Required fields are not validated when creating a model inside an allOf

[pablogalegoc]

Describe the bug
When composing a model with allOf, the validation of required fields doesn't work if an object is defined inside that same allOf. It works if the composed model references a component model outside of it.

To Reproduce
I'm using version 1.6 of the plugin. When trying the latest 1.8 version it fails with an internal error (see Additional context section).

This doesn't fail:

components:
  schemas:
    Composition:
      allOf:
        - type: object
          required:
            - something
          properties:
            someotherthing:
              type: array
              items:
                $ref: '#/components/schemas/Another'
        - $ref: '#/components/schemas/Other'
    Other:
         type: string
         example: "Other"
    Another:
         type: string
         example: "Another"

This does fail:

components:
  schemas:
    Composition:
      type: object
      allOf:
        - $ref: '#/components/schemas/This'
        - $ref: '#/components/schemas/Other'
    This:
      type: object
      required:
        - something
      properties:
        someotherthing:
          type: array
          items:
            $ref: '#/components/schemas/Another'
    Other:
      type: string
      example: "Sample"
    Another:
         type: string
         example: "Another"

...with this error:

[ERROR] OpenAPI Specification does not meet the requirements. Issues:
[ERROR]         *ERROR* in Model 'This', property 'something' -> This property should be present or removed from the list of required

Minimal project to reproduce: test-required-fields.zip. Run mvn verify with inputFile as build-success-but-should-fail.yaml and fails-and-it-should-fail.yaml.

Expected behavior
Both of those examples should fail the validation of required fields.

Additional context
Internal error that I get in the minimal project on 1.8 version and validating build-success-but-should-fail.yaml:

