[BUG] warning for optional attribte spams build log with "Empty operationId found for path"

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?
• [Optional] Sponsorship to speed up the bug fix or feature request (example)

Description

Generating code from specification with many operations may lead to build-log spamming with messages like:

[WARNING] Empty operationId found for path: get /{realm}/users/count. Renamed to auto-generated operationId: realmUsersCountGet
[WARNING] Empty operationId found for path: get /{realm}/users/{id}. Renamed to auto-generated operationId: realmUsersIdGet
[WARNING] Empty operationId found for path: put /{realm}/users/{id}. Renamed to auto-generated operationId: realmUsersIdPut
[WARNING] Empty operationId found for path: delete /{realm}/users/{id}. Renamed to auto-generated operationId: realmUsersIdDelete

In the case of https://github.com/ccouzens/keycloak-openapi/blob/main/keycloak/12.0-patched.json this would be 290 Warnings.

Now operationId is an optional attribte, and omitting an optional attribute should not lead to a warning in the build log, but to either silent usage of the auto-generated operationId, or an informative log-statement or one for debugging purposes. In this case, even the log-level "debug" would spam the build-log with an extreme amount of lines.

This is why I would recommend removal of the logging statement. See https://github.com/OpenAPITools/openapi-generator/blob/master/modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultCodegen.java#L4639

openapi-generator version

5.0.1

OpenAPI declaration file content or url

https://github.com/ccouzens/keycloak-openapi/blob/main/keycloak/12.0-patched.json

Generation Details

<configuration>
    <!-- only generate api operations wih given tags -->
    <apisToGenerate>Users</apisToGenerate>
    <!-- only generate models that are referenced in generated api operations -->
    <modelsToGenerate>CredentialRepresentation,FederatedIdentityRepresentation,UserConsentRepresentation,UserRepresentation,UserSessionRepresentation,GroupRepresentation</modelsToGenerate>
    <inputSpec>${project.basedir}/src/main/resources/idp/12.0-patched.json</inputSpec>
    <generatorName>jaxrs-spec</generatorName>
    <output>${project.build.directory}/generated-sources/openapi/keycloak</output>
    <configOptions>
        <useTags>true</useTags>
        <interfaceOnly>true</interfaceOnly>
        <returnResponse>false</returnResponse>
        <sourceFolder>java</sourceFolder>
        <useSwaggerAnnotations>false</useSwaggerAnnotations>
        <generatePom>false</generatePom>
        <dateLibrary>java8</dateLibrary>
    </configOptions>
</configuration>

Steps to reproduce

Generate code from https://github.com/ccouzens/keycloak-openapi/blob/main/keycloak/12.0-patched.json
I suspect that any generator will lead to the same logging behaviour.

Related issues/PRs

Not for OpenAPI, but for swagger-codegen: https://github.com/swagger-api/swagger-codegen/issues/5162

Suggest a fix

Delete the mentioned log statement.

Start in modules/openapi-generator/src/main/java/org/openapitools/codegen/DefaultCodegen.java around line 4639, then reproduce generation with the linked Keycloak OpenAPI document or a smaller spec containing operations without operationId. Check the generator's logging behavior and relevant tests; done means omitted optional operationIds no longer produce build-log warnings while generated operationIds still work.