[BUG] No argument constructor missing

Bug Report Checklist

• Have you provided a full/minimal spec to reproduce the issue?
• Have you validated the input using an OpenAPI validator (example)?
• Have you tested with the latest master to confirm the issue still exists?
• Have you searched for related issues/PRs?
• What's the actual output vs expected output?

Description

The generator missing the no argument constructor when x-class-extra-annotation is used. If we add any required properties the no argument constructor is created but when the object does not have any required field the no argument constructor won't be generated.

openapi-generator version

7.7.0

OpenAPI declaration file content or url

    myModelObject:
      x-class-extra-annotation: |
        @lombok.AllArgsConstructor
        @lombok.Builder
      type: object
      properties:
        firstField:
          description: 'it is field one'
          type: number
          format: double
          example: 30000
        secondField:
          description: 'it is field two'
          type: number
          format: double
          example: 30000

Generation Details

<plugin>
    <groupId>org.openapitools</groupId>
    <artifactId>openapi-generator-maven-plugin</artifactId>
    <version>${openapi.maven.plugin.version}</version>
    <executions>
        <execution>
            <id>generate-client</id>
            <goals>
                <goal>generate</goal>
            </goals>
            <configuration>
                <inputSpec>
                    ${project.basedir}/src/main/resources/xxx_api.yml
                </inputSpec>
                <generatorName>spring</generatorName>
                <apiPackage>...</apiPackage>
                <modelPackage>...</modelPackage>
                <configOptions>
                    <useSpringBoot3>true</useSpringBoot3>
                    <reactive>true</reactive>
                    <useResponseEntity>false</useResponseEntity>
                    <useJakartaEe>true</useJakartaEe>
                    <interfaceOnly>true</interfaceOnly>
                    <additionalModelTypeAnnotations>
                        @com.fasterxml.jackson.annotation.JsonInclude(com.fasterxml.jackson.annotation.JsonInclude.Include.NON_NULL)
                    </additionalModelTypeAnnotations>
                </configOptions>
                <typeMappings>
                    <typeMapping>Double=java.math.BigDecimal</typeMapping>
                </typeMappings>
                <additionalProperties>removeEnumValuePrefix=false</additionalProperties>
            </configuration>
        </execution>
    </executions>
</plugin>

Generated Class

package com.nordea.nf.calculation.api.contract.model;

import com.fasterxml.jackson.annotation.JsonInclude;
import com.fasterxml.jackson.annotation.JsonProperty;
import com.fasterxml.jackson.annotation.JsonTypeName;
import com.fasterxml.jackson.annotation.JsonInclude.Include;
import io.swagger.v3.oas.annotations.media.Schema;
import io.swagger.v3.oas.annotations.media.Schema.RequiredMode;
import java.math.BigDecimal;
import java.util.Objects;
import lombok.Generated;

@JsonInclude(Include.NON_NULL)
@JsonTypeName("myModelObject")
public class MyModelObject {
    private BigDecimal firstField;
    private BigDecimal secondField;

    public MyModelObject firstField(BigDecimal firstField) {
        this.firstField = firstField;
        return this;
    }

    @Schema(
        name = "firstField",
        example = "30000",
        description = "it is field one",
        requiredMode = RequiredMode.NOT_REQUIRED
    )
    @JsonProperty("firstField")
    public BigDecimal getFirstField() {
        return this.firstField;
    }

    public void setFirstField(BigDecimal firstField) {
        this.firstField = firstField;
    }

    public MyModelObject secondField(BigDecimal secondField) {
        this.secondField = secondField;
        return this;
    }

    @Schema(
        name = "secondField",
        example = "30000",
        description = "it is field two",
        requiredMode = RequiredMode.NOT_REQUIRED
    )
    @JsonProperty("secondField")
    public BigDecimal getSecondField() {
        return this.secondField;
    }

    public void setSecondField(BigDecimal secondField) {
        this.secondField = secondField;
    }

    public boolean equals(Object o) {
        if (this == o) {
            return true;
        } else if (o != null && this.getClass() == o.getClass()) {
            MyModelObject myModelObject = (MyModelObject)o;
            return Objects.equals(this.firstField, myModelObject.firstField) && Objects.equals(this.secondField, myModelObject.secondField);
        } else {
            return false;
        }
    }

    public int hashCode() {
        return Objects.hash(new Object[]{this.firstField, this.secondField});
    }

    public String toString() {
        StringBuilder sb = new StringBuilder();
        sb.append("class MyModelObject {\n");
        sb.append("    firstField: ").append(this.toIndentedString(this.firstField)).append("\n");
        sb.append("    secondField: ").append(this.toIndentedString(this.secondField)).append("\n");
        sb.append("}");
        return sb.toString();
    }

    private String toIndentedString(Object o) {
        return o == null ? "null" : o.toString().replace("\n", "\n    ");
    }

    @Generated
    public static MyModelObjectBuilder builder() {
        return new MyModelObjectBuilder();
    }

    @Generated
    public MyModelObject(BigDecimal firstField, BigDecimal secondField) {
        this.firstField = firstField;
        this.secondField = secondField;
    }

    @Generated
    public static class MyModelObjectBuilder {
        @Generated
        private BigDecimal firstField;
        @Generated
        private BigDecimal secondField;

        @Generated
        MyModelObjectBuilder() {
        }

        @Generated
        public MyModelObjectBuilder firstField(BigDecimal firstField) {
            this.firstField = firstField;
            return this;
        }

        @Generated
        public MyModelObjectBuilder secondField(BigDecimal secondField) {
            this.secondField = secondField;
            return this;
        }

        @Generated
        public MyModelObject build() {
            return new MyModelObject(this.firstField, this.secondField);
        }

        @Generated
        public String toString() {
            return "MyModelObject.MyModelObjectBuilder(firstField=" + this.firstField + ", secondField=" + this.secondField + ")";
        }
    }
}

Steps to reproduce

Related issues/PRs

Suggest a fix

Start with the supplied OpenAPI declaration, Maven plugin configuration, and generated MyModelObject class. Reproduce the output with openapi-generator 7.7.0, comparing models with and without required properties, then trace the Spring generator path that renders the model. Done means a model with no required properties also has the expected no-argument constructor without regressing the required-property case.