bug#63757: 29.0.91 order of package paths changed: random old versions of packages in load-path

[Евгений Бойков]

> Done.  Should we close the issue then, or wait for more feedback?

fa8135f8916 * emacs-29 origin/emacs-29 Revert changes to the order in which package descs are loaded
-      (dolist (pkg-dir (directory-files dir t "\\`[^.]" t))
+      (dolist (pkg-dir (directory-files dir t "\\`[^.]"))

it doesn't fix the initial problem: `load-path` and `package-alist` are still broken in my test.

Test:
To reproduce the case we need emacs 29.0.91 + fa8135f8916 fix  and
    ~/.emacs.d/elpa/go-mode-20170726.555/...
    ~/.emacs.d/elpa/go-mode-20220114.2239/...
Run `emacs -Q` and `M-x package-initialize`. After that `package-alist` and `load-path` contain the 2017 version as the first item in the list (instead of 2022).

It can be fixed like this:

diff --git a/lisp/emacs-lisp/package.el b/lisp/emacs-lisp/package.el
index ba0e3618f28..6eaf261f5f4 100644
--- a/lisp/emacs-lisp/package.el
+++ b/lisp/emacs-lisp/package.el
@@ -922,11 +922,13 @@ correspond to previously loaded files."
                                  (v2 (package-desc-version p2)))
                              (or
                               ;; Prefer VC packages.
-                              (package-vc-p p1)
-                              (package-vc-p p2)
+                              (and
+                               (package-vc-p p1)
+                               (not (package-vc-p p2)))
                               ;; Prefer builtin packages.
-                              (package-disabled-p p1 v1)
-                              (not (package-disabled-p p2 v2))))))))
+                              (and
+                               (package-built-in-p p1 v1)
+                               (not (package-built-in-p p2 v2)))))))))
     ;; Check if PACKAGE is available in `package-alist'.
     (while
         (when pkg-descs

But if we leave it until 29.2, I will not insist :)

On Sun, Jun 4, 2023 at 11:21 PM Philip Kaludercic <philipk@posteo.net> wrote:

Eli Zaretskii <eliz@gnu.org> writes:

>> From: Philip Kaludercic <philipk@posteo.net>
>> Cc: artscan@list.ru,  monnier@iro.umontreal.ca,  63757@debbugs.gnu.org
>> Date: Sun, 04 Jun 2023 12:32:17 +0000
>>
>> Eli Zaretskii <eliz@gnu.org> writes:
>>
>> >> -      (dolist (pkg-dir (directory-files dir t "\\`[^.]" t))
>> >> +      (dolist (pkg-dir (directory-files dir t "\\`[^.]"))
>> >>          (when (file-directory-p pkg-dir)
>> >>            (package-load-descriptor pkg-dir))))))
>> >> 
>> >> (I attached the *vc-diff* buffer, but before sending the message I
>> >> invoked vc-diff again which modified the buffer contents.  Should have
>> >> just copied the diff manually...)
>> >
>> > Thanks, now it at least makes sense.
>> >
>> > But why does it matter whether the package directory names are sorted
>> > or not?  Is sorting package versions the same as sorting the names of
>> > their directories?
>>
>> No, because directories are sorted by their names and by that metric,
>> "foo-10" is less than "foo-9".  But since package archives like MELPA
>> use ISO 8601-like release-dates as version numbers, the order "works".
>> If we disable sorting, the files returned in any order the operating
>> system might have arbitrary stored the directory entries in which might
>> even change depending on the file system.  So at the very least we can
>> argue that while sorting does not solve the issue, it provides a quick
>> hack to prevent sudden breakage from Emacs 28 to Emacs 29, due to users
>> relying on this kind of behaviour.  A proper solution, that takes
>> version numbers into account should be prepared on the master branch.
>
> OK, thanks.  Please install on emacs-29, and let's hope this doesn't
> cause new problems.

Done.  Should we close the issue then, or wait for more feedback?

--

__________________________

С уважением,
Бойков Евгений Алексеевич
сот. 8-924-202-25-65
e-mail: artscan@list.ru