[BUG] type: array is not taken into account when content is multipart/form-data

Description

type: array is not taken into account when content is multipart/form-data

generated java code:

@ApiOperation(value = "upload files", nickname = "uploadFiles", notes = "", response = UploadActionStatus.class, tags={  })
@ApiResponses(value = { 
    @ApiResponse(code = 200, message = "files upload status", response = UploadActionStatus.class),
    @ApiResponse(code = 200, message = "unexpected error", response = Error.class) })
@RequestMapping(value = "/utility/upload",
    produces = { "application/json" }, 
    consumes = { "multipart/form-data" },
    method = RequestMethod.POST)
default ResponseEntity<UploadActionStatus> _uploadFiles(@ApiParam(value = "file detail") @Valid @RequestPart("file") MultipartFile filenames) {
    return uploadFiles(filenames);
}

Expected:

@ApiOperation(value = "upload files", nickname = "uploadFiles", notes = "", response = UploadActionStatus.class, tags={  })
@ApiResponses(value = { 
    @ApiResponse(code = 200, message = "files upload status", response = UploadActionStatus.class),
    @ApiResponse(code = 200, message = "unexpected error", response = Error.class) })
@RequestMapping(value = "/utility/upload",
    produces = { "application/json" }, 
    consumes = { "multipart/form-data" },
    method = RequestMethod.POST)
default ResponseEntity<UploadActionStatus> _uploadFiles(@ApiParam(value = "file detail") @Valid @RequestPart("file") MultipartFile[] filenames) {
    return uploadFiles(filenames);
}

openapi-generator version

openapi-generator-maven-plugin 4.2.2

OpenAPI declaration file content or url

  requestBody:
    content:
      multipart/form-data:
        schema:
          type: object
          properties:
            filenames:
              type: array
              items:
                type: string
                format: binary

Command line used for generation

		<plugin>
			<groupId>org.openapitools</groupId>
			<artifactId>openapi-generator-maven-plugin</artifactId>
			<executions>
				<execution>
					<phase>generate-sources</phase>
					<goals>
						<goal>generate</goal>
					</goals>
					<configuration>
						<inputSpec>${project.build.directory}/integration/my.yml</inputSpec>
						<generatorName>spring</generatorName>
						<apiPackage>my..controller</apiPackage>
						<modelPackage>my..model</modelPackage>
						<generateSupportingFiles>true</generateSupportingFiles>
						<configOptions>
							<enableBuilderSupport>true</enableBuilderSupport>
							<interfaceOnly>true</interfaceOnly>
							<dateLibrary>java8</dateLibrary>
							<java8>true</java8>
							<serializableModel>true</serializableModel>
							<delegatePattern>true</delegatePattern>
							<useBeanValidation>true</useBeanValidation>
							<hideGenerationTimestamp>true</hideGenerationTimestamp>
							<simpleFluentPattern>true</simpleFluentPattern>
							<collectionFluentPattern>true</collectionFluentPattern>
						</configOptions>
					</configuration>
				</execution>
			</executions>
		</plugin>

Steps to reproduce

create java maven project and generate code

Related issues/PRs

Suggest a fix/enhancement

Expected:

filenames shall be an array:

@ApiOperation(value = "upload files", nickname = "uploadFiles", notes = "", response = UploadActionStatus.class, tags={  })
@ApiResponses(value = { 
    @ApiResponse(code = 200, message = "files upload status", response = UploadActionStatus.class),
    @ApiResponse(code = 200, message = "unexpected error", response = Error.class) })
@RequestMapping(value = "/utility/upload",
    produces = { "application/json" }, 
    consumes = { "multipart/form-data" },
    method = RequestMethod.POST)
default ResponseEntity<UploadActionStatus> _uploadFiles(@ApiParam(value = "file detail") @Valid @RequestPart("file") MultipartFile[] filenames) {
    return uploadFiles(filenames);
}

Reproduce the issue with the provided Maven configuration, OpenAPI declaration, and spring generator. Trace multipart/form-data request-body handling for an array of binary items, then verify generation produces a MultipartFile[] parameter rather than MultipartFile for the filenames field.