NPE thrown in AnnotationUtils due to "API backwards compatibility fix" introduced in 2.2.21

[joloto]

Changes introduced for this issue #4196 introduce NullPointerException due to 'API backwards compatibility' fix in which null is passed to the modified method.

The changes were introduced in this PR: #4608

This results in NPE on line 1387 of AnnotationUtils due to null components:

https://github.com/swagger-api/swagger-core/blob/d5c37284f5dbb9b6e65858c25d55c1aa2969f8a2/modules/swagger-core/src/main/java/io/swagger/v3/core/util/AnnotationsUtils.java#L1387C58-L1387C58

(I experienced this issue when upgrading springdoc-openapi from 2.4.0 -> v2.5.0, which includes upgrade to swagger-core 2.2.21, which it seems is in fact not backwards compatible!)

[frantuma]

Thanks for reporting this. Can you please share the stack trace and ideally a test case reproducing the issue?

[joloto]

Hello,

below is the stack trace.

This error occurred after updating springdoc-openapi from 2.4.0 -> v2.5.0, not directly invoking swagger ourselves. But I will try to create a small sample project that reproduces the error and will respond again here.

[joloto]

here is a small demo spring boot app created with Spring Initializr.
demo.zip

It uses springdoc-openapi 2.5.0 which includes swagger-core 2.2.21.

The test ApiDocsTest fails with the aforementioned NullPointerException
(also demonstrated when manually attempting to load the swagger or api-docs endpoints in the browser when running the application).

Everything works when reverting to swagger-core v2.2.20

The problem appears to be with the processing of response headers.

[frantuma]

fixed in #4650