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Posted to users@wicket.apache.org by Bas Gooren <ba...@iswd.nl> on 2021/07/23 17:30:46 UTC
Possible bug / edge case found where page is not detached
Hi all,
Today I spent the better part of my day investigating a bug report
regarding a hibernate LazyInitializationException.
Since we use detaching models everywhere and (in general) never see such
issues anymore, this one was interesting :-)
After much debugging I found out what is happening.
We have a page which has a database model + links for prev/next item (in
the database).
When the users double-clicks on one of the links, the first click is OK,
and the second click throws a StalePageException during request cycle
processing.
So far, normal.
However, stepping through the wicket code, this is what happens:
1) Resolve to ListenerRequestHandler, execute it, throws StalePageException
2) exception mapper handles this and we execute a RenderPageRequestHandler,
which re-renders the page
3) the request cycle detaches, which delegates in part
to RequestHandlerExecutor.detach()
4) The handlers to detach are both handlers from step 1 and 2; During the
detach of ListenerRequestHandler, it initializes ListenerLogData, which (in
the PageLogData ctor) throws the StalePageException again!
5) The second handler (RenderPageRequestHandler) is not detached, thus all
models in the page are not detached
6) The user clicks on a link and boom, the models are all still attached
and there we get the LazyInitializationException
I think that (a) RequestHandlerExecutor.detach() should ensure all handlers
are detached, and (b) that failing to collect LogData should not stop the
detaching of a request handler.
What do you think?
I tried to make the simplest possible Quickstart to demonstrate this.
Weird stuff: on the homepage of the quick start, the page is properly
detached when a stale link is clicked;
On another (test) page, the page is not properly detached.
Steps to reproduce:
Run Quickstart
Click on “Test” link on homepage
Observe that the following is logged:
Model still attached? false
Page detaching
Now click on "Click me (stale link)!”
Now refresh the page (re-render)
Observe that the following is logged:
Model still attached? true
Page detaching
—> So the page was not detached
These steps don’t have the same result on the homepage. So my guess is
there is some relation to the fact that we are interacting with a stateful,
non-mounted page.
Met vriendelijke groet,
Kind regards,
Bas Gooren
Re: Possible bug / edge case found where page is not detached
Posted by "Locke, Jonathan (Luo Shibo)" <jo...@telenav.com>.
Now that is a stellar bug report.
________________________________
From: Bas Gooren <ba...@iswd.nl>
Sent: Sunday, July 25, 2021 12:06 AM
To: users@wicket.apache.org <us...@wicket.apache.org>; Sven Meier <sv...@meiers.net>
Subject: Re: Possible bug / edge case found where page is not detached
Hi Sven,
Done - https://issues.apache.org/jira/browse/WICKET-6908
Met vriendelijke groet,
Kind regards,
Bas Gooren
Op 24 juli 2021 bij 10:29:38, Sven Meier (sven@meiers.net) schreef:
Hi Bas,
that sounds like a bug.
Your quickstart didn't make it through the mailing list, would you please
attach it to a new Jira issue?
Thanks
Sven
Am 23. Juli 2021 19:30:46 MESZ schrieb Bas Gooren <ba...@iswd.nl>:
>Hi all,
>
>Today I spent the better part of my day investigating a bug report
>regarding a hibernate LazyInitializationException.
>Since we use detaching models everywhere and (in general) never see
>such
>issues anymore, this one was interesting :-)
>
>After much debugging I found out what is happening.
>
>We have a page which has a database model + links for prev/next item
>(in
>the database).
>When the users double-clicks on one of the links, the first click is
>OK,
>and the second click throws a StalePageException during request cycle
>processing.
>
>So far, normal.
>
>However, stepping through the wicket code, this is what happens:
>
>1) Resolve to ListenerRequestHandler, execute it, throws
>StalePageException
>2) exception mapper handles this and we execute a
>RenderPageRequestHandler,
>which re-renders the page
>3) the request cycle detaches, which delegates in part
>to RequestHandlerExecutor.detach()
>4) The handlers to detach are both handlers from step 1 and 2; During
>the
>detach of ListenerRequestHandler, it initializes ListenerLogData, which
>(in
>the PageLogData ctor) throws the StalePageException again!
>5) The second handler (RenderPageRequestHandler) is not detached, thus
>all
>models in the page are not detached
>6) The user clicks on a link and boom, the models are all still
>attached
>and there we get the LazyInitializationException
>
>I think that (a) RequestHandlerExecutor.detach() should ensure all
>handlers
>are detached, and (b) that failing to collect LogData should not stop
>the
>detaching of a request handler.
>
>What do you think?
>
>I tried to make the simplest possible Quickstart to demonstrate this.
>
>Weird stuff: on the homepage of the quick start, the page is properly
>detached when a stale link is clicked;
>On another (test) page, the page is not properly detached.
>
>Steps to reproduce:
>
>Run Quickstart
>Click on “Test” link on homepage
>Observe that the following is logged:
>
>Model still attached? false
>Page detaching
>
>Now click on "Click me (stale link)!”
>Now refresh the page (re-render)
>
>Observe that the following is logged:
>
>Model still attached? true
>Page detaching
>
>—> So the page was not detached
>
>These steps don’t have the same result on the homepage. So my guess is
>there is some relation to the fact that we are interacting with a
>stateful,
>non-mounted page.
>
>Met vriendelijke groet,
>Kind regards,
>
>Bas Gooren
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Re: Possible bug / edge case found where page is not detached
Posted by Bas Gooren <ba...@iswd.nl>.
