| Colin Watson | |||||
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Thu, 02 Jul 2009
Joey Hess posted a draft of a code_swarm video for d-i a couple of weeks ago, which reminded me that I've been meaning to do something similar for Ubuntu for a while now as it's just about our archive's fifth birthday. I have a more or less complete archive of all our -changes mailing lists locally (I think I'm missing some of the very early ones, before the end of July 2004; let me know if you were one of the very early Canonical employees and have a record of these), and with the aid of launchpadlib it's fairly easy to map all the e-mail addresses into Launchpad user names, massage out some of the more obvious duplicates, and then treat the stream of uploads as if it were a stream of commits. If you haven't seen code_swarm before, each dot represents an upload, and the dots "swarm" around their corresponding committers' names; more active committers have larger swarms of dots and brighter names. I assigned a colour to each of our archive components (uploads aren't really at the C code vs. Python code vs. translations vs. whatever kind of granularity that you see in other code_swarm videos), which mostly means that people who predominantly upload to main are in roughly an Ubuntu tan colour, people who predominantly upload to universe are coloured bluish, and people with a good mixture tend to come out coloured green. If I get a bit more time I may try to figure out enough about video editing software to add some captions. Here's the video (194 MB). A while back, the BBC approached Canonical about providing seamless access to unencumbered BBC content for all Ubuntu users (in the UK and elsewhere). We agreed to approach this by way of a plugin for our primary media player, Totem, and asked Collabora Multimedia to do the plugin development work. The results are in what will shortly be released as Ubuntu 8.10, and are looking really rather good. At the moment the content available from the BBC at present is mostly audio, but support for video is in place and the feed is expected to be fleshed out here over time. We have a genre classification scheme in place, and will see how that scales as the amount of available content grows. The code has been submitted upstream, although there are still a few issues to work out there. This is not the same thing as iPlayer; all the content available here is DRM-free. Some of it is geographically restricted to the UK, and these restrictions are handled on the server side to make sure that the client is free of encumbrances. Christian Schaller from Collabora posted about this a little while ago. Since then, the UI has been improved somewhat and some I/O issues have been fixed to the point where we felt comfortable enabling the BBC plugin (as well as the YouTube plugin) by default in Ubuntu 8.10. Here's a screenshot of the current interface. This is exciting stuff with a lot of potential. To try it out, run Applications -> Sound & Video -> Movie Player and select the "BBC" entry from the drop-down box labelled "Playlist". If you find bugs, please report them! Thu, 05 Mar 2009I've been a bit surprised by the strong positive response to my previous post. People generally seemed to think it was quite non-ranty; maybe I should clean the rust off my flamethrower. :-) My hope was that I'd be able to persuade people to change some practices, so I guess that's a good thing. Of course, there are many very smart people doing bug triage very well, and I don't want to impugn their fine work. Like its medical namesake, bug triage is a skilled discipline. While it's often repetitive, and there are lots of people showing up with similar symptoms, a triage nurse can really make a difference by spotting urgent cases, cleaning up some of the initial blood, and referring the patient quickly to a doctor for attention. Or, if a pattern of cases suddenly appears, a triage nurse might be able to warn of an incipient epidemic. [Note: I have no medical experience, so please excuse me if I'm talking crap here. :-)] The bug triagers who do this well are an absolute godsend; especially when they respond to repetitive tasks with tremendously useful pieces of automation like bughelper. The cases I have trouble with are more like somebody showing up untrained, going through everyone in the waiting room, and telling each of them that they just need to go home, get some rest, and stop complaining so much. Sometimes of course they'll be right, but without taking the time to understand the problem they're probably going to do more harm than good. Ian Jackson reminded me that it's worth mentioning the