Subject: bug#78593: 31.0.50; describe-key broken on interactive lambdas

From: Stefan Monnier <[email-masked]>
Date: Sat, 28 Jun 2025 12:00:01 -0400

> Stefan, this is due to your change:
>
>   commit a4ec9ca12969018cdf15b8cc713b3ba054326f99
>   Author:     Stefan Kangas <[email-masked]>
>   AuthorDate: Tue Apr 1 21:25:33 2025 +0200
>   Commit:     Stefan Kangas <[email-masked]>
>   CommitDate: Tue Apr 1 21:25:33 2025 +0200
>
>       function-put: signal error with non-symbol
>
>       * lisp/subr.el (function-get): Signal an error if given a non-symbol
>       for consistency with 'get'.
>       * test/lisp/subr-tests.el (subr-butlast): Test for the above.
>
> Any reasons not to revert that?  function-get correctly returns nil if
> its argument is not a symbol, so why should this signal an error?

IMO, `function-get/put` should accept *functions* as arguments, not
just symbols.

        Stefan