fix(engine): don't check for @JsonCreator annotation and only take @JsonValue into account

packages/java/parser-jvm-plugin-backbone/src/main/java/com/vaadin/hilla/parser/plugins/backbone/JsonValuePlugin.java

@@ -1,6 +1,5 @@
 package com.vaadin.hilla.parser.plugins.backbone;
 
-import com.fasterxml.jackson.annotation.JsonCreator;
 import com.fasterxml.jackson.annotation.JsonValue;
 import com.vaadin.hilla.parser.core.AbstractPlugin;
 import com.vaadin.hilla.parser.core.Node;
@@ -16,11 +15,9 @@
 import java.util.HashMap;
 import java.util.Map;
 import java.util.Optional;
-import java.util.stream.Stream;
 
 /**
- * Adds support for Jackson's {@code JsonValue} and {@code JsonCreator}
- * annotations.
+ * Adds support for Jackson's {@code JsonValue} annotation.
  */
 public class JsonValuePlugin
         extends AbstractPlugin<BackbonePluginConfiguration> {
@@ -67,40 +64,8 @@ private Optional<Class<?>> getValueType(Class<?> cls) {
     }
 
     private Optional<Class<?>> findValueType(Class<?> cls) {
-        // First of all, we check that the `@JsonValue` annotation is
-        // used on a method of the class.
-        Stream<Class<?>> candidates = Arrays.stream(cls.getMethods())
+        return Arrays.stream(cls.getMethods())
                 .filter(method -> method.isAnnotationPresent(JsonValue.class))
-                .map(Method::getReturnType);
-        var jsonValue = candidates.findAny();
-
-        // Then we check that the class has a `@JsonCreator` annotation
-        // on a method or on a constructor. This is a basic check, we
-        // could also check that they use the same type.
-        var jsonCreator = Stream
-                .concat(Arrays.stream(cls.getMethods()),
-                        Arrays.stream(cls.getConstructors()))
-                .filter(executable -> executable
-                        .isAnnotationPresent(JsonCreator.class))
-                .findAny();
-
-        // Classes having only one of those annotation are malformed in Hilla as
-        // they break the generator or, at least, make data transfer impossible,
-        // so we throw an exception for those.
-        if (jsonValue.isPresent() ^ jsonCreator.isPresent()) {
-            throw new MalformedValueTypeException("Class " + cls.getName()
-                    + " has only one of @JsonValue and @JsonCreator."
-                    + " Hilla only supports classes with both annotations.");
-        }
-
-        return jsonValue;
-    }
-
-    // this shouldn't be a runtime exception, but `resolve` doesn't allow
-    // checked exceptions
-    public static class MalformedValueTypeException extends RuntimeException {
-        public MalformedValueTypeException(String message) {
-            super(message);
-        }
+                .map(Method::getReturnType).findAny();
     }
 }

packages/java/parser-jvm-plugin-backbone/src/test/java/com/vaadin/hilla/parser/plugins/backbone/jsonvaluenojsoncreator/JsonCreatorNoJsonValueEndpoint.java

@@ -0,0 +1,43 @@
+package com.vaadin.hilla.parser.plugins.backbone.jsonvaluenojsoncreator;
+
+import com.fasterxml.jackson.annotation.JsonCreator;
+import com.fasterxml.jackson.annotation.JsonProperty;
+
+@Endpoint
+public class JsonCreatorNoJsonValueEndpoint {
+
+    public static class User {
+
+        private final String name;
+        private final int age;
+
+        // Default constructor
+        public User() {
+            this.name = "Unknown";
+            this.age = 0;
+        }
+
+        // Constructor used during deserialization
+        @JsonCreator
+        public User(@JsonProperty("name") String n,
+                @JsonProperty("age") int a) {
+            name = n;
+            age = a;
+        }
+
+        public String getName() {
+            return name;
+        }
+
+        public int getAge() {
+            return age;
+        }
+    }
+
+    public User getUser() {
+        return new User("John Doe", 42);
+    }
+
+    public void setUser(User user) {
+    }
+}

packages/java/parser-jvm-plugin-backbone/src/test/java/com/vaadin/hilla/parser/plugins/backbone/jsonvaluenojsoncreator/JsonValueNoJsonCreatorTest.java

@@ -2,25 +2,27 @@
 
 import com.vaadin.hilla.parser.core.Parser;
 import com.vaadin.hilla.parser.plugins.backbone.BackbonePlugin;
-import com.vaadin.hilla.parser.plugins.backbone.JsonValuePlugin.MalformedValueTypeException;
 import com.vaadin.hilla.parser.plugins.backbone.test.helpers.TestHelper;
 import org.junit.jupiter.api.Test;
 
+import java.io.IOException;
+import java.net.URISyntaxException;
 import java.util.List;
 import java.util.Set;
 
-import static org.junit.jupiter.api.Assertions.assertThrows;
-
 public class JsonValueNoJsonCreatorTest {
     private final TestHelper helper = new TestHelper(getClass());
 