Hi Sven,
Done - https://issues.apache.org/jira/browse/WICKET-6908
Met vriendelijke groet,
Kind regards,
Bas Gooren
Op 24 juli 2021 bij 10:29:38, Sven Meier (sven@meiers.net) schreef:
Hi Bas,
that sounds like a bug.
Your quickstart didn't make it through the mailing list, would you please
attach it to a new Jira issue?
Thanks
Sven
Am 23. Juli 2021 19:30:46 MESZ schrieb Bas Gooren <ba...@iswd.nl>:
>Hi all,
>
>Today I spent the better part of my day investigating a bug report
>regarding a hibernate LazyInitializationException.
>Since we use detaching models everywhere and (in general) never see
>such
>issues anymore, this one was interesting :-)
>
>After much debugging I found out what is happening.
>
>We have a page which has a database model + links for prev/next item
>(in
>the database).
>When the users double-clicks on one of the links, the first click is
>OK,
>and the second click throws a StalePageException during request cycle
>processing.
>
>So far, normal.
>
>However, stepping through the wicket code, this is what happens:
>
>1) Resolve to ListenerRequestHandler, execute it, throws
>StalePageException
>2) exception mapper handles this and we execute a
>RenderPageRequestHandler,
>which re-renders the page
>3) the request cycle detaches, which delegates in part
>to RequestHandlerExecutor.detach()
>4) The handlers to detach are both handlers from step 1 and 2; During
>the
>detach of ListenerRequestHandler, it initializes ListenerLogData, which
>(in
>the PageLogData ctor) throws the StalePageException again!
>5) The second handler (RenderPageRequestHandler) is not detached, thus
>all
>models in the page are not detached
>6) The user clicks on a link and boom, the models are all still
>attached
>and there we get the LazyInitializationException
>
>I think that (a) RequestHandlerExecutor.detach() should ensure all
>handlers
>are detached, and (b) that failing to collect LogData should not stop
>the
>detaching of a request handler.
>
>What do you think?
>
>I tried to make the simplest possible Quickstart to demonstrate this.
>
>Weird stuff: on the homepage of the quick start, the page is properly
>detached when a stale link is clicked;
>On another (test) page, the page is not properly detached.
>
>Steps to reproduce:
>
>Run Quickstart
>Click on “Test” link on homepage
>Observe that the following is logged:
>
>Model still attached? false
>Page detaching
>
>Now click on "Click me (stale link)!”
>Now refresh the page (re-render)
>
>Observe that the following is logged:
>
>Model still attached? true
>Page detaching
>
>—> So the page was not detached
>
>These steps don’t have the same result on the homepage. So my guess is
>there is some relation to the fact that we are interacting with a
>stateful,
>non-mounted page.
>
>Met vriendelijke groet,
>Kind regards,
>
>Bas Gooren
Re: Possible bug / edge case found where page is not detached
Posted by Sven Meier <sv...@meiers.net>.
Hi Bas,
that sounds like a bug.
Your quickstart didn't make it through the mailing list, would you please attach it to a new Jira issue?
Thanks
Sven
Am 23. Juli 2021 19:30:46 MESZ schrieb Bas Gooren <ba...@iswd.nl>:
>Hi all,
>
>Today I spent the better part of my day investigating a bug report
>regarding a hibernate LazyInitializationException.
>Since we use detaching models everywhere and (in general) never see
>such
>issues anymore, this one was interesting :-)
>
>After much debugging I found out what is happening.
>
>We have a page which has a database model + links for prev/next item
>(in
>the database).
>When the users double-clicks on one of the links, the first click is
>OK,
>and the second click throws a StalePageException during request cycle
>processing.
>
>So far, normal.
>
>However, stepping through the wicket code, this is what happens:
>
>1) Resolve to ListenerRequestHandler, execute it, throws
>StalePageException
>2) exception mapper handles this and we execute a
>RenderPageRequestHandler,
>which re-renders the page
>3) the request cycle detaches, which delegates in part
>to RequestHandlerExecutor.detach()
>4) The handlers to detach are both handlers from step 1 and 2; During
>the
>detach of ListenerRequestHandler, it initializes ListenerLogData, which
>(in
>the PageLogData ctor) throws the StalePageException again!
>5) The second handler (RenderPageRequestHandler) is not detached, thus
>all
>models in the page are not detached
>6) The user clicks on a link and boom, the models are all still
>attached
>and there we get the LazyInitializationException
>
>I think that (a) RequestHandlerExecutor.detach() should ensure all
>handlers
>are detached, and (b) that failing to collect LogData should not stop
>the
>detaching of a request handler.
>
>What do you think?
>
>I tried to make the simplest possible Quickstart to demonstrate this.
>
>Weird stuff: on the homepage of the quick start, the page is properly
>detached when a stale link is clicked;
>On another (test) page, the page is not properly detached.
>
>Steps to reproduce:
>
>Run Quickstart
>Click on “Test” link on homepage
>Observe that the following is logged:
>
>Model still attached? false
>Page detaching
>
>Now click on "Click me (stale link)!”
>Now refresh the page (re-render)
>
>Observe that the following is logged:
>
>Model still attached? true
>Page detaching
>
>—> So the page was not detached
>
>These steps don’t have the same result on the homepage. So my guess is
>there is some relation to the fact that we are interacting with a
>stateful,
>non-mounted page.
>
>Met vriendelijke groet,
>Kind regards,
>
>Bas Gooren