Allowing rolling release packages on ELPA

[Philip Kaludercic]

I have heard from people who prefer a rolling release model for their
packages, and requested that their packages not be added for {Non,}GNU
ELPA if they would have to update the version header manually,
presumably on every commit.  The following patch would enable ELPA
devel-like versioning on ELPA, if enabled with a :rolling-release
property.  WDYT?

>From e6c928873683c9f5147ee6cb1301047b47b3208f Mon Sep 17 00:00:00 2001
From: Philip Kaludercic <philipk@posteo.net>
Date: Sun, 16 Oct 2022 18:05:40 +0200
Subject: [PATCH] Add support for rolling-release packages

* README: Document :rolling-release
* elpa-admin.el (elpaa--get-release-revision): Respect
:rolling-release.
(elpaa--make-one-package): Respect :rolling-release.
---
 README        | 6 +++++-
 elpa-admin.el | 3 +++
 2 files changed, 8 insertions(+), 1 deletion(-)

diff --git a/README b/README
index 4ff305047a..2e8a9e1156 100644
--- a/README
+++ b/README
@@ -1,5 +1,5 @@
 #+TITLE: ELPA-Admin README
-#+DATE: 2022-01-06
+#+DATE: 2022-10-16
 
 Copyright (C) 2010-2022 Free Software Foundation, Inc. \\
 See the end of the file for license conditions.
@@ -168,6 +168,10 @@ this ORIG-VERSION (or REMAPPED-VERSION if non-nil) to 
override
 the default heuristic which uses the last revision that modified the
 "Version:" header.
 
+** =:rolling-release FLAG=
+If FLAG is non-nil, a new package will be released for every new
+commit, instead of just when the "Version" header is incremented.
+
 * Configuration (elpa-config)
 
 The configuration file is a `lisp-data-mode` file containing
diff --git a/elpa-admin.el b/elpa-admin.el
index d8f84e7205..054c9bda86 100644
--- a/elpa-admin.el
+++ b/elpa-admin.el
@@ -194,6 +194,7 @@ commit which modified the \"Version:\" pseudo header."
               (not (member vers (car version-map))))
     (pop version-map))
   (or (nth 2 (car version-map))
+      (and (elpaa--spec-get pkg-spec :rolling-release) "HEAD")
       ;; When the mainfile is a symlink (e.g. for :core packages), run Git
       ;; in the directory that holds the actual file, otherwise Git won't
       ;; know what file we're talking about.
@@ -952,6 +953,8 @@ place the resulting tarball into the file named 
TARBALL-ONLY."
                        (lambda () (cdr last-rel)))
                   (elpaa--release-email pkg-spec metadata dir)))))))
          (t
+          (when (elpaa--spec-get pkg-spec :rolling-release)
+            (setq vers devel-vers))
           (let ((tarball (concat elpaa--release-subdir
                                  (format "%s-%s.tar" pkgname vers))))
             (when (elpaa--make-one-tarball
-- 
2.38.0

I guess a counter argument is that you can use `time-stamp' with a
adequate file local configuration, I can't really say which is better.