purpose of bug reports on free software: namely, to improve the software. The GNU Project has some advice to maintainers on this. I think sometimes we stray into regarding bug reports more like support tickets. In that case it would be appropriate to focus on resolving each case as quickly as possible, if necessary by means of a workaround rather than by a software change, and only bother the developers when necessary. This is the wrong way to look at bug reports, though. The reason that we needed to set up a bug triage community in Ubuntu was that we had a relatively low developer-to-package ratio and a very high user-to-developer ratio, and we were getting a lot of bug reports that weren't fleshed out enough for a developer to investigate them without spending a lot of time in back-and-forth with the reporter, so a number of people volunteered to take care of the initial back-and-forth so that good clear bug reports could be handed over to developers. This is all well and good, and indeed I encouraged it because I was personally finding myself unable to keep up with incoming bugs and actually fix anything at the same time. Somewhere along the way, though, some people got the impression that what we wanted was a first-line support firewall to try to defend developers from users, which of course naturally leads to ideas such as closing wishlist bugs containing ideas because obviously those important developers wouldn't want to be bothered by them, and closing old bugs because clearly they must just be getting in developers' way. Let me be clear about this now: I absolutely appreciate help getting bug reports into a state where I can deal with them efficiently, but I do not want to be defended from my users! I don't have a basis from which to state that all developers feel the same way, but my guess is that most do. Antti-Juhani Kaijanaho said he'd experienced most of these problems in Debian. I hadn't actually intended my post to go to Planet Debian - I'd forgotten that the "ubuntu" category on my blog goes there too, which generally I see as a feature, but if I'd remembered that I would have been a little clearer that I was talking about Ubuntu bug triage. If I had been talking about Debian bug triage I'd probably have emphasised different things. Nevertheless, it's interesting that at least one Debian (and non-Ubuntu) developer had experienced similar problems. Justin Dugger mentions a practice of marking duplicate bugs invalid that he has problems with. I agree that this is suboptimal and try not to do it myself. That said, this is not something I object to to the same extent. Given that the purpose of bugs is to improve the software, the real goal is to be able to spend more time fixing bugs, not to get bugs into the ideal state when the underlying problem has already been solved. If it's a choice between somebody having to spend time tracking down the exact duplicate bug number versus fixing another bug, I know which I'd take. Obviously, when doing this, it's worth apologising that you weren't able to find the original bug number, and explaining what the user can do if they believe that you're mistaken (particularly if it's a bug that's believed to be fixed); the stock text people often use for this doesn't seem informative enough to me. Sebastien Bacher commented that preferred bug triage practices differ among teams: for instance, the Ubuntu desktop team deals with packages that are very much to the forefront of users' attention and so get a lot of duplicate bugs. Indeed - and bug triagers who are working closely with the desktop team on this are almost certainly doing things the way the developers on the desktop team prefer, so I have no problem with that. The best advice I can give bug triagers is that their ultimate aim is to help developers, and so they should figure out which developers they need to work with and go and talk to them! That way, rather than duplicating work or being counterproductive, they can tailor their work to be most effective. Everybody wins. Mon, 02 Mar 2009I hate to say this, but often when somebody does lots of bug triage on a package I work on, I find it to be a net loss for me. I end up having to go through all the things that were changed, correct a bunch of them, occasionally pacify angry bug submitters, and all the rest of it, and often the benefits are minimal at best. I would very much like this not to be the case. Bug triage is supposed to help developers be more efficient, and I think most people who do bug triage are generally well-intentioned and eager to help. Accordingly, here is a series of mini-rants intended to have educational value.