[ERROR] Failed to execute goal org.openapitools.openapistylevalidator:openapi-style-validator-maven-plugin:1.8:validate (default) on project test-required-fields: Execution default of goal org.openapitools.openapistylevalidator:openapi-style-validator-maven-plugin:1.8:validate failed: An API incompatibility was encountered while executing org.openapitools.openapistylevalidator:openapi-style-validator-maven-plugin:1.8:validate: java.lang.NoSuchMethodError: 'io.swagger.v3.oas.models.media.Schema io.swagger.v3.oas.models.media.ComposedSchema.addAllOfItem(io.swagger.v3.oas.models.media.Schema)'
[ERROR] -----------------------------------------------------
[ERROR] realm =    plugin>org.openapitools.openapistylevalidator:openapi-style-validator-maven-plugin:1.8
[ERROR] strategy = org.codehaus.plexus.classworlds.strategy.SelfFirstStrategy
[ERROR] urls[0] = file:/[...]/.m2/repository/org/openapitools/openapistylevalidator/openapi-style-validator-maven-plugin/1.8/openapi-style-validator-maven-plugin-1.8.jar
[ERROR] urls[1] = file:/[...]/.m2/repository/org/openapitools/openapistylevalidator/openapi-style-validator-lib/1.8/openapi-style-validator-lib-1.8.jar
[ERROR] urls[2] = file:/[...]/.m2/repository/org/eclipse/microprofile/openapi/microprofile-openapi-api/3.0/microprofile-openapi-api-3.0.jar
[ERROR] urls[3] = file:/[...]/.m2/repository/io/swagger/parser/v3/swagger-parser/2.0.32/swagger-parser-2.0.32.jar
[ERROR] urls[4] = file:/[...]/.m2/repository/io/swagger/parser/v3/swagger-parser-v2-converter/2.0.32/swagger-parser-v2-converter-2.0.32.jar
[ERROR] urls[5] = file:/[...]/.m2/repository/io/swagger/swagger-core/1.6.6/swagger-core-1.6.6.jar
[ERROR] urls[6] = file:/[...]/.m2/repository/io/swagger/swagger-models/1.6.6/swagger-models-1.6.6.jar
[ERROR] urls[7] = file:/[...]/.m2/repository/io/swagger/swagger-annotations/1.6.6/swagger-annotations-1.6.6.jar
[ERROR] urls[8] = file:/[...]/.m2/repository/com/google/guava/guava/31.0.1-android/guava-31.0.1-android.jar
[ERROR] urls[9] = file:/[...]/.m2/repository/com/google/guava/failureaccess/1.0.1/failureaccess-1.0.1.jar
[ERROR] urls[10] = file:/[...]/.m2/repository/com/google/guava/listenablefuture/9999.0-empty-to-avoid-conflict-with-guava/listenablefuture-9999.0-empty-to-avoid-conflict-with-guava.jar
[ERROR] urls[11] = file:/[...]/.m2/repository/com/google/code/findbugs/jsr305/3.0.2/jsr305-3.0.2.jar
[ERROR] urls[12] = file:/[...]/.m2/repository/org/checkerframework/checker-qual/3.12.0/checker-qual-3.12.0.jar
[ERROR] urls[13] = file:/[...]/.m2/repository/org/checkerframework/checker-compat-qual/2.5.5/checker-compat-qual-2.5.5.jar
[ERROR] urls[14] = file:/[...]/.m2/repository/com/google/errorprone/error_prone_annotations/2.7.1/error_prone_annotations-2.7.1.jar
[ERROR] urls[15] = file:/[...]/.m2/repository/com/google/j2objc/j2objc-annotations/1.3/j2objc-annotations-1.3.jar
[ERROR] urls[16] = file:/[...]/.m2/repository/javax/validation/validation-api/1.1.0.Final/validation-api-1.1.0.Final.jar
[ERROR] urls[17] = file:/[...]/.m2/repository/io/swagger/swagger-parser/1.0.59/swagger-parser-1.0.59.jar
[ERROR] urls[18] = file:/[...]/.m2/repository/io/swagger/swagger-compat-spec-parser/1.0.59/swagger-compat-spec-parser-1.0.59.jar
[ERROR] urls[19] = file:/[...]/.m2/repository/com/github/java-json-tools/json-schema-validator/2.2.14/json-schema-validator-2.2.14.jar
[ERROR] urls[20] = file:/[...]/.m2/repository/com/github/java-json-tools/jackson-coreutils-equivalence/1.0/jackson-coreutils-equivalence-1.0.jar
[ERROR] urls[21] = file:/[...]/.m2/repository/com/github/java-json-tools/json-schema-core/1.2.14/json-schema-core-1.2.14.jar
[ERROR] urls[22] = file:/[...]/.m2/repository/com/github/java-json-tools/uri-template/0.10/uri-template-0.10.jar
[ERROR] urls[23] = file:/[...]/.m2/repository/org/mozilla/rhino/1.7.7.2/rhino-1.7.7.2.jar
[ERROR] urls[24] = file:/[...]/.m2/repository/com/sun/mail/mailapi/1.6.2/mailapi-1.6.2.jar
