[BUG][JAVA] Problem with request serialization / deserialization in case of oneOf caused by PR #20939

[GooDer]

This problem is related to change in #20939 related to bug report #20938.

So it worked in version 7.14 and it is not working since actual 7.19.

I agree that correct behavior should be that only mapped discriminator should be included in generated interface for parent type, but it now breaks serialization / deserialization in client vs server communication.

Since parent interface contains these annotations it will override property of discriminator via Jackson mapper to simple class name but server now expect to receive explicit mapping that we have in yaml definition.

I will borrow example from original bug report with slight alternation:

    FruitRequest:
      discriminator:
        mapping:
          APPLE: '#/components/schemas/AppleRequest'
          BANANA: '#/components/schemas/BananaRequest'
        propertyName: fruitType
      oneOf:
      - $ref: '#/components/schemas/AppleRequest'
      - $ref: '#/components/schemas/BananaRequest'
      properties:
        fruitType:
          $ref: '#/components/schemas/FruitType'
      required:
      - fruitType
      type: object
      x-one-of-name: Fruit
    AppleRequest:
      properties:
        seeds:
          type: integer
      required:
      - seeds
      type: object
    BananaRequest:
      properties:
        length:
          type: integer
      required:
      - length
      type: object

then we will have:

@JsonIgnoreProperties(
    value = {"fruitType"},
    allowSetters = true
)
@JsonTypeInfo(
    use = Id.NAME,
    include = As.PROPERTY,
    property = "fruitType",
    visible = true
)
@JsonSubTypes({
  @JsonSubTypes.Type(value = Apple.class, name = "APPLE"),
  @JsonSubTypes.Type(value = Banana.class, name = "BANANA"),
  @JsonSubTypes.Type(value = Apple.class, name = "AppleRequest"),    // <-- not any more
  @JsonSubTypes.Type(value = Banana.class, name = "BananaRequest")   // <-- not any more
})

@Generated(value = "org.openapitools.codegen.languages.SpringCodegen", comments = "Generator version: 7.13.0-SNAPSHOT")
public interface Fruit {

Since fruitType is marked as ignored it will not be passed from client's DTO to the request and simpleClassName will be used which will not match on server side.
If we remove that JsonIgnoreProperties then both, the explicit discriminator property value and simpleClassName will be sent to server as fruitType and again, fail on deserialization.

Only think that worked for me was to also specify

@JsonTypeInfo(
use = Id.NAME,
include = As.EXISTING_PROPERTY,
property = "fruitType",
visible = true
)

that results in:

// no more @JsonIgnoreProperties
@JsonTypeInfo(
    use = Id.NAME,
    include = As.EXISTING_PROPERTY,
    property = "fruitType",
    visible = true
)
@JsonSubTypes({
  @JsonSubTypes.Type(value = Apple.class, name = "APPLE"),
  @JsonSubTypes.Type(value = Banana.class, name = "BANANA"),
})

@Generated(value = "org.openapitools.codegen.languages.SpringCodegen", comments = "Generator version: 7.13.0-SNAPSHOT")
public interface Fruit {

then its working correctly with only explicit discriminator mapping in parent interface.

There is also workaround for this issue, to define inside openapi.yml also mapping for simpleClassName

e.g.

    FruitRequest:
      discriminator:
        mapping:
          APPLE: '#/components/schemas/AppleRequest'
          BANANA: '#/components/schemas/BananaRequest'
          AppleRequest: '#/components/schemas/AppleRequest'
          BananaRequest: '#/components/schemas/BananaRequest'

I don't kwow if possible change in https://github.com/OpenAPITools/openapi-generator/blob/master/modules/openapi-generator/src/main/resources/JavaSpring/typeInfoAnnotation.mustache would break anything else, but at least some options to enable old behavior would be greatly appreciated :-)

[Picazsoo]

