Bug 14149 - XElement.Save with OmitDuplicateNamespaces creates duplicate namespaces, produces invalid XML
Summary: XElement.Save with OmitDuplicateNamespaces creates duplicate namespaces, prod...
Alias: None
Product: Class Libraries
Classification: Mono
Component: System.XML ()
Version: unspecified
Hardware: PC Windows
: --- normal
Target Milestone: Untriaged
Assignee: Bugzilla
Depends on:
Reported: 2013-08-21 12:43 UTC by Adam Kemp
Modified: 2015-03-17 06:49 UTC (History)
2 users (show)

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

Sample project (15.05 KB, application/x-download)
2013-08-21 12:43 UTC, Adam Kemp

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Description Adam Kemp 2013-08-21 12:43:19 UTC
Created attachment 4685 [details]
Sample project

This was discovered using Xamarin.Android 4.8.1 with Mono 3.2. When you use the SaveOptions.OmitDuplicateNamespaces flag with System.Xml.Linq.XElement.Save it actually causes every xmlns attribute to be duplicated, like so:

<element xmlns="foo" xmlns="foo" />

This causes parsing (using a XmlReader) to fail with a System.Xml.XmlException: "Attribute name and qualified name must be identical."

To reproduce this run the attached android project and click the button. You will get an exception. If you comment out the line setting the OmitDuplicateNamespaces flag then the crash will go away. The application also prints out the modified XML so you can see how it is being corrupted.
Comment 1 Atsushi Eno 2015-03-17 06:49:03 UTC
Now System.Xml.Linq is based on referencesource this does not reproduce anymore.