Fix updating nested collection fields using JSON Patch

spring-data-rest-webmvc/src/main/java/org/springframework/data/rest/webmvc/json/patch/JsonPointerMapping.java

@@ -74,7 +74,6 @@ private String verify(String pointer, Class<?> type, BiFunction<String, Class<?>
 			return pointer;
 		}
 
-		PropertyPath base = null;
 		StringBuilder result = new StringBuilder();
 		TypeInformation<?> currentType = ClassTypeInformation.from(type);
 
@@ -108,13 +107,11 @@ private String verify(String pointer, Class<?> type, BiFunction<String, Class<?>
 					.orElseThrow(() -> reject(segment, rejectType, pointer, qualifier));
 
 			try {
-				base = base == null ? PropertyPath.from(property, type) : base.nested(segment);
+				currentType = PropertyPath.from(property, currentType).getTypeInformation();
 			} catch (PropertyReferenceException o_O) {
 				throw reject(segment, rejectType, pointer, qualifier);
 			}
 
-			currentType = base.getTypeInformation();
-
 			result.append("/").append(property);
 		}
 

spring-data-rest-webmvc/src/main/java/org/springframework/data/rest/webmvc/json/patch/SpelPath.java

@@ -521,7 +521,7 @@ public SkippedPropertyPath nested(String segment) {
 					return SkippedPropertyPath.of(path.nested(segment), false);
 				}
 
-				TypeInformation<?> typeInformation = path.getTypeInformation();
+				TypeInformation<?> typeInformation = path.getLeafProperty().getTypeInformation();
 
 				return typeInformation.isMap() || typeInformation.isCollectionLike() //
 						? SkippedPropertyPath.of(path, true) //

spring-data-rest-webmvc/src/test/java/org/springframework/data/rest/webmvc/json/patch/SpelPathUnitTests.java

@@ -54,6 +54,7 @@ void setUp() {
 		context.getPersistentEntity(MapWrapper.class);
 		context.getPersistentEntity(Todo.class);
 		context.getPersistentEntity(Person.class);
+		context.getPersistentEntity(Library.class);
 
 		PersistentEntities entities = new PersistentEntities(Arrays.asList(context));
 		BindContextFactory factory = new PersistentEntitiesBindContextFactory(entities,
@@ -167,6 +168,29 @@ void mapsRenamedProperty() {
 		assertThat(path.getExpressionString()).isEqualTo("renamed");
 	}
 
+	@Test // #2401
+	void getsLeafTypeForAppendToCollectionBelowIndexedCollectionElement() {
+
+		WritingOperations path = SpelPath.untyped("/catalog/books/0/reviews/-") //
+				.bindForWrite(Library.class, context);
+
+		assertThat(path.getExpressionString()).isEqualTo("catalog.books[0].reviews$[true]");
+		assertThat(path.getLeafType()).isEqualTo(Review.class);
+	}
+
+	@Test // #2401
+	void appendsToCollectionBelowIndexedCollectionElement() {
+
+		Library library = new Library();
+		library.catalog.books.add(new Book());
+
+		Review review = new Review();
+		AddOperation.of("/catalog/books/0/reviews/-", review) //
+				.perform(library, Library.class, context);
+
+		assertThat(library.catalog.books.get(0).reviews).containsExactly(review);
+	}
+
 	@Test // #2233
 	void bindsDatesProperly() {
 
@@ -252,4 +276,58 @@ public void setPeopleByInt(Map<Integer, Person> peopleByInt) {
 			this.peopleByInt = peopleByInt;
 		}
 	}
+
+	// #2401
+
+	static class Library {
+
+		Catalog catalog = new Catalog();
+
+		public Catalog getCatalog() {
+			return this.catalog;
+		}
+
+		public void setCatalog(Catalog catalog) {
+			this.catalog = catalog;
+		}
+	}
+
+	static class Catalog {
+
+		List<Book> books = new ArrayList<>();
+
+		public List<Book> getBooks() {
+			return this.books;
+		}
+
+		public void setBooks(List<Book> books) {
+			this.books = books;
+		}
+	}
+
+	static class Book {
+
+		List<Review> reviews = new ArrayList<>();
+
+		public List<Review> getReviews() {
+			return this.reviews;
+		}
+
+		public void setReviews(List<Review> reviews) {
+			this.reviews = reviews;
+		}
+	}
+
+	static class Review {
+
+		String text;
+
+		public String getText() {
+			return this.text;
+		}
+
+		public void setText(String text) {
+			this.text = text;
+		}
+	}
 }