Is the compat dependency necessary?

[Fuco1]

The compat dependency seems a bit broken, let me explain.

I'm using Emacs 26.3 and the latest version of that package somehow (I don't know how) defines function json-parse-string but does not also define the function json-parse-buffer.

The lsp-mode package checks for existence of json-parse-string to use the native json parsing. However, loading no-littering which loads compat breaks my Emacs environment, because suddenly only some functions from the json-parse-* family are available. See also the upstream issue emacs-lsp/lsp-mode#3536

I've went through the code of this package and I don't see why the compat dependency is necessary. Should we consider dropping it?

[tarsius]

I'm using Emacs 26.3 and the latest version of that package somehow (I don't know how) defines function json-parse-string but does not also define the function json-parse-buffer.

If you haven't done so yet, you should report that to compat's maintainer. Maybe he can make a change or maybe he can provide some guidance on how and why lsp-mode should adjust its check.

I've went through the code of this package and I don't see why the compat dependency is necessary. Should we consider dropping it?

Some of my most popular packages definitely need compat now. I figure that means that nearly all of the users of my less popular packages already have compat installed. I have decided to add compat as a dependency of all of my packages that I still have installed myself. Most of them really do need compat, a handful do not. I have done it anyway because then I can just use the functions that I know to be provided by compat without every time having to scroll to the beginning of the file to see whether compat is already required in that particular library/package.

It also makes it easier for other package maintainers to use compat if users already have it installed because I added it as a dependency. The "I don't want to install an additional, and in my case actually unnecessary, package just for your package" argument won't work anymore if some other package already "forced" them to install it. Though admittedly magit plays a much bigger role here than no-littering. compat makes the lifes of maintainers easier and sometimes doing something just for the benefit of maintainers is okay too (though the one user, who gave me a lot of shit when I dared to add dash as a dependency of magit, would probably disagree 🤷).

[Fuco1]

Definitely agree with using dependencies and code reuse, that's the point. I was just a little worried about the compat package looking a little bit broken. I was going through the sources and honestly don't understand what it does and/or how :D

If this is in magit then I have no luck, because I would gladly exchange all other packages just to have magit 👍

I'm also trying to report this upstream, so we'll see. Given the fact compat is included in magit, we can close this discussion here.