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https://issues.apache.org/jira/browse/WICKET-5911?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Martin Grigorov updated WICKET-5911:
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Fix Version/s: (was: 7.0.0)
7.0.0-M6
> Re-rendering page after exception in render phase does not call
> onBeforeRender()
> --------------------------------------------------------------------------------
>
> Key: WICKET-5911
> URL: https://issues.apache.org/jira/browse/WICKET-5911
> Project: Wicket
> Issue Type: Bug
> Components: wicket
> Affects Versions: 7.0.0-M6
> Reporter: Michal Kara
> Assignee: Sven Meier
> Priority: Minor
> Fix For: 6.20.0, 7.0.0-M6
>
>
> (I sent this to the mailing list originaly, Sven Meier replied this is
> probably a bug and requested creating a JIRA issue for it.)
> I got page with structure like:
> - Page
> +- ListView -- items
> \ - Footer panel
> Now the scenario (heavily simplified):
> One of the items in ListView gets exception from backend during
> onInitialize(). Required behavior in this case is to keep user on the page
> and replace ListView with a panel stating "Sorry, backend outage".
> So I catch the backend exception using aspect, replace view in the structure
> with the message panel and throw NonResettingRestartException to restart
> rendering the page.
> Page is rendered and seems OK, BUT I realize onBeforeRender() of Footer panel
> is never called.
> I debugged it and found the cause:
> ListView adds items in onPopulate() method which is called from
> onBeforeRender(). When page starts rendering, its onBeforeRender() is called.
> Page does:
> setFlag(FLAG_PREPARED_FOR_RENDER, true);
> and calls onBeforeRenderChildren(). This calls onBeforeRender() of ListView,
> causes exception, so that onBeforeRender() of the footer is not called this
> time.
> When second rendering is attempted, call flow gets to internalBeforeRender()
> of the page component. There is check:
> if ((determineVisibility()) && !getFlag(FLAG_RENDERING) &&
> !getFlag(FLAG_PREPARED_FOR_RENDER)) {
> ...
> onBeforeRender();
> ...
> }
> But since FLAG_PREPARED_FOR_RENDER is set from previous attempt,
> onBeforeRender() of the page is not called (again) which means
> onBeforeRender() of the children is not called.
> I found that if I call
> markRendering(false);
> on the page before throwing the NonResettingRestartException, all goes well.
> But I am quite uneasy about this solution, so I have two questions:
> 1) Cannot this cause some unforeseen troubles? (Supposing my components are
> correctly written so that their onBeforeRender() / onConfigure() /
> onAfterRender() procedures can be safely called multiple times.)
> 2) Should not Wicket itself reset the FLAG_PREPARED_FOR_RENDER when response
> restarting exception is caught and processed?
> I created a Wicket quickstart project demonstrating the bug here:
> http://lemming.hofyland.cz/restartbug.zip
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