Properly render sort variable variable as composite.

HateoasSortHandlerMethodArgumentResolver now renders the sort template variable as composite to properly indicate that it can be submitted multiple times.

Fixes GH-2531.
Original pull request GH-2945.

src/main/java/org/springframework/data/web/HateoasSortHandlerMethodArgumentResolver.java

@@ -35,6 +35,7 @@
  * @author Oliver Gierke
  * @author Thomas Darimont
  * @author Nick Williams
+ * @author Julien Béti
  */
 public class HateoasSortHandlerMethodArgumentResolver extends SortHandlerMethodArgumentResolver
 		implements UriComponentsContributor {
@@ -58,7 +59,7 @@ public TemplateVariables getSortTemplateVariables(MethodParameter parameter, Uri
 
 		String description = String.format("pagination.%s.description", sortParameter);
 		TemplateVariable.VariableType type = append ? REQUEST_PARAM_CONTINUED : REQUEST_PARAM;
-		return new TemplateVariables(new TemplateVariable(sortParameter, type, description));
+		return new TemplateVariables(new TemplateVariable(sortParameter, type, description).composite());
 	}
 
 	@Override

src/test/java/org/springframework/data/web/HateoasPageableHandlerMethodArgumentResolverUnitTests.java

@@ -28,6 +28,7 @@
  * Unit tests for {@link HateoasPageableHandlerMethodArgumentResolver}.
  *
  * @author Oliver Gierke
+ * @author Julien Béti
  */
 class HateoasPageableHandlerMethodArgumentResolverUnitTests
 		extends PageableHandlerMethodArgumentResolverUnitTests {
@@ -66,18 +67,18 @@ void preventsPageSizeFromExceedingMayValueIfConfiguredOnWrite() throws Exception
 		assertUriStringFor(PageRequest.of(0, 200), "page=0&size=100");
 	}
 
-	@Test // DATACMNS-418
+	@Test // DATACMNS-418, GH-2531
 	void appendsTemplateVariablesCorrectly() {
 
-		assertTemplateEnrichment("/foo", "{?page,size,sort}");
-		assertTemplateEnrichment("/foo?bar=1", "{&page,size,sort}");
-		assertTemplateEnrichment("/foo?page=1", "{&size,sort}");
-		assertTemplateEnrichment("/foo?page=1&size=10", "{&sort}");
+		assertTemplateEnrichment("/foo", "{?page,size,sort*}");
+		assertTemplateEnrichment("/foo?bar=1", "{&page,size,sort*}");
+		assertTemplateEnrichment("/foo?page=1", "{&size,sort*}");
+		assertTemplateEnrichment("/foo?page=1&size=10", "{&sort*}");
 		assertTemplateEnrichment("/foo?page=1&sort=foo,asc", "{&size}");
 		assertTemplateEnrichment("/foo?page=1&size=10&sort=foo,asc", "");
 	}
 
-	@Test // DATACMNS-418
+	@Test // DATACMNS-418, GH-2531
 	void returnsCustomizedTemplateVariables() {
 
 		var uriComponents = UriComponentsBuilder.fromPath("/foo").build();
@@ -86,7 +87,7 @@ void returnsCustomizedTemplateVariables() {
 		resolver.setPageParameterName("foo");
 		var variables = resolver.getPaginationTemplateVariables(null, uriComponents).toString();
 
-		assertThat(variables).isEqualTo("{?foo,size,sort}");
+		assertThat(variables).isEqualTo("{?foo,size,sort*}");
 	}
 
 	@Test // DATACMNS-563

src/test/java/org/springframework/data/web/HateoasSortHandlerMethodArgumentResolverUnitTests.java

@@ -28,6 +28,7 @@
  * Unit tests for {@link HateoasSortHandlerMethodArgumentResolver}
  *
  * @author Oliver Gierke
+ * @author Julien Béti
  */
 class HateoasSortHandlerMethodArgumentResolverUnitTests extends SortHandlerMethodArgumentResolverUnitTests {
 
@@ -46,13 +47,13 @@ void replacesExistingRequestParameters() throws Exception {
 		assertUriStringFor(SORT, "/?sort=firstname,lastname,desc", "/?sort=foo,asc");
 	}
 
-	@Test // DATACMNS-418
+	@Test // DATACMNS-418, GH-2531
 	void returnCorrectTemplateVariables() {
 
 		var uriComponents = UriComponentsBuilder.fromPath("/").build();
 
 		var resolver = new HateoasSortHandlerMethodArgumentResolver();
-		assertThat(resolver.getSortTemplateVariables(null, uriComponents).toString()).isEqualTo("{?sort}");
+		assertThat(resolver.getSortTemplateVariables(null, uriComponents).toString()).isEqualTo("{?sort*}");
 	}
 
 	private void assertUriStringFor(Sort sort, String expected) throws Exception {