Shallow Thoughts : tags : irc

Debian: Holding packages you build from source, and rebuilding them easily

Recently I wrote about building the Debian hexchat package to correct a key binding bug.

I built my own version of the hexchat packages, then installed the ones I needed:

dpkg -i hexchat_2.10.2-1_i386.deb hexchat-common_2.10.2-1_all.deb hexchat-python_2.10.2-1_i386.deb hexchat-perl_2.10.2-1_i386.deb

That's fine, but of course, a few days later Debian had an update to the hexchat package that wiped out my changes.

The solution to that is to hold the packages so they won't be overwritten on the next apt-get upgrade:

aptitude hold hexchat hexchat-common hexchat-perl hexchat-python

If you forget which packages you've held, you can find out with aptitude:

aptitude search '~ahold'

Simplifying the rebuilding process

But now I wanted an easier way to build the package. I didn't want to have to search for my old blog post and paste the lines one by one every time there was an update -- then I'd get lazy and never update the package, and I'd never get security fixes.

I solved that with a zsh function:

newhexchat() {
    # Can't set errreturn yet, because that will cause mv and rm
    # (even with -f) to exit if there's nothing to remove.
    cd ~/outsrc/hexchat
    echo "Removing what was in old previously"
    rm -rf old
    echo "Moving everything here to old/"
    mkdir old
    mv *.* old/

    # Make sure this exits on errors from here on!
    setopt localoptions errreturn

    echo "Getting source ..."
    apt-get source hexchat
    cd hexchat-2*
    echo "Patching ..."
    patch -p0 < ~/outsrc/hexchat-2.10.2.patch
    echo "Building ..."
    debuild -b -uc -us
    echo
    echo 'Installing' ../hexchat{,-python,-perl}_2*.deb
    sudo dpkg -i ../hexchat{,-python,-perl}_2*.deb
}

Now I can type newhexchat and pull a new version of the source, build it, and install the new packages.

How do you know if you need to rebuild?

One more thing. How can I find out when there's a new version of hexchat, so I know I need to build new source in case there's a security fix?

One way is the Debian Package Tracking System. You can subscribe to a package and get emails when a new version is released. There's supposed to be a package tracker web interface, e.g. package tracker: hexchat with a form you can fill out to subscribe to updates -- but for some packages, including hexchat, there's no form. Clicking on the link for the new package tracker goes to a similar page that also doesn't have a form.

So I guess the only option is to subscribe by email. Send mail to pts@qa.debian.org containing this line:

subscribe hexchat [your-email-address]

This may turn out to generate too much mail: I've only just subscribed, so I don't know yet. There are supposedly keywords you can use to limit the subscription, such as upload-binary and upload-source, but the instructions aren't at all clear on how to include them in your subscription mail -- you say keyword, or keyword your-email, so where do you put the actual keywords you want to accept? They offer no examples.

Use apt to check whether your version is current

If you can't get the email interface to work or suspect it'll be too much email, you can use apt to check whether the current version in the repository is higher than the one you're running:

apt-cache policy hexchat

You might want to automate that, to make it easy to check on every package you've held to see if there's a new version. Here's a little shell function to do that:

# Check on status of all held packages:
check_holds() {
    for pkg in $( aptitude search '~ahold' | awk '{print $2}' ); do
        policy=$(apt-cache policy $pkg)
        installed=$(echo $policy | grep Installed: | awk '{print $2}' )
        candidate=$(echo $policy | grep Candidate: | awk '{print $2}' )
        if [[ "$installed" == "$candidate" ]]; then
            echo $pkg : nothing new
        else
            echo $pkg : new version $candidate available
        fi
    done
}

Migrating from xchat: a couple of hexchat fixes

I decided recently to clean up my Debian "Sid" system, using apt-get autoclean, apt-get purge `deborphan`, aptitude purge ~c, and aptitude purge ~o. It gained me almost two gigabytes of space. On the other hand, it deleted several packages I had long depended on. One of them was xchat.

I installed hexchat, the fully open replacement for xchat. Mostly, it's the same program ... but a few things didn't work right.

Script fixes

The two xchat scripts I use weren't loading. Turns out hexchat wants to find its scripts in .config/hexchat/addons, so I moved them there. But xchat-inputcount.pl still didn't work; it was looking for a widget called "xchat-inputbox". That was fairly easy to patch: I added a line to print the name of each widget it saw, determined the name had changed in the obvious way, and changed

    if( $child->get( "name" ) eq 'xchat-inputbox' ) {

    if( $child->get( "name" ) eq 'xchat-inputbox' ||
        $child->get( "name" ) eq 'hexchat-inputbox' ) {

Notifying me if someone calls me

The next problem: when someone mentioned my nick in a channel, the channel tab highlighted; but when I switched to the channel, there was no highlight on the actual line of conversation so I could find out who was talking to me. (It was turning the nick of the person addressing me to a specific color, but since every nick is a different color anyway, that doesn't make the line stand out when you're scanning for it.)

The highlighting for message lines is set in a dialog you can configure: Settings→Text events...
Scroll down to Channel Msg Hilight and click on that elaborate code on the right: %C2<%C8%B$1%B%C2>%O$t$2%O
That's the code that controls how the line will be displayed.

Some of these codes are described in Hexchat: Appearance/Theming, and most of the rest are described in the dialog itself. $t is an exception: I'm not sure what it means (maybe I just missed it in the list).

