[jbossseam-issues] [JBoss JIRA] Reopened: (JBSEAM-2597) Exception handling - JSF swallows exceptions in certain phases

[Christian Bauer (JIRA)]

     [ http://jira.jboss.com/jira/browse/JBSEAM-2597?page=all ]

Christian Bauer reopened JBSEAM-2597:
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I can't reproduce the issue Pete mentioned, Facelets does not swallow an exception on rendered="{bindingThrowsException}", at least not during a regular GET request.

However, the JSF RI + Seam swallow exceptions in two other situations:

1. Exception on POSTback thrown in UPDATE MODEL in a value-binding setter. This is converted, without messages in the log, to a JSF validation error message that says "Error writing 'formContent' on type org.jboss.seam.wiki.core.action.DocumentHome_$$_javassist_29". No stacktrace or other hint in the log.

2. Exception on POSTback from an Ajax4JSF request thrown in UPDATE MODEL in a value binding setter. This is also converted, but if you do not reRender the message section of your page, nothing will appear on the page but this in the log: INFO  [javax.enterprise.resource.webcontainer.jsf.lifecycle] WARNING: FacesMessage(s) have been enqueued, but may not have been displayed.
sourceId=docEditForm:previewSwitch[severity=(ERROR 2), summary=(/docEdit_d.xhtml @191,158 value="#{documentHome.enabledPreview}": Error writing 'enabledPreview' on type org.jboss.seam.wiki.core.action.DocumentHome_$$_javassist_20), detail=(/docEdit_d.xhtml @191,158 value="#{documentHome.enabledPreview}": Error writing 'enabledPreview' on type org.jboss.seam.wiki.core.action.DocumentHome_$$_javassist_20)]

Obviously 1. and 2. are connected, so this is, as hinted in the original issue summary, about JSF swallowing exceptions in UPDATE MODEL and converting them into weak message that might be displayed in different places.

Now, I don't know why the JSF RI authors decided that a RuntimeException can be ignored and that processing can continue after the UPDATE MODEL phase clearly failed. Even if we can't do anything about this in Seam, we should leave this issue open until this is resolved in one way or another.

Note: I've already updated Seam with Petes new JDK/log4j logging bridge, so that INFO message that says "WARNING" is just... wrong.



> Exception handling - JSF swallows exceptions in certain phases
> --------------------------------------------------------------
>
>                 Key: JBSEAM-2597
>                 URL: http://jira.jboss.com/jira/browse/JBSEAM-2597
>             Project: JBoss Seam
>          Issue Type: Feature Request
>          Components: Core
>            Reporter: Shane Bryzak
>             Fix For: 2.1.0.GA
>
>
> I can't reproduce this right now but I'm sure I spent several hours
> with a debugger only to find out that I had a typo in a value binding
> and that the exception was completely swallowed during an early JSF
> phase (UPDATE MODEL probably). There was nothing in the log, the
> action phase just never executed. This is a major issue (obviously)
> for another subtle reason: Beginners have trouble understanding the
> JSF lifecycle and processing phases - I know I did. You begin to hate
> JSf when you don't understand why a certain phase does not execute.
> I'd start reproducing it by generating an NPE in a value binding
> setter, that should do it.

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