In my case with java spring codegen and your linked open api spec, this happens:
Fruit:

package com.redacted.model;

import java.net.URI;
import java.util.Objects;
import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.annotation.JsonCreator;
import com.fasterxml.jackson.annotation.JsonSubTypes;
import com.fasterxml.jackson.annotation.JsonTypeInfo;
import com.fasterxml.jackson.annotation.JsonValue;
import com.redacted.model.Apple;
import com.redacted.model.Banana;
import com.redacted.model.FruitType;
import org.springframework.lang.Nullable;
import java.time.OffsetDateTime;
import jakarta.validation.Valid;
import jakarta.validation.constraints.*;
import io.swagger.v3.oas.annotations.media.Schema;


import java.util.*;
import jakarta.annotation.Generated;


@JsonIgnoreProperties(
  value = "fruitType", // ignore manually set fruitType, it will be automatically generated by Jackson during serialization
  allowSetters = true // allows the fruitType to be set during deserialization
)
@JsonTypeInfo(use = JsonTypeInfo.Id.NAME, include = JsonTypeInfo.As.PROPERTY, property = "fruitType", visible = true)
@JsonSubTypes({
  @JsonSubTypes.Type(value = Apple.class, name = "APPLE"),
  @JsonSubTypes.Type(value = Banana.class, name = "BANANA")
})

@Generated(value = "org.openapitools.codegen.languages.SpringCodegen", comments = "Generator version: 7.19.0")
public sealed interface Fruit permits Apple, Banana {
    public FruitType getFruitType();
}

Apple:

package com.redacted.model;

import java.net.URI;
import java.util.Objects;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.annotation.JsonCreator;
import org.springframework.lang.Nullable;
import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
import com.fasterxml.jackson.annotation.JsonSubTypes;
import com.fasterxml.jackson.annotation.JsonTypeInfo;
import com.fasterxml.jackson.annotation.JsonValue;
import java.time.OffsetDateTime;
import jakarta.validation.Valid;
import jakarta.validation.constraints.*;
import io.swagger.v3.oas.annotations.media.Schema;


import java.util.*;
import jakarta.annotation.Generated;

/**
 * Apple
 */
@lombok.NoArgsConstructor
@lombok.AllArgsConstructor
@lombok.experimental.SuperBuilder(toBuilder = true)

@Generated(value = "org.openapitools.codegen.languages.SpringCodegen", comments = "Generator version: 7.19.0")
public final class Apple implements Fruit {

  private Integer seeds;

  private FruitType fruitType;

  public Apple seeds(Integer seeds) {
    this.seeds = seeds;
    return this;
  }

  /**
   * Get seeds
   * @return seeds
   */
  @NotNull 
  @Schema(name = "seeds", requiredMode = Schema.RequiredMode.REQUIRED)
  @JsonProperty("seeds")
  public Integer getSeeds() {
    return seeds;
  }

  public void setSeeds(Integer seeds) {
    this.seeds = seeds;
  }

  public Apple fruitType(FruitType fruitType) {
    this.fruitType = fruitType;
    return this;
  }

  /**
   * Get fruitType
   * @return fruitType
   */
  @NotNull @Valid 
  @Schema(name = "fruitType", requiredMode = Schema.RequiredMode.REQUIRED)
  @JsonProperty("fruitType")
  public FruitType getFruitType() {
    return fruitType;
  }

  public void setFruitType(FruitType fruitType) {
    this.fruitType = fruitType;
  }

  @Override
  public boolean equals(Object o) {
    if (this == o) {
      return true;
    }
    if (o == null || getClass() != o.getClass()) {
      return false;
    }
    Apple apple = (Apple) o;
    return Objects.equals(this.seeds, apple.seeds) &&
        Objects.equals(this.fruitType, apple.fruitType);
  }

  @Override
  public int hashCode() {
    return Objects.hash(seeds, fruitType);
  }

  @Override
  public String toString() {
    StringBuilder sb = new StringBuilder();
    sb.append("class Apple {\n");
    sb.append("    seeds: ").append(toIndentedString(seeds)).append("\n");
    sb.append("    fruitType: ").append(toIndentedString(fruitType)).append("\n");
    sb.append("}");
    return sb.toString();
  }

  /**
   * Convert the given object to string with each line indented by 4 spaces
   * (except the first line).
   */
  private String toIndentedString(@Nullable Object o) {
    if (o == null) {
      return "null";
    }
    return o.toString().replace("\n", "\n    ");
  }
}

