[
https://issues.apache.org/jira/browse/MYFACES-3962?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14389650#comment-14389650
]
Leonardo Uribe commented on MYFACES-3962:
-----------------------------------------
I have notice the issue dissapear if you do something to change id according to
the row like this:
<c:forEach var="x" items="#{fn:split('a b c d e', ' ')}">
<h:outputText id="some-id#{x}" value="#{x}"/>,
</c:forEach>
The problem with generate new ids here is the state. If you add a value in the
middle of the c:forEach items, the state will not be correctly assigned to the
row, because since start there is no association between the element and the
state.
Enforce the syntax to add something else to the id is preferred, because the
state and the ids are consistent. There is also a performance problem, because
to generate new ids, if they are duplicated requires check the duplicate for
every component id, and that kind of calculation does not scale well. It
degrades the algorithm from linear to exponential, not to mention the other
nasty issues related to the state.
There is also the consideration for tags like f:ajax, which points to the id of
a component. If you generate an id in that part, f:ajax stops working, because
the right component will not be found.
I personally prefer a duplicate id exception, because there is a workaround
that is just trivial and it is compatible with both implementations. I'll close
this issue as won't fix. Thanks for the report.
> Duplicate ID exception thrown while iterating with c:forEach
> ------------------------------------------------------------
>
> Key: MYFACES-3962
> URL: https://issues.apache.org/jira/browse/MYFACES-3962
> Project: MyFaces Core
> Issue Type: Bug
> Components: General
> Affects Versions: 2.2.7
> Reporter: Mircea Toma
> Attachments: test.war
>
>
> A duplicate ID exception is thrown when iterating over a collection/array
> with c:forEach. The exception occurs only when the enclosed components have
> an ID assigned.
--
This message was sent by Atlassian JIRA
(v6.3.4#6332)
