Building Emacs 25.2 on XUbuntu 17.04

I haven’t done much with Ubuntu recently, but had to set up a laptop with XUbuntu 17.04. That came with Emacs 24.5 as the default emacs package, and as skeeto pointed out in the comments, with a separate emacs25 package for Emacs 25.1. I tend to run the latest release Emacs everywhere out of habit, so I revisited my build instructions to build a current Emacs on Ubuntu and its derivates. The good news is that in thanks to some changes in the Emacs build, the build is as straightforward as it used to be prior to the combination of Ubuntu 16.10 and Emacs 25.1. In other words, no need to remember to switch off PIE as was necessary when building GNU Emacs 25.1 on Ubuntu 16.10.

Here’s a brief recap of the build steps so you don’t have to go back and click your way through my old posts.

First, if you haven’t enabled the ‘source code’ repository in Ubuntu’s software sources, do so now. If you don’t, you’ll run into the following error when installing the build dependencies for Emacs:

E: You must put some 'source' URIs in your sources.list

Assuming you have added the source code repositories to your software sources, execute the following commands. The first command installs the build tools, the second one installs all the build dependencies for the stock Emacs build. Those dependencies will give you a fully functioning GUI Emacs. If you need additional third party libraries for additional functionality that aren’t covered by the regular Ubuntu Emacs build dependencies, make sure you install those also. I usually go with the stock configuration so for me, these are the two commands I need to run:

sudo apt install build-essential
sudo apt build-dep emacs25

On my fresh install of XUbuntu 17.04, the build-essential packages were already installed, so it may not be necessary to execute that step any longer. However, it was necessary in the past so I’m still leaving it in there as it makes sure you have the normal build setup.

You can install the build-deps for either the emacs or the emacs24 package instead of the one for the emacs25 package as I show in the example above. They all appear to install the same dependencies as trying to install all three doesn’t appear to result in any additional packages being installed.

At this point, it’s time to download the GNU Emacs 25.2 tarball from your favourite GNU mirror, extract it to a suitable place and do the usual configure/make/make install dance. I prefer to install my home built binaries in a local subtree in my user directory, hence the $HOME/local prefix passed to configure:

./configure --prefix=$HOME/local
make && make install

At this point, we’re good to go:

timo-xubuntu-VirtualBox% emacs --version
GNU Emacs 25.2.1
Copyright (C) 2017 Free Software Foundation, Inc.
GNU Emacs comes with ABSOLUTELY NO WARRANTY.
You may redistribute copies of GNU Emacs
under the terms of the GNU General Public License.
For more information about these matters, see the file named COPYING.

The instructions above will also work for building Emacs 25.2 on older versions of Ubuntu, although you have to make sure that you pick the correct build-dep package to install the build dependencies first.

RTFM, or how to make unnecessary work for yourself editing inf-mongo

Turns out I made some unnecessary “work” for myself when I tried to add support for command history to inf-mongo. As Mickey over at Mastering Emacs points out in a blog post, comint mode already comes with M-n and M-p mapped to comint-next-input and comint-previous-input. And of course they work in inf-mongo right out of the box. I still prefer using M-up and M-down, plus I learned a bit about sparse key maps and general interaction with comint-mode. So from that perspective, no time was wasted although it wasn’t strictly necessary to put in the work.

But with Emacs being the box of wonders it is, it’s still fun to learn about features and new ways of doing things even after using it for a couple of decades.

There are a more gems hidden in Mickey’s blog post so if you’re using anything that is based on comint, I would really recommend reading it.

Extending inf-mongo to support scrolling through command history

I’m spending a lot of time in the MongoDB shell at the moment, so of course I went to see if someone had built an Emacs mode to support the MongoDB shell. Google very quickly pointed me at endofunky’s inf-mongo mode, which implements a basic shell interaction mode with MongoDB using comint. We have a winner, well, almost. The mode does exactly what it says on the tin, but I wanted a little more, namely being able to scroll through my command history. Other repl modes like Cider have this functionality already, so it couldn’t be too hard to implement, could it?

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What happened to XEmacs?

I used XEmacs quite a lot in the 2000s before I switched back to the more stable GNU Emacs. That was back then before GNU Emacs offered a stable official Windows build when XEmacs did, and at the time I was doing a lot of Windows development.

Out of curiosity and for some research I tried to look into the current state of the project and found that the www.xemacs.org appears to be unreachable. The domain still exists and according to whois was last updated in September 2015. The XEmacs Sourceforge page is still around, but appears to have received its last set of updates in 2009. Obviously a lot of links to the bug tracker, mailing list hosts etc are dead as they’re point to subdomains of xemacs.org.

Anybody know what happened to the project? The only reference I found was a post from January 2016 on a website I’ve never heard of (8ch.net) referencing a post on the XEmacs development that I can’t get at anymore (becauses lists.xemacs.org is dead) that suggests XEmacs development is officially dead now.

Building Emacs 25.1 on Ubuntu 16.10

A reader of this blog kindly pointed out that my instructions for building Emacs 25.1 on Ubuntu 16.10 result in a core dump when the build process bootstraps emacs. I only tested the instructions on 16.04 so I hadn’t run into this issue yet.

The core dump on 16.10 appears to be a known issue and there is a workaround. Instead of running configure with just the prefix argument, run it as follows:

./configure CFLAGS=-no-pie --prefix=$HOME/local

The in-depth bug description is here in message #38. The short version is that gcc in Ubuntu 16.10 defaults to building code with -pie and this breaks Emacs. Turning off -pie results in a working executable.

How to build GNU Emacs 25.1 on (X)Ubuntu 16.04

Now that GNU Emacs 25.1 has been released, it is time for my customary “how to install Emacs 25.1 on a recent Ubuntu” post. In my case I’m using XUbuntu 16.04, but the instructions are pretty much the same for just about every recent Ubuntu version. The package versions of the referenced packages differ, but the package names haven’t changed since I first published one of these posts.

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