Banana:

package com.redacted.model;

import java.net.URI;
import java.util.Objects;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.annotation.JsonCreator;
import org.springframework.lang.Nullable;
import com.fasterxml.jackson.annotation.JsonIgnoreProperties;
import com.fasterxml.jackson.annotation.JsonSubTypes;
import com.fasterxml.jackson.annotation.JsonTypeInfo;
import com.fasterxml.jackson.annotation.JsonValue;
import java.time.OffsetDateTime;
import jakarta.validation.Valid;
import jakarta.validation.constraints.*;
import io.swagger.v3.oas.annotations.media.Schema;


import java.util.*;
import jakarta.annotation.Generated;

/**
 * Banana
 */
@lombok.NoArgsConstructor
@lombok.AllArgsConstructor
@lombok.experimental.SuperBuilder(toBuilder = true)

@Generated(value = "org.openapitools.codegen.languages.SpringCodegen", comments = "Generator version: 7.19.0")
public final class Banana implements Fruit {

  private Integer length;

  private FruitType fruitType;

  public Banana length(Integer length) {
    this.length = length;
    return this;
  }

  /**
   * Get length
   * @return length
   */
  @NotNull 
  @Schema(name = "length", requiredMode = Schema.RequiredMode.REQUIRED)
  @JsonProperty("length")
  public Integer getLength() {
    return length;
  }

  public void setLength(Integer length) {
    this.length = length;
  }

  public Banana fruitType(FruitType fruitType) {
    this.fruitType = fruitType;
    return this;
  }

  /**
   * Get fruitType
   * @return fruitType
   */
  @NotNull @Valid 
  @Schema(name = "fruitType", requiredMode = Schema.RequiredMode.REQUIRED)
  @JsonProperty("fruitType")
  public FruitType getFruitType() {
    return fruitType;
  }

  public void setFruitType(FruitType fruitType) {
    this.fruitType = fruitType;
  }

  @Override
  public boolean equals(Object o) {
    if (this == o) {
      return true;
    }
    if (o == null || getClass() != o.getClass()) {
      return false;
    }
    Banana banana = (Banana) o;
    return Objects.equals(this.length, banana.length) &&
        Objects.equals(this.fruitType, banana.fruitType);
  }

  @Override
  public int hashCode() {
    return Objects.hash(length, fruitType);
  }

  @Override
  public String toString() {
    StringBuilder sb = new StringBuilder();
    sb.append("class Banana {\n");
    sb.append("    length: ").append(toIndentedString(length)).append("\n");
    sb.append("    fruitType: ").append(toIndentedString(fruitType)).append("\n");
    sb.append("}");
    return sb.toString();
  }

  /**
   * Convert the given object to string with each line indented by 4 spaces
   * (except the first line).
   */
  private String toIndentedString(@Nullable Object o) {
    if (o == null) {
      return "null";
    }
    return o.toString().replace("\n", "\n    ");
  }
}

And a passing test for serialization/deserialization:

    @Test
    @DisplayName("Test serialization and deserialization of Fruit polymorphic types")
    void testSerializationDeserialization() throws JsonProcessingException {
        Apple apple = new Apple();
        apple.seeds(45);
        String serializedApple = objectMapper.writeValueAsString(apple);
        System.out.println(serializedApple); //prints {"fruitType":"APPLE","seeds":45}
        Fruit deserialized = objectMapper.readValue(serializedApple, Fruit.class);
        assertTrue("should be deserialized as Apple", deserialized instanceof Apple);
        assertFalse("should not deserialized as Banana", deserialized instanceof Banana);
    }

My understanding is that for you the deserialization to Apple class would fail because of the missing discriminator type?