[ERROR] urls[25] = file:/[...]/.m2/repository/joda-time/joda-time/2.10.5/joda-time-2.10.5.jar
[ERROR] urls[26] = file:/[...]/.m2/repository/com/googlecode/libphonenumber/libphonenumber/8.11.1/libphonenumber-8.11.1.jar
[ERROR] urls[27] = file:/[...]/.m2/repository/net/sf/jopt-simple/jopt-simple/5.0.4/jopt-simple-5.0.4.jar
[ERROR] urls[28] = file:/[...]/.m2/repository/com/github/java-json-tools/json-patch/1.13/json-patch-1.13.jar
[ERROR] urls[29] = file:/[...]/.m2/repository/com/github/java-json-tools/msg-simple/1.2/msg-simple-1.2.jar
[ERROR] urls[30] = file:/[...]/.m2/repository/com/github/java-json-tools/btf/1.3/btf-1.3.jar
[ERROR] urls[31] = file:/[...]/.m2/repository/com/github/java-json-tools/jackson-coreutils/2.0/jackson-coreutils-2.0.jar
[ERROR] urls[32] = file:/[...]/.m2/repository/org/apache/httpcomponents/httpclient/4.5.13/httpclient-4.5.13.jar
[ERROR] urls[33] = file:/[...]/.m2/repository/org/apache/httpcomponents/httpcore/4.4.13/httpcore-4.4.13.jar
[ERROR] urls[34] = file:/[...]/.m2/repository/commons-logging/commons-logging/1.2/commons-logging-1.2.jar
[ERROR] urls[35] = file:/[...]/.m2/repository/commons-codec/commons-codec/1.11/commons-codec-1.11.jar
[ERROR] urls[36] = file:/[...]/.m2/repository/io/swagger/parser/v3/swagger-parser-core/2.0.32/swagger-parser-core-2.0.32.jar
[ERROR] urls[37] = file:/[...]/.m2/repository/io/swagger/parser/v3/swagger-parser-v3/2.0.32/swagger-parser-v3-2.0.32.jar
[ERROR] urls[38] = file:/[...]/.m2/repository/io/swagger/core/v3/swagger-core/2.2.0/swagger-core-2.2.0.jar
[ERROR] urls[39] = file:/[...]/.m2/repository/jakarta/xml/bind/jakarta.xml.bind-api/2.3.2/jakarta.xml.bind-api-2.3.2.jar
[ERROR] urls[40] = file:/[...]/.m2/repository/jakarta/activation/jakarta.activation-api/1.2.1/jakarta.activation-api-1.2.1.jar
[ERROR] urls[41] = file:/[...]/.m2/repository/com/fasterxml/jackson/datatype/jackson-datatype-jsr310/2.13.2/jackson-datatype-jsr310-2.13.2.jar
[ERROR] urls[42] = file:/[...]/.m2/repository/io/swagger/core/v3/swagger-annotations/2.2.0/swagger-annotations-2.2.0.jar
[ERROR] urls[43] = file:/[...]/.m2/repository/jakarta/validation/jakarta.validation-api/2.0.2/jakarta.validation-api-2.0.2.jar
[ERROR] urls[44] = file:/[...]/.m2/repository/com/fasterxml/jackson/core/jackson-annotations/2.13.2/jackson-annotations-2.13.2.jar
[ERROR] urls[45] = file:/[...]/.m2/repository/com/fasterxml/jackson/core/jackson-databind/2.13.2.2/jackson-databind-2.13.2.2.jar
[ERROR] urls[46] = file:/[...]/.m2/repository/com/fasterxml/jackson/core/jackson-core/2.13.2/jackson-core-2.13.2.jar
[ERROR] urls[47] = file:/[...]/.m2/repository/com/fasterxml/jackson/dataformat/jackson-dataformat-yaml/2.13.2/jackson-dataformat-yaml-2.13.2.jar
[ERROR] urls[48] = file:/[...]/.m2/repository/org/yaml/snakeyaml/1.30/snakeyaml-1.30.jar
[ERROR] urls[49] = file:/[...]/.m2/repository/commons-io/commons-io/2.11.0/commons-io-2.11.0.jar
[ERROR] urls[50] = file:/[...]/.m2/repository/org/openapitools/empoa/empoa-swagger-core/2.0.0/empoa-swagger-core-2.0.0.jar
[ERROR] urls[51] = file:/[...]/.m2/repository/io/swagger/core/v3/swagger-models/2.1.2/swagger-models-2.1.2.jar
[ERROR] urls[52] = file:/[...]/.m2/repository/org/apache/commons/commons-lang3/3.8.1/commons-lang3-3.8.1.jar
[ERROR] urls[53] = file:/[...]/.m2/repository/org/eclipse/sisu/org.eclipse.sisu.inject/0.3.5/org.eclipse.sisu.inject-0.3.5.jar
[ERROR] urls[54] = file:/[...]/.m2/repository/org/codehaus/plexus/plexus-component-annotations/1.5.5/plexus-component-annotations-1.5.5.jar
[ERROR] urls[55] = file:/[...]/.m2/repository/org/codehaus/plexus/plexus-utils/3.3.0/plexus-utils-3.3.0.jar
[ERROR] Number of foreign imports: 1
[ERROR] import: Entry[import  from realm ClassRealm[maven.api, parent: null]]

[JFCote]

@pablogalegoc Thanks for the bug report! If you think you can provide a PR for this fix, please don't hesitate and I will review it!