiation.

We now correctly instantiate DTO projection classes by using the actual constructor argument type. Previously, we did not update the conversion context to fetch the correct type but used the type of the DTO projection class instead of the constructor argument.

Closes #1292

Author: mp911de

spring-data-cassandra/src/main/java/org/springframework/data/cassandra/core/convert/MappingCassandraConverter.java

@@ -1466,11 +1466,11 @@ public <T> T getParameterValue(Parameter<T, CassandraPersistentProperty> paramet
 						name, entity.getType()));
 			}
 
-			return (T) getReadValue(context, provider, property);
+			return (T) getReadValue(context.forProperty(property.getName()), provider, property);
 		}
 
 		@Nullable
-		private <T> CassandraPersistentProperty getPersistentProperty(String name, TypeInformation<?> typeInformation,
+		private CassandraPersistentProperty getPersistentProperty(String name, TypeInformation<?> typeInformation,
 				MergedAnnotations annotations) {
 
 			CassandraPersistentProperty property = entity.getPersistentProperty(name);

spring-data-cassandra/src/test/java/org/springframework/data/cassandra/core/convert/MappingCassandraConverterUnitTests.java

@@ -1078,6 +1078,33 @@ void shouldConsiderNestedProjections() {
 		assertThat(result.getTuple().getOne()).isEqualTo("One");
 	}
 
+	@Test // GH-1202
+	void shouldCreateDtoProjectionsThroughConstructor() {
+
+		DefaultTupleValue value = new DefaultTupleValue(
+				new DefaultTupleType(Arrays.asList(DataTypes.ASCII, DataTypes.ASCII, DataTypes.ASCII)));
+
+		value.setString(0, "Zero");
+		value.setString(1, "One");
+		value.setString(2, "Two");
+
+		EntityProjectionIntrospector introspector = EntityProjectionIntrospector.create(
+				new SpelAwareProxyProjectionFactory(), EntityProjectionIntrospector.ProjectionPredicate.typeHierarchy(),
+				this.mappingContext);
+
+		rowMock = RowMockUtil.newRowMock(RowMockUtil.column("firstname", "Heisenberg", DataTypes.ASCII),
+				RowMockUtil.column("tuple", value, value.getType()));
+
+		EntityProjection<TupleAndNameProjection, WithMappedTuple> projection = introspector
+				.introspect(TupleAndNameProjection.class, WithMappedTuple.class);
+
+		TupleAndNameProjection result = this.mappingCassandraConverter.project(projection, rowMock);
+
+		assertThat(result.getName().getFirstname()).isEqualTo("Heisenberg");
+		assertThat(result.getTuple().zero).isEqualTo("Zero");
+		assertThat(result.getTuple().one).isEqualTo("One");
+	}
+
 	private static List<Object> getValues(Map<CqlIdentifier, Object> statement) {
 		return new ArrayList<>(statement.values());
 	}
@@ -1340,16 +1367,30 @@ public WithColumnAnnotationInConstructor(@Column("fn") String firstname, @Column
 	private static class WithMappedTuple {
 
 		String firstname;
+		@Embedded.Nullable Name name;
 		TupleWithElementAnnotationInConstructor tuple;
 	}
 
+	@lombok.Value
+	private static class Name {
+		String firstname;
+	}
+
 	@Data
 	private static class WithMappedTupleDtoProjection {
 
 		String firstname;
 		TupleProjection tuple;
 	}
 
+	@lombok.Value
+	private static class TupleAndNameProjection {
+
+		@Embedded.Nullable Name name;
+
+		TupleWithElementAnnotationInConstructor tuple;
+	}
+
 	private static interface TupleProjection {
 
 		String getZero();