Hi Philip,

I am on emacs versio 30.0.93. and I tried an init file like this:

;;; init.el --- -*- lexical-binding: t; -*-

(require 'package)
(package-initialize)
(package-vc-install
  '(consult-omni :url "https://github.com/armindarvish/consult-omni"
         :main-file "consult-omni.el"))

The issue we have to keep in mind is that since we add the repository
directly to `load-path', all the files can be used no matter what
"specific" file you might intend to use. To retain usability and not
have unexpected function calls fail, we rather install all the
dependencies.

My understanding was that packages are either a single-file package, which won't have this problem, or a multi-file package, in which case, the "Package-Requires: " header should only be in the main file and not the extra lisp files. As far as I know, other package managing systems (like MELPA) don't use hte "Package-Requires: " header in the files other than the main lisp file either. Note that, we can still add all the files in the repo to load-path, but when automatically making the "define-package" declaration in a "package-pkg.el" file, the dependencies should be inferred form the main file and not others, otherwise there will be weird looped dependencies. For example, in case of embark with the following init file:

;;; init.el --- -*- lexical-binding: t; -*-

(require 'package)
;; Adds the Melpa archive to the list of available repositories
 (setq package-archives
       '(("elpa" . "https://elpa.gnu.org/packages/")
         ("melpa-stable" . "https://stable.melpa.org/packages/")
         ("melpa" . "https://melpa.org/packages/")))
;; Initializes the package infrastructure
(package-initialize)
(package-refresh-contents)

(use-package embark
:vc (:url "https://github.com/oantolin/embark"))

I can see multiple versions of embark being pulled from MELPA becuase of looped depenncies in the embark-pkg.el file automatically created by package-vc-install. Here is the contents of that file:

(define-package "embark" "1.1" "No description available." '((emacs "25.1") (embark "0.9") (avy "0.5") (emacs "27.1") (compat "29.1.4.0") (embark "1.0") (consult "1.0")) :kind vc :commit "195add1f1ccd1059472c9df7334c97c4d155425e")

Note that while this installs just fine, it is pulling 3 different versions of embark from MELPA becuase of this inferred looped self-dependency from differnt *.el files in embark repo, which is not the intended behavior by the author of that package.

That said, I agree with the point that there can potentially be other solutions like terminating properly as you said or even better would be detecting and ignoring any self-dependency. I cannot think of any scenario where a package should depend on its own or on an older version of its own.

Philip Kaludercic @ 2025-02-16 18:53 :

Armin Darvish <armindarvish@gmail.com> writes:

Hello,

I have noticed that with vc repositories that contain multiple related single-file
packages, package-vc-install creates looped self-dependency that can cause errors.

For example, trying to install the repository:
https://github.com/armindarvish/consult-omni
will result in "Lisp nesting exceeds ‘max-lisp-eval-depth’: 1601" error. This is
because currently package-vc-install tries to read all ".el" files in the root
directory to get the dependencies and build the "define-package" declaration in
consult-omni-pkg.el. This is not compatible with repositories that have multiple
single-file packages in the root directory. Instead, the dependencies should be
inferred from the main lisp file only. This will be safe with multi-file packages
as well because the convention is to have the "Package-Requires:" header only in
the main lisp file and not the additional lisp files.

What version of Emacs are you using? Installing your repository doesn't
raise any error when I try to do so.

There are other packages that have multiple single-file packages as well, for
example, https://github.com/oantolin/embark includes embark and embark-consult in
the root directory. Currently, installing embark with package-vc-install causes
several different versions of embark being downlaoded because the dependencies are
read from all of those files even though they are meant to be separate packages.

The issue we have to keep in mind is that since we add the repository
directly to `load-path', all the files can be used no matter what
"specific" file you might intend to use. To retain usability and not
have unexpected function calls fail, we rather install all the
dependencies. The recursion error above hints at some programming
issue, where we don't terminate properly.

>

Best Regards,
Armin Darvish

–

---

[www.armindarvish.com]

[www.armindarvish.com] https://www.armindarvish.com/

–

Best Regards,