No build.xml is created when warnings plugin is used in combination with deactivated maven plugin

The Warnings Plug-in doesn't seem to work correctly if the maven plugin is deactivated. In our case it prevented the creation of the build.xml at the end of a build. As long as Jenkins is running, all builds and their history are shown correctly, but after a restart, Jenkins can't get the necessary informations to build up the history due to missing build.xml. This results in a faulty build history (no past builds are shown).

To reproduce, follow these steps:
1. Deactivate the maven plugin
2. Make sure you have the Warnings and msbuild plugin installed
3. Create a job which contains a msbuild step (we used msbuild 4.0)
4. Create a post buildstep "Scan for compiler warnings" and use "Scan console log" with "msbulid parser"

In our case, with above setup, no build.xml was created if:

• maven was deactivated AND warnings was turned on

In other combinations (maven on/off, warnings on/off) a build.xml was created hence the problem lies within the Warnings plugin and not maven.

In Attachment you find a minimal example (no_buildXml_minExample.jpg) where you can reproduce the bug by turning maven on/off. In the example you can see that Build #2 is missing - this was done with deactivated maven.

no_buildXml_plugins.jpg shows our installed Jenkins plugins in case there are other unknown side effects.