(This post is inspired by this post on ArsGeek, hence the title. Thanks to Scott James Remnant for some of the ideas in this post.) I'll get to the details of ArsGeek's post in a moment, but really the more interesting part of it is the discussion of how we sometimes end up releasing software with (from various people's perspectives) serious bugs, a question of release management. As a member of the Ubuntu release team, I thought I'd respond to this and try to clarify what goes on. Release management strategiesFirstly, I know of no way to ensure a bug-free release of a system the size of a modern GNU/Linux distribution, with software coming from a huge variety of sources with all kinds of different QA standards, not to mention plenty of sources within the distribution itself where new bugs can be introduced. Indeed, ensuring releases free of serious bugs is rather more of an art than a science. What may be surprising is that, for a composite distribution of software from lots of sources, it doesn't actually seem to make a whole lot of difference to bug density whether you choose to whack all the bugs out before picking a release date, or just pick a release date up-front and tell everyone to aim for that (as long as people believe your release dates; more on this later). I can't offer hard evidence for this, only the gut feel of somebody with experience of both approaches, but it does seem to me to be the case. The idea of releasing "when it's ready" is a very appealing one. I have some experience here: I used to be one of Debian's release managers too, which is just about as far to that end of the scale as you get among GNU/Linux distributions. In theory, you put all the software into a big pot, stir it up, collect all the bugs, and at some point when it smells reasonably good you get everyone to whack away at the bugs in turn until they're all gone. Then you release. In theory, theory and practice are the same thing ... In practice, what happens is that there are a number of counterbalancing pressures. Developers don't want to be tied down waiting for all those other lazy developers who haven't fixed their bugs yet; users want the latest version of their favourite application which has some new and shiny feature; security support for the last release is getting harder as it gets older and the backport distance increases; people with new hardware want a new release that will support it; and so on. The longer you spend fixing bugs, the more the internal pressures show, and the harder it gets. Thus, even Debian compromises on this, and many of the bugs that are "fixed" shortly before release are in fact dealt with by removing leaf packages from the distribution, documenting workarounds, or simply deciding that they aren't release-critical. And this is only for the highest-severity bugs! Many other bugs, by straightforward necessity, are simply not important enough to hold up the release of the whole distribution. Now, Ubuntu opted for the time-based approach up front. You pick a date and you stick to it as if your life depended on it. Within that constraint, you figure out (read: guess) when new upstream software and major new features have to land in order to be able to fix the expected new bugs they introduce, and make case-by-case decisions on anything that slips past the intermediate deadlines you impose. You have to say "no" a lot, and you spend a lot of time in planning. Nowadays, this is familiar to most people: you don't delay a time-based release for new features. The hard bit comes when things go wrong, and then you find that you can't delay a time-based release to fix bugs either! If you slip your deadlines as a matter of course, then nobody will believe your release dates next time, and you'll start finding that people ignore the internal deadlines because "hey, they're not going to release on time anyway"; it all goes to pot very quickly. (We saw this in Debian: every time a published release date slipped, interest in putting in time to meet the next one diminished.) Thus you typically have a difficult choice: you can roll back to the last-known-good version (if this is even possible; often enough, interdependencies mean you'd end up rolling back a whole subsystem in order to get back to something that worked, and figuring out whether that's worth it can be harder than just fixing the bug to start with), or you can document the new bugs that have been introduced. Each choice will make somebody unhappy, as one group of people expects the latest-and-greatest software, and another expects stability. Neither group is intrinsically wrong, but you can't satisfy both of them in the presence of buggy software. Of course, there is a third choice: fix the bug already! In rather a lot of cases, we do, and we also spend a great deal of time triaging and organising bugs so that developers can focus on the most important ones first. In a time-based world, though, the clock is ticking and you have finite resources. If you have any, you can get your paid staff to focus on the really critical issues, and of course we do that; many of the Ubuntu team who are employed by Canonical pull some pretty long hours around release time. (As a side note, time-based releases seem to work a bit better when paid developers are involved because you can get away with doing this.) But all those paid staff tend to have extensive demands on their time, and so some things usually slip through the net. Ubuntu 8.04 decisionsSo, we have a bunch of tough decisions to make. I