When no API version is provided, `/error` requests also fail.

[ghoonch4]

I am experimenting with the API Versioning feature introduced in Spring 7.
When I send a request without specifying an API version, I receive an empty response body, as shown below:

~ > curl -XGET localhost:8080/foo/bar -i
HTTP/1.1 400
Content-Length: 0
Date: Sat, 20 Dec 2025 18:17:10 GMT
Connection: close

According to the following code:

https://github.com/spring-projects/spring-framework/blame/0b2bb7e751d5effd798adaf545c64a7342657ecc/spring-webmvc/src/main/java/org/springframework/web/servlet/handler/AbstractHandlerMapping.java#L542

the /foo/bar request fails in the initApiVersion(request) method.
The subsequent /error request also fails at the same point and never reaches the ErrorController, which is responsible for generating the response body.

[ghoonch4]

To add some clarification, the two issues are related, but this issue is slightly more complex than issue #36059.

Preconditions

• Only a single property is configured: spring.mvc.apiversion.use.header=X-Api-Version
• The handler code is as follows:

@GetMapping(path = ["/foo/bar"], version = "1")
fun fooBar(): String {
    return "Hello World"
}

Issue #36059

• AbstractHandlerMapping has an ApiVersionStrategy field, and its implementation, DefaultApiVersionStrategy, has a versionRequired field. This can be interpreted to mean that versionRequired can be controlled per HandlerMapping.
• However, in the current behavior, the highest-priority RouterFunctionMapping requires a version and throws an error. As a result, the request never reaches subsequent HandlerMappings that do not require a version.
• In other words, instead of versionRequired being controlled per HandlerMapping, interference occurs between different HandlerMappings, and this interference does not appear to be properly resolved.

This issue

• It shares the same issue as When no API version is provided, static resources fail to load #36059 in that errors occur due to interference from RouterFunctionMapping. Additionally, there is a further problem in that both the original request and the error dispatch request are handled by the same RequestMappingHandlerMapping.
• When RequestMappingHandlerMapping requires version information, requests without version information fail. The subsequent error dispatch request is also processed by RequestMappingHandlerMapping and fails at the same point, so it never reaches the ErrorController and cannot generate an error response body.

[AtharvUrunkar]

Hi maintainers, thanks for the clarification on this issue.

I’ve been looking into the root cause, and it appears that API version resolution is currently applied during ERROR dispatch as well. As a result, the error dispatch request fails at the same point as the original request and never reaches the ErrorController, leading to an empty response body.

A minimal fix that seems promising would be to skip API version checks for DispatcherType.ERROR, which would restore normal error handling without changing behavior for regular requests.

Before starting work on a PR, I wanted to confirm whether this approach aligns with the intended direction, or if there’s a preferred alternative the team would like to see.

Thanks!