Aliases in parameter annotations on a controller interface are not evaluated [SPR-17460]

[spring-projects-issues]

Bogdan Zafirov opened SPR-17460 and commented

The problem is explained in this Stack Overflow answer: https://stackoverflow.com/a/8005644. As pointed out in the comment to this answer, this is "problem" is already solved in other frameworks such as Jersey.

The goal would be Spring Framework to consider/evaluate the annotations on interface methods (e.g. public void getUser(@RequestParam("user-id")), so a developer doesn't have to define the annotations in the implementing class again.

By generating a server implementation from a OAS3 contract (e.g. https://github.com/OpenAPITools/openapi-generator) one can easily face this problem, since the annotations from the generated code (a Java Interface) will not be evaluated on a HTTP call.

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Affects: 5.1.2

Attachments:

• rest-annotations.zip (69.61 kB)

Issue Links:

• Enable REST controller method parameter annotations on an interface [SPR-11055] #15682 Enable REST controller method parameter annotations on an interface

Referenced from: commits c58da71

[spring-projects-issues]

Juergen Hoeller commented

We aimed to address this in 5.1 through #15682... Could you please double-check that your case indeed does not work against 5.1.2 and ideally provide a particular case to reproduce?

[spring-projects-issues]

Bogdan Zafirov commented

Juergen Hoeller I attached an example Spring-Boot application (created with https://start.spring.io). There is one interface (TestInterface.java) and an implementing class annotated with RestController (TestController.java). When I do a HTTP GET with the following URL  http://localhost:8080/v1/test/ZZ95711905000000500000 I get 'Internal Server Error'. The error message is: "Missing URI template variable 'testId' for method parameter of type String". This actually shows that Spring is considering the variable name instead of the value set in the PathVariable (e.g. test-id) annotation. The same thing happens for the header parameter 'X-Request-ID', namely the header parameter has to named xRequestID.

[spring-projects-issues]

Juergen Hoeller commented

Brian Clozel, could you please try to debug the repro app and double-check why this still doesn't work against 5.1.x there?

[spring-projects-issues]

WiedemannA commented

Juergen Hoeller: I've got the same problem in version 5.1 and debugged the code:
The difference seems to be, that the @AliasFor-Annotation (e.g. in PathVariable) is not evaluated by the new code that takes over the interface annotations.

And the swagger-codegen (OpenApiGenerator likewise) generates interfaces in which only value is set, e.g.:
@PathVariable("test-id")

The PathVariableMethodArgumentResolver only takes over the name out of the PathVariable-Annotation.
 
Therefore the check if the name is empty in AbstractNamedValueMethodArgumentResolver.updateNamedValueInfo() delivers true and falls back to the ParameterName, which causes the error Bogdan Zafirov describes...

Bogdan Zafirov: Can you verifiy, that the Problem doesn't occure, if you set both value and name?
@PathVariable(name= "test-id", value = "test-id")

[spring-projects-issues]

Juergen Hoeller commented

WiedemannA, good catch! I was able to reproduce this; we indeed miss a synthesizeAnnotation step for interface-level annotations, not evaluating their aliases. Fixed in master now for the 5.1.3 release.