conditional deprecation

[dchelimsky]

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Is your feature request related to a problem? Please describe.

We have a utility function library with map-vals, that does the same thing as clojure-1.11's clojure.core/update-vals, but predates it. We have some consumers that are using clojure-1.11, but some that are using older versions. We'd like to convey to consumers using 1.11 that our home-grown map-vals is deprecated and you should use clojure.core/update-vals, but consumers using < 1.11 would not see this.

Describe the solution you'd like

Here's one idea, but I'm sure there are plenty of others that would work: add support for e.g. :deprecated {:doc "..." :replaced-by {:lib "org.clojure/clojure" :version "1.11.0"}}. This would support the idea for any library at all.

clj-kondo would have to look validate this against the project's dependencies.

Describe alternatives you've considered

The keys could be named differently, and/or could be flattened (all at top level of the metadata map)

[borkdude]

I'm converting this to a Q&A since I'm fairly sure clj-kondo already has what you need. The linter you're searching for is probably:

https://github.com/clj-kondo/clj-kondo/blob/master/doc/linters.md#discouraged-var

You can make a configuration for all of your libs which discourages your.lib/map-vals with a message.

Projects that still use clojure 1.11 can override this config in their local .clj-kondo/config.edn.

[borkdude]

I'd have to double check if you can undo discouraging in a local config. There might be an issue with that, see:

#1979

So it would be good to watch that issue.