I wanted hexchat to show the nick of whoever called me name in inverse video. (Xchat always made it bold, but sometimes that's subtle; inverse video would be a lot easier to find when scrolling through a busy channel.) %R is reverse video, %B is bold, and %O removes any decorations and sets the text back to normal text, so I set the code to: %R%B<$1>%O $t$2 That seemed to work, though after I exited hexchat and started it up the next morning it had magically changed to %R%B<$1>%O$t$2%O.

Hacking hexchat source to remove hardwired keybindings

But the big problem was the hardwired keybindings. In particular, Ctrl-F -- the longstanding key sequence that moves forward one character -- in hexchat, it brings up a search window. (Xchat had this problem for a little while, many years ago, but they fixed it, or at least made it sensitive to whether the GTK key theme is "Emacs".)

Ctrl-F doesn't appear in the list under Settings→Keyboard shortcuts, so I couldn't fix it that way. I guess they should rename that dialog to Some keyboard shortcuts. Turns out Ctrl-F is compiled in. So the only solution is to rebuild from source.

I decided to use the Debian package source:

apt-get source hexchat

The search for the Ctrl-F binding turned out to be harder than it had been back in the xchat days. I was confident the binding would be in one of the files in src/fe-gtk, but grepping for key, find and search all gave way too many hits. Combining them was the key:

egrep -i 'find|search' *.c | grep -i key

That gave a bunch of spurious hits in fkeys.c -- I had already examined that file and determined that it had to do with the Settings→Keyboard shortcuts dialog, not the compiled-in key bindings. But it also gave some lines from menu.c including the one I needed:

    {N_("Search Text..."), menu_search, GTK_STOCK_FIND, M_MENUSTOCK, 0, 0, 1, GDK_KEY_f},

Inspection of nearby lines showed that the last GDK_KEY_ argument is optional -- there were quite a few lines that didn't have a key binding specified. So all I needed to do was remove that GDK_KEY_f. Here's my patch:

--- src/fe-gtk/menu.c.orig      2016-02-23 12:13:55.910549105 -0700
+++ src/fe-gtk/menu.c   2016-02-23 12:07:21.670540110 -0700
@@ -1829,7 +1829,7 @@
        {N_("Save Text..."), menu_savebuffer, GTK_STOCK_SAVE, M_MENUSTOCK, 0, 0,
 1},
 #define SEARCH_OFFSET (70)
        {N_("Search"), 0, GTK_STOCK_JUSTIFY_LEFT, M_MENUSUB, 0, 0, 1},
-               {N_("Search Text..."), menu_search, GTK_STOCK_FIND, M_MENUSTOCK,
 0, 0, 1, GDK_KEY_f},
+               {N_("Search Text..."), menu_search, GTK_STOCK_FIND, M_MENUSTOCK,
 0, 0, 1},
                {N_("Search Next"   ), menu_search_next, GTK_STOCK_FIND, M_MENUS
TOCK, 0, 0, 1, GDK_KEY_g},
                {N_("Search Previous"   ), menu_search_prev, GTK_STOCK_FIND, M_M
ENUSTOCK, 0, 0, 1, GDK_KEY_G},
                {0, 0, 0, M_END, 0, 0, 0},

After making that change, I rebuilt the hexchat package and installed it:

sudo apt-get build-dep hexchat
sudo apt-get install devscripts
cd hexchat-2.10.2/
debuild -b -uc -us
sudo dpkg -i ../hexchat_2.10.2-1_i386.deb

Update: I later wrote about how to automate this here: Debian: Holding packages you build from source, and rebuilding them easily.

And the hardwired Ctrl-F key binding was gone, and the normal forward-character binding from my GTK key theme took over.

I still have a couple of minor things I'd like to fix, like the too-large font hexchat uses for its channel tabs, but those are minor. At least I'm back to where I was before foolishly deciding to clean up my system.

Writing xchat scripts in Python (to play sound alerts)

I use xchat as my IRC client. Mostly I like it, but its sound alerts aren't quite as configurable as I'd like. I have a few channels, like my Bitlbee Twitter feed, where I want a much more subtle alert, or no alert at all. And I want an easy way of turning sounds on and off, in case I get busy with something and need to minimize distractions.

Years ago I grabbed a perl xchat plug-in called "Smet's NickSound" that did something close to what I wanted. I've hacked a few things into it. But every time I try to customize it any further, I'm hit with the pain of write-only Perl. I've written Perl scripts, honest. But I always have a really hard time reading anyone else's Perl code and figuring out what it's doing. When I dove in again recently to try to figure out why I was getting so many alerts when first starting up xchat, I finally decided: learning how to write a Python xchat script couldn't be any harder than reverse engineering a Perl one.

First, of course, I looked for an existing nick sound Python script ... and totally struck out. In fact, mostly I struck out on finding any xchat Python scripts at all. I know there are Python bindings for xchat, because there's documentation for them. But sample plug-ins? Nope. For some reason, nobody's writing xchat plug-ins in Python.

I eventually found two minimal examples: this very simple example and the more elaborate utf8decoder. I was able to put them together and cobble up a working nick sound plug-in. It's easy once you have an example to work from to help you figure out the event hook arguments.

So here's my own little example, which may help the next person trying to learn xchat Python scripting: chatsounds.py on github.

Starting a line with a slash in xchat

/join #channel

/me waves to everyone

Great, but what if I want to start a line with a slash?

On some IRC clients, you can type two slashes, e.g.

/ /me tries

On xchat, what you need is /say:

/say /me succeeds!

Silly little tip, but I know I'll forget it if I don't record it ... and I bet I'm not the only xchat user wondering how to do this.

//me tries