Emacs 21 complains that vm-disable-extents is undefined

[Göran Uddeborg]

Trying out VM 8.1.93a on a RHEL5 system with emacs 21.4, I get an error message on startup:

    vm-do-summary: Symbol's function definition is void: vm-disable-extents

With a quick "grep" I figured out this is fset to remove-overlays in vm-misc.el. But remove-overlays does not seem to be defined in emacs 21. At least describe-function can't find it. According to vm-check-emacs-version in 8.1.93a, emacs 21 should still be supported.

[Uday Reddy (reddyuday)]

This will be fixed in the next release. However, I would recommend that you switch to Emacs 22.x as soon as possible. Things are changing a bit too fast in the Emacs world and we are having to keep up.

[Göran Uddeborg (goeran-uddeborg)]

I certainly will upgrade as soon as possible! When I can choose, I use emacs 23. :-)

But in the environment I discovered this, I'm restricted to what comes with Red Hat Enterprise Linux 5, and that is emacs 21. Eventually, it will be migrated to RHEL 6 which was released a few months ago, but enterprise environments rarely move quickly.

[Tim Cross (tcross)]

2011/1/27 Göran Uddeborg <email address hidden>

> I certainly will upgrade as soon as possible! When I can choose, I use
> emacs 23. :-)
>
> But in the environment I discovered this, I'm restricted to what comes
> with Red Hat Enterprise Linux 5, and that is emacs 21. Eventually, it
> will be migrated to RHEL 6 which was released a few months ago, but
> enterprise environments rarely move quickly.
>
> --
>
> Wow! I didn't know RHEL5 was that out of date re: emacs. Emacs 22 was
released in June 2007 and Emacs 23 in July 2009. While we use RHEL on many
of our servers, we gave up on the RHEL desktop version as it just got out of
date too quickly. Stability is important in servers, but I think less so for
desktops.

We now allow staff to run whatever Linux desktop version they like, provided
it is a stable release. I make extensive use of tramp and fuse, so there is
no need to run emacs remotely when doing work on any of the servers.

I have recently given up on packaged versions of emacs as so many
distributions seem to be out of date and I kept running into issues that
were already solved in current releases. Even emacs 22 has significant
improvements over 21.

Note that it is quite straight-forward to build and run emacs as a normal
user i.e. no need to run 'make install' as root. So, if the reason you
cannot update to a more recent version is because you don't have permission
to install packages or run as root, you can just do it in your home
directory. You may not be able to have all the new features if you cannot
install necessary libraries, but at least you would be running a current
version.

Tim

[Uday Reddy (reddyuday)]

Irrespective of the merits and demerits of these things, we can't dictate to enterprises. They make their own decisions for their own reasons.

My principle is to support old versions as long as it is feasible to do so. I have updated the README file to say that, while we allow Emacs 21, Emacs 22 is recommended.

Early input from Goeran on what things break on Emacs 21 would be quite useful.

[Göran Uddeborg (goeran-uddeborg)]

> I didn't know RHEL5 was that out of date

Isn't being out of date what enterprise editions are all about? :-)

Going into details would go too far off topic. Let me just say that it is impractical for me to maintain a private build of emacs on all the different platforms I maintain.

But VM is small (and I only use it on one of platform), so I can do some testing there. I'll clone the tip of the 8.2.x branch and see if I can use it or if I find more emacs 21-incompatibilities.

[Uday Reddy (reddyuday)]

Göran Uddeborg writes:

> But VM is small (and I only use it on one of platform), so I can do some
> testing there. I'll clone the tip of the 8.2.x branch and see if I can
> use it or if I find more emacs 21-incompatibilities.

Hi Goeran, please use the trunk branch instead of 8.2.x. The latter
will get maintained only after the release of 8.2.0b.

Cheers,
Uday

[Göran Uddeborg (goeran-uddeborg)]

> please use the trunk branch instead

I'll do so, and file separate issues about what I find. The first one is bug 709070.