[Picazsoo]

the above was generated with

    configOptions.set(
        mapOf(
            "dateLibrary" to "java8",
            "library" to "spring-boot",
            "useSealed" to "true", // set to true
            "useSpringBoot3" to "true",
            "reactive" to "true",
            "skipDefaultInterface" to "true",
            "interfaceOnly" to "true",
            "legacyDiscriminatorBehavior" to "true", // Removes class names as values for discriminator
            "openApiNullable" to "false",
            "additionalModelTypeAnnotations" to """
                @lombok.NoArgsConstructor
                @lombok.AllArgsConstructor
                @lombok.experimental.SuperBuilder(toBuilder = true)""".trimIndent(),
        )
    )

but it works also with

    configOptions.set(
        mapOf(
            "dateLibrary" to "java8",
            "library" to "spring-boot",
            "useSealed" to "false", // set to false
            "useSpringBoot3" to "true",
            "reactive" to "true",
            "skipDefaultInterface" to "true",
            "interfaceOnly" to "true",
            "legacyDiscriminatorBehavior" to "false", // set to false
            "openApiNullable" to "false",
            "additionalModelTypeAnnotations" to """
                @lombok.NoArgsConstructor
                @lombok.AllArgsConstructor
                @lombok.experimental.SuperBuilder(toBuilder = true)""".trimIndent(),
        )
    )

[GooDer]

Hi, our configuration for maven plugin is:

For shared model between server and client

                        <execution>
                            <id>generate-models</id>
                            <phase>generate-sources</phase>
                            <goals>
                                <goal>generate</goal>
                            </goals>
                            <configuration>
                            
                                <!-- OpenAPI specification file -->
                                <inputSpec>${project.basedir}/src/main/resources/open-api/api.yaml</inputSpec>

                                <!-- Use Spring generator to get full Bean Validation and Swagger annotations -->
                                <generatorName>spring</generatorName>
                                <library>spring-boot</library>

                                <!-- Output directory for generated model sources -->
                                <output>${project.build.directory}/generated-sources/openapi-models</output>

                                <!-- Shared package for all generated DTO models -->
                                <modelPackage>${main-package-name}.rest.model</modelPackage>
                                <modelNameSuffix>Dto</modelNameSuffix>

                                <!-- Generate MODELS ONLY -->
                                <globalProperties>
                                    <models/>
                                    <modelTests>false</modelTests>
                                    <modelDocs>false</modelDocs>
                              
                                    <apis>false</apis>
                                    <apiTests>false</apiTests>
                                    <apiDocs>false</apiDocs>
                              
                                    <supportingFiles>false</supportingFiles>
                                </globalProperties>
                                
                                <configOptions>
                                
                                    <!-- Spring Boot 3 uses Jakarta namespaces -->
                                    <useSpringBoot3>true</useSpringBoot3>
                                    <useJakartaEe>true</useJakartaEe>
                              
                                    <!-- Enable Bean Validation annotations (@NotNull, @Email, @Size, ...) -->
                                    <useBeanValidation>true</useBeanValidation>
                              
                                    <!-- Enable Swagger/OpenAPI annotations (@Schema) -->
                                    <annotationLibrary>swagger2</annotationLibrary>
                                    
                                    <!-- Make generated models implement java.io.Serializable -->
                                    <serializableModel>true</serializableModel>
                              
                                    <!-- Disable OpenAPI nullable wrappers -->
                                    <openApiNullable>false</openApiNullable>
                              
                                    <!-- Hide generation timestamp in generated files -->
                                    <hideGenerationTimestamp>true</hideGenerationTimestamp>
                              
                                    <!-- Use java.time API -->
                                    <dateLibrary>java8</dateLibrary>
                              
                                    <!-- Generate mutable models with fluent setters -->
                                    <modelMutable>true</modelMutable>
                                </configOptions>
....

for server:

                        <execution>
                            <id>generate-api</id>
                            <phase>generate-sources</phase>
                            <goals>
                                <goal>generate</goal>
                            </goals>
                            <configuration>
                            
                                <!-- OpenAPI specification file -->
                                <inputSpec>${project.basedir}/src/main/resources/open-api/api.yaml</inputSpec>
                                
                                <!-- Spring server generator -->
                                <generatorName>spring</generatorName>
                                <library>spring-boot</library>

                                <!-- Output directory for generated server sources -->    
                                <output>${project.build.directory}/generated-sources/openapi-server</output>

                                <!-- API package for controllers/interfaces -->
                                <apiPackage>${main-package-name}.rest.server.api</apiPackage>
                                