don't especially expect this to attract sympathy: after all, if it were easy, everyone would be doing it. Nevertheless, we have to make tough decisions all the time where there may not necessarily be a right answer, and they are an inevitable consequence of a time-based release process. When this kind of thing goes wrong, people rightly criticise us; as ArsGeek says, the buck stops with Ubuntu and Canonical as far as Ubuntu users are concerned. It often isn't as straightforward as it looks, though, since you don't get a practical demonstration of what would have gone wrong the other way round. If you look at it purely on the basis of bugs introduced, it seems clear that we should have held back on switching to GVFS (and GIO) and instead stuck with GNOME-VFS. The VFS layer is at the core of GNOME, though. Sticking with GNOME-VFS would mean either that we'd have to be using something that the upstream developers were no longer putting much effort into supporting, very probably resulting in other regressions, or we'd have had to ship GNOME 2.18 in Ubuntu 8.04 as we did in 7.10. This would be a big deal: the update in 8.10 would be fiendishly difficult because now we'd be behind, security support would be harder to achieve, software developers would find that software developed on other systems of around the same vintage might not even build on Ubuntu, and many users would be unhappy because they'd be missing out on new features introduced in GNOME 2.20. Instead, what we decided to do was to take the pain and do what we could to mitigate it, and, partly as a result of this, we handled the 8.04.1 point release somewhat differently from how we've handled similar point releases in the past. We set a date for 8.04.1 in advance, and a number of people worked solely towards that. Canonical sponsored work in GNOME to help iron out certain GVFS bugs that had already been raised as major omissions in the new framework. We agreed that 8.04.1 would be the first in a series of six-monthly point releases of 8.04 (out of phase with the main Ubuntu release cycle) so that users would be able to plan around it. There were various other major decisions in Ubuntu 8.04, some of which made headlines and some of which didn't. Here are a couple of examples with contrasting results:
Specific problemsArsGeek raised several specific annoyances, so I'll respond to those while I'm here.
In many of these cases, I noticed that nobody had actually filed a bug to tell us about the problem. While of course we do as much testing as we can internally, and you can always say "oh, that's obvious, they should have tested that one", we still don't have anything like the number of people you'd need to do complete testing on a full operating system, and we do have to rely on our users to report problems in the things they use. So, the last in my list of reasons why annoyances exist is that, every so often, developers don't notice them, and the users who do notice them don't report them! Sat, 12 Apr 2008Ubuntu's live CD installer, Ubiquity, needs to suppress desktop automounting while it's doing partitioning and generally messing about with mount points, otherwise its temporary mount points end up busy on unmount due to some smart-arse desktop component that decides to open a window for it. To date, it employs the following methods, each of which was sufficient at the time:
This is getting ridiculous. Dear desktop implementors: please pick a configuration mechanism and stick to it, and provide backward compatibility if you can't. This is not a rocket-science concept. I rather liked the
I hacked together a little timesaver for developers this morning: omni completion for Launchpad bugs in Vim's debchangelog mode. To use it, install vim 7.1-138+1ubuntu3 once it hits the mirrors, open up a debian/changelog file, type "LP: #", and hit Ctrl-X Ctrl-O. It'll think for a while and then give you a list of all the bugs open in Launchpad against the package in question, from which you can select to insert the bug number into your changelog. Here's a screenshot to make it clearer:
Thanks to Stefano Zacchiroli for doing the same for Debian bugs back in July. Tue, 03 Jan 2006Hot on the heels of Joey's tale of getting rid of base-config (the second stage of the installer) in Debian, we've now pretty much got rid of it in Ubuntu Dapper too. The upshot of this is that rather than asking a bunch of questions, installing the base system, and rebooting to install everything else, we now just install everything in one go and reboot into a completed system. This does mean that, if your system doesn't boot, you don't get to find out about it for a bit longer. However, it has lots of advantages in terms of speed (the much-maligned archive-copier mostly goes away), reducing code duplication (base-config had a bunch of infrastructure of its own which was done better in the core installer anyway), comprehensibility, and killing off some annoying bugs like #13561 (duplicate mirror questions in netboot installs), #15213 (second stage hangs if you skip archive-copier in the first stage), and #19571 (kernel messages scribble over base-config's UI). To go with Joey's Debian timeline, the Ubuntu history looks a bit like this:
Although it caused some friction, I'm glad that we did the first cuts of many of these things outside Debian and got to try things out before landing version-2-quality code in Debian. The end result is much nicer than the intermediate ones ever were. |
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