Drop a constant from Servlet package in OrderedHiddenHttpMethodFilter

[izeye]

The constant comes from Servlet package and has a value of 0, so this PR simply drops the constant.

[snicoll]

Thanks again for the PR. I am not sure about this one, I've added a comment.

[snicoll]

I can understand why you'd want to drop a reference to this class but I am not sure copy/pasting the default (I mean 0) is something we want to do. Perhaps we need a shared context for this?

WDYT?

[izeye]

@snicoll Thanks for the quick feedback! I thought the same thing but couldn't find a good place to move them. So I considered adding a constant container class like FilterOrders but with only one member, I wasn't sure it's okay. Any suggestion?

[snicoll]

@bclozel that was added as part of #14008 - Does the constant has to be the same for reactive? If it's the same then we should probably need some concept that gathers them. What do you think?

[snicoll]

This should be applied to 2.0.x as well.

[philwebb]

I think for 2.0.x we should just drop the reference and hard code 0 but it feels like we're missing something from the code. The constant was originally added in 1.3 (see #3613) but looking again I wonder if we should move it out of FilterRegistrationBean. It really feels quite specific to be in there.

I wonder if adding an OrderedFilter interface might be useful? We could add one in org.springframework.boot.web.servlet.filter which extended Ordered and Filter and another in org.springframework.boot.web.reactive.filter that extends Ordered and WebFilter. I don't think there's currently a need for a common constant. I think I'd rather copy/paste than introduce another package.

[izeye]

This looks resolved via 3ff20b2, so we can close this PR unless there needs to discuss more on this.

[philwebb]

It might be worth still considering the OrderedFilter idea. Although we should probably open a different issue for that.

[philwebb]

Closing in favor of #14793