                                <!-- Shared models package + suffixes -->
                                <modelPackage>${main-package-name}.rest.model</modelPackage>
                                <modelNameSuffix>Dto</modelNameSuffix>
                                <apiNameSuffix>Api</apiNameSuffix>

                                <!-- IMPORTANT: do NOT generate models here -->
                                <globalProperties>
                                    <apis/>
                                    <apiTests>false</apiTests>
                                    <apiDocs>false</apiDocs>
                                    
                                    <models>false</models>
                                    <modelTests>false</modelTests>
                                    <modelDocs>false</modelDocs>
                                    
                                    <supportingFiles/>
                                </globalProperties>

                                <configOptions>
                                
                                    <!-- Spring Boot 3 / Jakarta -->
                                    <useSpringBoot3>true</useSpringBoot3>
                                    <useJakartaEe>true</useJakartaEe>
                                    <basePackage>${main-package-name}</basePackage>
                                    
                                    <!-- Group APIs by tags -->
                                    <useTags>true</useTags>
                                                                        
                                    <!-- Generator settigs -->
                                    <interfaceOnly>true</interfaceOnly>
                                    <skipDefaultInterface>true</skipDefaultInterface>

                                    <openApiNullable>false</openApiNullable>
                                    <containerDefaultToNull>true</containerDefaultToNull>
                                    <returnResponse>true</returnResponse>

                                    <virtualService>false</virtualService>
                                    <hideGenerationTimestamp>true</hideGenerationTimestamp>
                                    
                                     <!-- Hide generation timestamp in generated files -->
                                    <hideGenerationTimestamp>true</hideGenerationTimestamp>
                              
                                    <!-- Use java.time API -->
                                    <dateLibrary>java8</dateLibrary>
                                </configOptions>
....

for client

                       <execution>
                            <id>generate-client</id>
                            <phase>generate-sources</phase>
                            <goals>
                                <goal>generate</goal>
                            </goals>
                            <configuration>
                                
                                <!-- OpenAPI specification file -->
                                <inputSpec>${project.basedir}/src/main/resources/open-api/api.yaml</inputSpec>
                                
                                <!-- Java client generator using RestTemplate -->
                                <generatorName>java</generatorName>
                                <library>resttemplate</library>

                                <!-- Output directory for generated client sources -->  
                                <output>${project.build.directory}/generated-sources/openapi-client</output>

                                <!-- API package for client interfaces -->    
                                <apiPackage>${main-package-name}.rest.client.api</apiPackage>
                                
                                <!-- Shared models package + suffixes -->
                                <modelPackage>${main-package-name}.rest.model</modelPackage>
                                <invokerPackage>${main-package-name}.rest.client.invoker</invokerPackage>
                                <modelNameSuffix>Dto</modelNameSuffix>
                                <apiNameSuffix>Api</apiNameSuffix>

                                <!-- IMPORTANT: do NOT generate models here -->
                                <globalProperties>
                                    <apis/>
                                    <apiTests>false</apiTests>
                                    <apiDocs>false</apiDocs>
                                    
                                    <models>false</models>
                                    <modelTests>false</modelTests>
                                    <modelDocs>false</modelDocs>
                                    
                                    <supportingFiles/>
                                </globalProperties>

                                <configOptions>
                                
                                    <!-- Use Jakarta namespaces -->
                                    <useJakartaEe>true</useJakartaEe>
                              
                                    <!-- Generate interfaces only -->
                                    <interfaceOnly>true</interfaceOnly>
                              
                                    <!-- Group APIs by tags -->
                                    <useTags>true</useTags>
                              
                                    <!-- Use java.time API -->
                                    <dateLibrary>java8</dateLibrary>
                              
                                    <!-- Use abstraction for file uploads (Resource instead of File for params) -->
                                    <useAbstractionForFiles>true</useAbstractionForFiles>

                                </configOptions>
.....

I will try to prepare some minimalistic example this evening

[Picazsoo]

Just to confirm - the test I showed passing for me would fail for you?

[GooDer]

I will try to verify this also this evening

[Picazsoo]

ping @GooDer . We are in the very same timezone (-:

[GooDer]

You got me there. I wasn't able to force myself to work on it yesterday. I hope I will find more strength over the weekend ;-)