Thanks for the quick response! It would be great indeed if `package-get-version` worked in more cases and we could just consider it the canonical solution the version extraction problem.
> Basically I want to extract the package version from the *Version:*
> header instead of having to duplicate it. I know of
> package-get-package-version, but I assume it won't work for people
> who didn't install my packages via package.el.
`package-get-version` should work but only if they had the foresight to
put it in a directory whose name ends in "-<version>" or whose name is
just `cider` (i.e. the name of your package) :-(
The patch below (which I plan to push to `master` soon) should make it
work in other cases as well if the call is in the same file where the
`Version:` can be found.
Stefan
diff --git a/lisp/emacs-lisp/package.el b/lisp/emacs-lisp/package.el
index 9b6b5d4dc0d..d477266a7ef 100644
--- a/lisp/emacs-lisp/package.el
+++ b/lisp/emacs-lisp/package.el
@@ -4077,7 +4077,9 @@ package-get-version
"Return the version number of the package in which this is used.
Assumes it is used from an Elisp file placed inside the top-level directory
of an installed ELPA package.
-The return value is a string (or nil in case we can't find it)."
+The return value is a string (or nil in case we can't find it).
+It works in more cases if the call is in the file which contains
+the `Version:' header."
;; In a sense, this is a lie, but it does just what we want: precompute
;; the version at compile time and hardcodes it into the .elc file!
(declare (pure t))
@@ -4096,6 +4098,7 @@ package-get-version
(let* ((pkgdir (file-name-directory file))
(pkgname (file-name-nondirectory (directory-file-name pkgdir)))
(mainfile (expand-file-name (concat pkgname ".el") pkgdir)))
+ (unless (file-readable-p mainfile) (setq mainfile file))
(when (file-readable-p mainfile)
(require 'lisp-mnt)
(with-temp-buffer