Re: [p2-dev] Feature patch and GC

[James D Miles <jdmiles@xxxxxxxxxx>]

I can't see how a different icon will help this. What we have is a feature and feature patch that are locked together. This simple case only had one plugin attached to the feature but there could be more. So that is why I say neither the feature or patch is viable without the other. But the UI does not represent that accurately.

Since we don't allow the display of prior versions of IUs in the UI or allow selection and reversion of specific features it would seem that we shouldn't be able to expect to uninstall the patch and get to the original feature. Unfortunately this patch thing has been linked to our hotfix mechanism and it is expected that it can be backed out.

I am also wondering if we are making policy decisions in the code. For instance we use to have a policy on how many prior versions to leave on the system. Another way to look at p2 is we only support the keeping of resolved versions of plugins -- no less, no more.

I will put this on my issue list to work later.

Pascal Rapicault ---04/07/2009 08:21:38 PM---It is true that the UI could probably show things a bit differently. Maybe simply showing the feature patch with a specific ico

From:	Pascal Rapicault <Pascal_Rapicault@xxxxxxxxxx>
To:	P2 developer discussions <p2-dev@xxxxxxxxxxx>
Cc:	p2-dev@xxxxxxxxxxx, p2-dev-bounces@xxxxxxxxxxx
Date:	04/07/2009 08:21 PM
Subject:	Re: [p2-dev] Feature patch and GC

---

It is true that the UI could probably show things a bit differently. Maybe simply showing the feature patch with a specific icon could already help. Please open an enhancement request about that.
As for the GC behavior, this is a controversial issue. Typically in the product scenarios that I have seen, the patches are here to stay and keeping the old plug-ins would probably result in comments that are just at the opposite of yours :). Also, p2 patches can actually patch any dependency and as a result the size of the thing being "patched out" can be non-trivial such that you would not want to keep it.
To get out of the business of tweaking the GC for every possible use, the GC is extensible and one could implement the behaviour you are after.

HTH

PaScaL

James D Miles ---04/07/2009 11:36:18 AM---It seems to me that the garbage collector is too aggressive in certain situations. Here is the scena

From:	James D Miles <jdmiles@xxxxxxxxxx>
To:	p2-dev@xxxxxxxxxxx
Date:	04/07/2009 11:36 AM
Subject:	[p2-dev] Feature patch and GC

---

It seems to me that the garbage collector is too aggressive in certain situations. Here is the scenario.
fA100 + pA100 installed
feature patch fp100 patches fA100 with pA101
Install fp100 now fA and platform are running with pA101

Both fA and fp are shown in p2 UI
Both fA100, fp100, pA100, and pA101 are on file system.
pA101 is loaded into OSGi

Now
- remove preferences for repositories used above.
- run garbage collector
- Both fA and fp are shown in p2 UI
- Both fA, fp, pA100, and pA101 are on file system. (pA100 is removed from file system)
- pA101 is loaded into OSGi

The garbage collector has removed pA100.
Everything needed to run the system is available.

If a user now attempts to uninstall the patch or revert we will get an error

Cannot complete the install because one or more required items could not be found.
Software currently installed: com.test.G11.feature.HelloWorld.feature.group 1.0.0
Missing requirement: com.test.G11.feature.HelloWorld.feature.group 1.0.0 requires 'com.test.G11.plugin.HelloWorld [1.0.0]' but it could not be found

So the message is correct but I think from the users standpoint it is strange. The system clear shows in the p2 UI that fA100 is available and installed but it is also telling him it is not fully installed.

To me it is a bug to show the feature/IU installed but not have the artifacts available. Comments?

It likely would be easier to fix the aggressive GC than to somehow help the user locate the missing repository._______________________________________________
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