About locate-library and locating package files with Straight

[galdor]

I have a package who must be able to discover the path of a file that is located in the same directory as the one of a library in the package. My first instinct would be to look it up in (file-name-directory (locate-library "<my-library>")). But with Straight, I obtain a directory in $HOME/.emacs.d/straight/build/<my-package>.

Is there a portable way (not Straight only, since I don't want to refer to Straight functions in a package that must be installable by people who do not use Straight) to get the original path?

A hack would be to check if the path returned by locate-library is a symlink, and if yes resolve it, but I cannot stop thinking that I'm missing something.

Hopefully someone already had this issue before.

[raxod502]

If the files are necessary for your package to function, it makes sense to put them in the :files specification, to ensure that they are also linked to the build directory. This would also be needed to make it so that when your package is installed via MELPA (using package.el, say) those files are still available. In that case, (file-name-directory (locate-library ...)) will give you what you want.

[galdor]

But does it mean that I would have to tell potential users to manually remember to set :files to a specific value when using the package? I was hoping the Emacs packaging system would have a way to deal with it, but I'm just realizing how limited it is and how much Straight has to do by itself.

[raxod502]

Well, how are you distributing the package? If it's listed on MELPA, then your submission to MELPA is a recipe that tells them which repository your package is located in. That recipe also includes a :files directive, which everyone will use by default. That will apply to both package.el and straight.el.

[galdor]

But I have no reason to use MELPA (I stopped publishing to MELPA due to their frustrating review rules). Emacs (and Straight, and other package managers) lets people install packages from arbitrary repositories. This kind of metadata (a list of files to includes in builds) should be part of the package, not of the recipe people have to use to install it.

I understand if it is impossible for the moment, I'll deal with the symlink to find the original library file and then the parent directory, and then the data file, but it still is strange that there is no standard way to deal with data files in installed packages.

[raxod502]

I mean, the standard way is to list the package in one of the official registries, like MELPA. That way, people don't have to know the URL of the repository, they can just find the package by name. If you don't want to do that, then yeah, you would have to provide the same information to users manually.