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https://issues.apache.org/jira/browse/ISIS-1269?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15028848#comment-15028848
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ASF subversion and git services commented on ISIS-1269:
-------------------------------------------------------
Commit 7798ab807d6cd0751d84eb61910021b8ca5794e0 in isis's branch
refs/heads/master from [~danhaywood]
[ https://git-wip-us.apache.org/repos/asf?p=isis.git;h=7798ab8 ]
ISIS-1269: ignore any null objects in list (this can happen if they have for
example just been deleted).
Really the list being rendered shouldn't include the object about to be
deleted; in the isis-app-todoapp there was a programming error:
public List<ToDoItem> delete() {
// obtain title first, because cannot reference object after deleted
final String title = container.titleOf(this);
final List<ToDoItem> returnList = actionInvocationContext.isLast() ?
toDoItems.notYetComplete() : null;
// there's actually a bug in this method; shouldn't be returning the
current object in the list if just deleted.
// however, ISIS-1269 transparently handles this and won't attempt to
render a deleted object.
container.removeIfNotAlready(this);
container.informUser(
TranslatableString.tr("Deleted {title}", "title", title),
this.getClass(), "delete");
return returnList;
}
On the other hand, in the more general case some *other* user might have just
deleted the object, in which case this fix will also support that case.
> Deleting an object from a list can cause NPE when that list is re-rendered.
> ---------------------------------------------------------------------------
>
> Key: ISIS-1269
> URL: https://issues.apache.org/jira/browse/ISIS-1269
> Project: Isis
> Issue Type: Improvement
> Components: Core
> Affects Versions: 1.10.0
> Reporter: Dan Haywood
> Assignee: Dan Haywood
> Priority: Minor
> Fix For: 1.11.0
>
>
> For example, in the todoapp the home page displays all the todo items, not
> yet completed vs completed.
> If select "Buy Milk" (when not complete) and delete it, then the NPE is
> thrown.
> This is ultimately because the list returned from ToDoItem#delete() is stale:
> {code}
> public List<ToDoItem> delete() {
> // obtain title first, because cannot reference object after deleted
> final String title = container.titleOf(this);
> final List<ToDoItem> returnList = actionInvocationContext.isLast() ?
> toDoItems.notYetComplete() : null;
> container.removeIfNotAlready(this);
> container.informUser(
> TranslatableString.tr("Deleted {title}", "title", title),
> this.getClass(), "delete");
> return returnList;
> }
> {code}
> It ought not to return the current object about to be deleted.
> Even so, we can handle this application programming error easily enough, by
> filtering out any null objects.
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