Bug 2146 - NullReferenceException when calling Remove() extension method
Summary: NullReferenceException when calling Remove() extension method
Alias: None
Product: Class Libraries
Classification: Mono
Component: System.XML ()
Version: 2.10.x
Hardware: Macintosh Mac OS
: --- normal
Target Milestone: Untriaged
Assignee: Bugzilla
Depends on:
Reported: 2011-11-21 19:52 UTC by Marc Gallagher
Modified: 2012-01-19 05:53 UTC (History)
2 users (show)

Is this bug a regression?: ---
Last known good build:

Example code (730 bytes, text/plain)
2011-11-21 19:52 UTC, Marc Gallagher

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Description Marc Gallagher 2011-11-21 19:52:49 UTC
Created attachment 924 [details]
Example code

The MSDN documentation for System.Xml.Linq.Extensions.Remove() (http://msdn.microsoft.com/en-us/library/bb357554(v=VS.90).aspx) has the following in the remarks section:

"This method uses snapshot semantics—that is, it copies the nodes in the source collection to a List<T> before disconnecting them from their parents. This is required to avoid issues with mixed imperative/declarative code."

However, Mono's version does not take similar precautions which can lead to the enumerator being placed in an inconsistent state. This is especially noticeable when using NodesBeforeSelf() and NodesAfterSelf().

The attached code fragment demonstrates the issue.
Comment 1 Atsushi Eno 2012-01-19 05:53:01 UTC
That's a good catch. Fixed in git master df47a23. Thanks for the report.