Thursday, December 27, 2012

My personal KDEPIM upgrade (again): laptop

One year after my last blog post on this topic I encountered some minor difficulties with combining KDEPIM-4.4 (i.e. kmail1) and the KDE 4.10 betas. These difficulties are fixed now, and the combination seems to work fine again. Anyway, I became curious about the level of stability of Akonadi-based kmail2 once more. After all, I've been running it continuously over the year on my office desktop with a constant-on fast internet connection, and that works quite well. So, I gave it a fresh try on my laptop too. I deleted my Akonadi configuration and cache, switched to Akonadi mysql backend, updated kmail and the rest of KDEPIM without migrating to 4.9.4, and re-added my IMAP account from scratch (with "Enable offline mode"). The overall use case description is "laptop with large amount of cached files from IMAP account, fluctuating internet connectivity". Now, here are my impressions...
  • Reaction time is occasionally sluggish, but overall OK.
  • The progress indicator behaves a bit odd, it checks the mail folders in seemingly random order and only knows 0% and 100% completion.
  • Random warning messages. It seems that kmail2 uses some features that "my" IMAP server does not understand. So, I'm getting frequent warning notifications that don't tell me anything and that I cannot do anything about. SET ANNOTATION, UID, ... Please either handle the errors, inform the user what exactly goes wrong, or ignore them in case they are irrelevant. Filed as a wish, bug 311265.
  • Network activity stops working sometime. This sounds worse than it actually is, since in 99% of all cases Akonadi now detects fine that the connection to the server is broken (e.g., after suspend/resume, after switching to a different WLAN, or after enabling a VPN tunnel) and reconnects immediately. In the few remaining cases, re-starting the Akonadi server does the trick. You just have to know what to kick.
  • More problematic is, while you're in online mode, any problems with connectivity will make kmail "hang". Clicking on a message leads to an attempt to retrieve it, which requires some response from the network. As it seems to me, all such requests are queued up for Akonadi to handle, and if that does not get a reply, pending requests are stuck in the queue... OK, you might say that this is a typical use case for offline mode, but then I would have to be able to predict when exactly my train enters the tunnel... Compare this to kmail1 disconnected IMAP accounts, where regular syncing would be delayed, but local work remained unaffected.
  • Offline mode is a nice concept, and half a solution for the last problem, but unfortunately it does not work as expected. For mysterious reasons, a considerable part of the messages is not cached locally. I switch my account to offline mode, click on a message, and obtain an error message "Cannot fetch this in offline mode". Well, bummer. Bug 285935.
  • This may just be my personal taste, but once something goes wrong (e.g., non-kde related crash, battery empty, ...) and the cache becomes corrupted somehow, I'd like to be able to do something from kmail2 without having to fiddle with akonadiconsole. A nice addition would be "Invalidate cache" in the context menu of a mail folder, or some sort of maintenance menu with semi-safe options.
  • Finally... something is definitely going wrong with PGP signatures; the signatures do not always verify on other mail clients. Tracking this down, it seems that CRLF is not preserved in messages, see bug 306005.
On the whole, for the laptop use case the "new" KDEPIM is now (4.9.4) more mature than the last time I tried. I'll keep it now and not downgrade again, but there are still some significant rough edges. The good thing is, the KDEPIM developers are aware of the above issues and debugging is going on, as you can see for example from this blog post by Alex Fiestas (whose use case pretty much mirrors my own).

Sunday, December 16, 2012

The difference between Ubuntu and Gentoo ;)

This gem comes from the xda developers forums; thanks barry99705!

"Using/installing Ubuntu is like buying a car. It may have a few features you'll never need or use, and might need to have a couple features added as aftermarket parts.

