The Object Teams Blog

Adding team spirit to your objects.

A Short Train Ride

with 2 comments

Less than a week ago I happily announced that Object Teams is on the Indigo Train.
Much water has gone under the bridge since then and the above statement is history.

Events where triggered by what was actually a little bug in the b3 aggregator. Only by way of this bug some people noticed that there was a ”’patch feature”’ inside the repository, i.e., a feature (“Object Teams Patch for JDT/Core”) that replaces the jdt.core plugin with a variant.

One part of me is very happy this bug occurred because finally an issue got the attention I had tried to raise at various occasions before. The lesson is:

Installing stuff with p2 may do other things than just adding new functionality, it may change existing stuff.

(see this post, e.g.).

The other part of me got very worried because during that debate some harsh statements occurred that would effectively amount to excluding Object Teams from Eclipse.org. That’s a little more attention than I had intended. As in any heated debate some of the arguments sounded to me more like ideology than anything that could possibly be discussed open-mindedly.

I had mixed feelings regarding the technical scope: the outcry only banned one specific technology: patch features. I don’t see how the goal to protect a project’s bits and bytes against influence from other projects can be achieved without also discussing: access to internal, byte-code weaving and – worst of all, I believe – reflection. To be perfectly open: Object Teams uses all these techniques except for reflection. Personally, I would even argue for banning projects that do use setAccessible(true), but that’s not a realistic option because then quite likely the whole Train would dissolve into a mist.

I am actually guilty of a technical simplification during this debate: I focused too much on the idea that a user would explicitly select features to install, not accounting for the possibility that the jdt.core plugin can well be pulled in invisibly due to dependencies among plugins. So, yes, if Object Teams would still be in the repository, and if a user installed a package without the JDT and if that user did never select to install the JDT and if that user selects another feature that implicitly requires the jdt.core plugin, then that user would unexpectly install the OT variant of the jdt.core. I agree that this is not ideal. I personally would have been happy to take this risk because I know how thoroughly the OT variant is tested for compatibility. And for the remaining minuscule risk I would have been happy to promise same-day fixes. But risk assessment naturally depends on perspective and I understand that others come to different conclusions when weighing the issues.

From two days distance I can already laugh at one implication of the central argument, paraphrased as: the JDT/Core team must be protected against harmful actions from the OT team. When spelling this out in names, one of the sentences reads: “Stephan Herrmann must be protected against harmful actions by Stephan Herrmann”. I should really be careful, because I’ll never be able to escape him!

Where to go?

  • As we’re banned from the Train, I willed hurriedly book a plane ticket to Indigo. Make sure we come by a Graduation office on the way.
  • I do hope that bug 316702 get’s sufficient attention now. Seriously: if you are so detrimentally determined about patch features, then the UI must report it. And if it reports this, it might as well report other techniques that have similar effects!
  • I appreciate any offers for helping OT/J towards a solution that avoids replacing a plugin. As of today and after more than seven years of looking at this, I see no way how this can be done, but that doesn’t mean we shouldn’t try still harder.
Unfortunately, the debate consumed all the time and energy I had planned for preparing a presentation at the EclipseCON Audition. However, Lynn finally made my day by letting me know that my submission is the lucky #42. So I’m making progress towards my all-seasons Eclipse collection 🙂
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Written by Stephan Herrmann

November 18, 2010 at 14:32

Posted in Eclipse, Object Teams, OTDT

Tagged with , , ,

2 Responses

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  1. >From two days distance I can already laugh at one >implication of the central argument, paraphrased as: >the JDT/Core team must be protected against harmful >actions from the OT team.

    It’s unfortunate you got that impression, because I didn’t see that anywhere in the discussion. For most people I think the central argument was, if a consumer wants X, they should get X and not X’. This is not a qualitative statement about which is better, but rather a statement about the consumer being able to control and predict what software they obtain.

    The exact same problem goes in the other direction too – if a consumer really wants X’, they will also be disappointed if through the magic of dependency resolution they are given X instead. More concretely, if someone installing Object Teams was given the wrong (original) copy of JDT core they will also be broken.

    John Arthorne

    November 18, 2010 at 22:22

  2. John, your comment was automatically classified as spam, that’s why it didn’t show up.

    As done also on the bug, I can only apologize for this over-reaction.

    As mentioned in the post it took me a while to figure out *how* exactly the wrong plugin could be installed, I was too much focused on feature-to-plugin dependencies only, but I’ve learned.

    Ideally, the OT variant of JDT/Core will be fully compatible with the original (which can never be true in the opposite direction), but I shouldn’t even think of throwing this experiment at thousands of consumers of Indigo. Such risk would be way over my head.

    Therefor let’s hope we make good progress on bug 330534.

    stephan

    November 19, 2010 at 21:35


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