diff --git a/core/src/main/java/hudson/model/AbstractItem.java b/core/src/main/java/hudson/model/AbstractItem.java
index 2aa752f57b..15de44afa6 100644
--- a/core/src/main/java/hudson/model/AbstractItem.java
+++ b/core/src/main/java/hudson/model/AbstractItem.java
@@ -603,7 +603,13 @@ public abstract class AbstractItem extends Actionable implements Item, HttpDelet
             }
 
             // try to reflect the changes by reloading
-            new XmlFile(Items.XSTREAM, out.getTemporaryFile()).unmarshal(this);
+            Object o = new XmlFile(Items.XSTREAM, out.getTemporaryFile()).unmarshal(this);
+            if (o!=this) {
+                // ensure that we've got the same job type. extending this code to support updating
+                // to different job type requires destroying & creating a new job type
+                throw new IOException("Expecting "+this.getClass()+" but got "+o.getClass()+" instead");
+            }
+
             Items.updatingByXml.set(true);
             try {
                 onLoad(getParent(), getRootDir().getName());
diff --git a/test/src/test/groovy/hudson/model/AbstractProjectTest.groovy b/test/src/test/groovy/hudson/model/AbstractProjectTest.groovy
index a17d5965df..2cb0198a49 100644
--- a/test/src/test/groovy/hudson/model/AbstractProjectTest.groovy
+++ b/test/src/test/groovy/hudson/model/AbstractProjectTest.groovy
@@ -27,7 +27,8 @@ import com.gargoylesoftware.htmlunit.ElementNotFoundException
 import com.gargoylesoftware.htmlunit.FailingHttpStatusCodeException;
 import com.gargoylesoftware.htmlunit.HttpMethod;
 import com.gargoylesoftware.htmlunit.WebRequestSettings
-import com.gargoylesoftware.htmlunit.html.HtmlPage;
+import com.gargoylesoftware.htmlunit.html.HtmlPage
+import hudson.maven.MavenModuleSet;
 import hudson.security.*;
 import hudson.tasks.BuildTrigger;
 import hudson.tasks.Shell;
@@ -44,7 +45,7 @@ import hudson.util.StreamTaskListener;
 import hudson.util.OneShotEvent
 import jenkins.model.Jenkins;
 import org.acegisecurity.context.SecurityContext;
-import org.acegisecurity.context.SecurityContextHolder;
+import org.acegisecurity.context.SecurityContextHolder
 import org.jvnet.hudson.test.HudsonTestCase
 import org.jvnet.hudson.test.Bug;
 import org.jvnet.hudson.test.MemoryAssert;
@@ -515,4 +516,38 @@ public class AbstractProjectTest extends HudsonTestCase {
         assert jenkins.getItem("regular")!=null;
         assert jenkins.getItem("secret")!=null;
     }
+
+
+    /**
+     * Trying to POST to config.xml by a different job type should fail.
+     */
+    public void testConfigDotXmlSubmissionToDifferentType() {
+        jenkins.crumbIssuer = null
+        def p = createFreeStyleProject()
+
+        HttpURLConnection con = postConfigDotXml(p, "<maven2-moduleset />")
+
+        // this should fail with a type mismatch error
+        // the error message should report both what was submitted and what was expected
+        assert con.responseCode == 500
+        def msg = con.errorStream.text
+        println msg
+        assert msg.contains(FreeStyleProject.class.name)
+        assert msg.contains(MavenModuleSet.class.name)
+
+        // control. this should work
+        con = postConfigDotXml(p, "<project />")
+        assert con.responseCode == 200
+    }
+
+    private HttpURLConnection postConfigDotXml(FreeStyleProject p, String xml) {
+        HttpURLConnection con = new URL(getURL(), "job/${p.name}/config.xml").openConnection()
+        con.requestMethod = "POST"
+        con.setRequestProperty("Content-Type", "application/xml")
+        con.doOutput = true
+        con.outputStream.withStream { s ->
+            s.write(xml.bytes)
+        }
+        return con
+    }
 }