Using/installing Gentoo is like buying a pile of sheet metal, a few rubber trees, small pile of copper, a pile of sand, and an oil well. Then you have to cut and fabricate the car's body from the sheet metal, extract the rubber from the trees, then use that to make the tires and all the seals on the car. Use the pile of copper to make all the wires, and use the leftover rubber(you did save the scraps didn't you) to make the insulation. Melt down the pile of glass to make the windshield, side and back windows, also the headlights and lights themselves. Then you need to extract the crude oil from the well to refine your own engine oil and gas. In the end, you have a car created to your exact specifications (if you know what the hell you're doing) that may or may not be any better than just buying a car off the lot."

Of course I should additionally mention that Gentoo provides awesome documentation for all the steps and most of the actual assembly work is done single-handedly by portage!

Thursday, December 13, 2012

How app-office/libreoffice-bin is made

While usually Gentoo users compile all their packages on their own computers, LibreOffice tends to be too big a bite for that. This is why we provide for amd64 and x86 app-office/libreoffice-bin and app-office/libreoffice-bin-debug, two packages with a precompiled binary installation and its debug information. In the beginning we just used the binaries from the official LibreOffice distribution. Turns out, however, that these binaries bundle a large number of libraries that we have in Gentoo anyway (bug 361695), and for a lot of reasons bundled libraries are bad. So, we decided to roll our own binaries for stable Gentoo installations. Let me describe a bit how it is done.
Linux pinacolada 3.4.9-gentoo #2 SMP Thu Oct 11 00:05:55 CEST 2012 x86_64 Intel(R) Core(TM) i7 CPU 920 @ 2.67GHz GenuineIntel GNU/Linux
On the machine doing the build, two chroots are dedicated to the package build process, one a plain amd64 chroot, the other an x86 chroot entered via linux32. Both have no ~arch packages installed at all, only stable keywords are accepted; both have a very minimal world file listing only a few packages useful for a maintainer as e.g. gentoolkit or eix. Procedure is identical for both.  In addition, in both chroots the compiler flags are chosen for as wide compatibility as possible. This means
# for x86
CFLAGS="-march=i586 -mtune=generic -O2 -pipe -g"
# for amd64
CFLAGS="-march=x86-64 -mtune=generic -O2 -pipe -g"
and obviously the same for CXXFLAGS. Both chroots also use the portage features splitdebug and compressdebug to make debug information available in a separate directory tree. Prior to build, the existing packages are updated, unnecessary packages are cleaned, and dynamic linking is checked:
emerge --sync
emerge -uDNav world
emerge --depclean --ask

In case any problems occur, these are checked, solved, and the procedure is repeated until all the operations become a no-op.
Next step is adapting the (rather simplistic) build script to the new libreoffice version. This means mainly checking for new or discarded useflags, and deciding which value these should have in the binary build. Since LibreOffice-3.6 we also have to decide now which bundled extensions to build. The choice of useflags is influenced by several factors. For example, pdfimport is disabled because the resulting dependency on poppler might lead to broken binaries rather too often.
Then, well, then it's running the build. Generating all 12 flavours (base, kde, gnome with and without java for both amd64 and x86) takes roughly a weekend. Time to go out to the christmas market and sip a Gl├╝hwein.
In the meantime, we can also adapt the libreoffice-bin ebuilds for the new version. The defined phase functions are mostly boring, since they only have to copy files into the system. Normally, they can be taken over from the previous version. The dependency declarations, however, have to be copied anew each time from the corresponding app-office/libreoffice ebuild, taking into account the chosen use-flag values. DEPEND is set empty since we're not actually building anything during installation.
Finally, COMMON_DEPEND is extended by an additional block named BIN_COMMON_DEPEND, specific for the binary package. Here, we specify any dependencies that need to be stricter now, where a library upgrade would for a normal package require revdep-rebuild - which is not possible for a binary package. Typical candidates where we have to fix the minimum or exact library version are glibc, icu, or libcmis.
Once the build has finished, 8.8G of files have to be uploaded to the Gentoo server, added to the mirror system, and then given some time to propagate. Then, we can commit the new ebuild, and open a stabilization request bug. Finished!
(Oh and in case you're wondering, new packages are coming tomorrow. :)