     @Test
-    public void should_ThrowExceptionWhenOnlyJsonValueIsUsed() {
-        assertThrows(MalformedValueTypeException.class, () -> {
-            new Parser().classPath(Set.of(helper.getTargetDir().toString()))
-                    .endpointAnnotations(List.of(Endpoint.class))
-                    .addPlugin(new BackbonePlugin())
-                    .execute(List.of(JsonValueNoJsonCreatorEndpoint.class));
-        });
+    public void should_notChangeOutcomeAccordingToJsonCreator()
+            throws IOException, URISyntaxException {
+        var openAPI = new Parser()
+                .classPath(Set.of(helper.getTargetDir().toString()))
+                .endpointAnnotations(List.of(Endpoint.class))
+                .addPlugin(new BackbonePlugin())
+                .execute(List.of(JsonValueNoJsonCreatorEndpoint.class,
+                        JsonCreatorNoJsonValueEndpoint.class));
+
+        helper.executeParserWithConfig(openAPI);
     }
 }

packages/java/parser-jvm-plugin-backbone/src/test/resources/com/vaadin/hilla/parser/plugins/backbone/jsonvaluenojsoncreator/openapi.json

@@ -0,0 +1,148 @@
+{
+  "openapi": "3.0.1",
+  "info": {
+    "title": "Hilla Application",
+    "version": "1.0.0"
+  },
+  "servers": [
+    {
+      "url": "http://localhost:8080/connect",
+      "description": "Hilla Backend"
+    }
+  ],
+  "tags": [
+    {
+      "name": "JsonValueNoJsonCreatorEndpoint",
+      "x-class-name": "com.vaadin.hilla.parser.plugins.backbone.jsonvaluenojsoncreator.JsonValueNoJsonCreatorEndpoint"
+    },
+    {
+      "name": "JsonCreatorNoJsonValueEndpoint",
+      "x-class-name": "com.vaadin.hilla.parser.plugins.backbone.jsonvaluenojsoncreator.JsonCreatorNoJsonValueEndpoint"
+    }
+  ],
+  "paths": {
+    "/JsonValueNoJsonCreatorEndpoint/getEmail": {
+      "post": {
+        "tags": [
+          "JsonValueNoJsonCreatorEndpoint"
+        ],
+        "operationId": "JsonValueNoJsonCreatorEndpoint_getEmail_POST",
+        "responses": {
+          "200": {
+            "description": "",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "type": "string",
+                  "nullable": true
+                }
+              }
+            }
+          }
+        }
+      }
+    },
+    "/JsonValueNoJsonCreatorEndpoint/setEmail": {
+      "post": {
+        "tags": [
+          "JsonValueNoJsonCreatorEndpoint"
+        ],
+        "operationId": "JsonValueNoJsonCreatorEndpoint_setEmail_POST",
+        "requestBody": {
+          "content": {
+            "application/json": {
+              "schema": {
+                "type": "object",
+                "properties": {
+                  "email": {
+                    "type": "string",
+                    "nullable": true
+                  }
+                }
+              }
+            }
+          }
+        },
+        "responses": {
+          "200": {
+            "description": ""
+          }
+        }
+      }
+    },
+    "/JsonCreatorNoJsonValueEndpoint/getUser": {
+      "post": {
+        "tags": [
+          "JsonCreatorNoJsonValueEndpoint"
+        ],
+        "operationId": "JsonCreatorNoJsonValueEndpoint_getUser_POST",
+        "responses": {
+          "200": {
+            "description": "",
+            "content": {
+              "application/json": {
+                "schema": {
+                  "nullable": true,
+                  "anyOf": [
+                    {
+                      "$ref": "#/components/schemas/com.vaadin.hilla.parser.plugins.backbone.jsonvaluenojsoncreator.JsonCreatorNoJsonValueEndpoint$User"
+                    }
+                  ]
+                }
+              }
+            }
+          }
+        }
+      }
+    },
+    "/JsonCreatorNoJsonValueEndpoint/setUser": {
+      "post": {
+        "tags": [
+          "JsonCreatorNoJsonValueEndpoint"
+        ],
+        "operationId": "JsonCreatorNoJsonValueEndpoint_setUser_POST",
+        "requestBody": {
+          "content": {
+            "application/json": {
+              "schema": {
+                "type": "object",
+                "properties": {
+                  "user": {
+                    "nullable": true,
+                    "anyOf": [
+                      {
+                        "$ref": "#/components/schemas/com.vaadin.hilla.parser.plugins.backbone.jsonvaluenojsoncreator.JsonCreatorNoJsonValueEndpoint$User"
+                      }
+                    ]
+                  }
+                }
+              }
+            }
+          }
+        },
+        "responses": {
+          "200": {
+            "description": ""
+          }
+        }
+      }
+    }
+  },
+  "components": {
+    "schemas": {
+      "com.vaadin.hilla.parser.plugins.backbone.jsonvaluenojsoncreator.JsonCreatorNoJsonValueEndpoint$User": {
+        "type": "object",
+        "properties": {
+          "name": {
+            "type": "string",
+            "nullable": true
+          },
+          "age": {
+            "type": "integer",
+            "format": "int32"
+          }
+        }
+      }
+    }
+  }
+}