This only occurs during excessive log output, where a log is usually less than 1MB, in this failure the (text) log was in excess of 20GB.

Exception raised during template rendering: null
java.lang.NullPointerException at
java.io.File.(File.java:277) at
sun.reflect.GeneratedConstructorAccessor881.newInstance(Unknown Source) at
sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45) at
java.lang.reflect.Constructor.newInstance(Constructor.java:526) at
org.codehaus.groovy.reflection.CachedConstructor.invoke(CachedConstructor.java:77) at
org.codehaus.groovy.runtime.callsite.ConstructorSite$ConstructorSiteNoUnwrapNoCoerce.callConstructor(ConstructorSite.java:102) at
org.codehaus.groovy.runtime.callsite.AbstractCallSite.callConstructor(AbstractCallSite.java:190) at
SimpleTemplateScript39.run(SimpleTemplateScript39.groovy:58) at
groovy.text.SimpleTemplateEngine$SimpleTemplate$1.writeTo(SimpleTemplateEngine.java:165) at
groovy.text.SimpleTemplateEngine$SimpleTemplate$1.toString(SimpleTemplateEngine.java:177) at
hudson.plugins.emailext.plugins.content.ScriptContent.renderTemplate(ScriptContent.java:216) at
hudson.plugins.emailext.plugins.content.ScriptContent.evaluate(ScriptContent.java:85) at
org.jenkinsci.plugins.tokenmacro.DataBoundTokenMacro.evaluate(DataBoundTokenMacro.java:189) at
org.jenkinsci.plugins.tokenmacro.TokenMacro.expand(TokenMacro.java:182) at
org.jenkinsci.plugins.tokenmacro.TokenMacro.expandAll(TokenMacro.java:233) at
hudson.plugins.emailext.plugins.ContentBuilder.transformText(ContentBuilder.java:72) at
hudson.plugins.emailext.ExtendedEmailPublisher.getContent(ExtendedEmailPublisher.java:659) at
hudson.plugins.emailext.ExtendedEmailPublisher.createMail(ExtendedEmailPublisher.java:538) at
hudson.plugins.emailext.ExtendedEmailPublisher.sendMail(ExtendedEmailPublisher.java:306) at
hudson.plugins.emailext.ExtendedEmailPublisher._perform(ExtendedEmailPublisher.java:297) at
hudson.plugins.emailext.ExtendedEmailPublisher.perform(ExtendedEmailPublisher.java:244) at
hudson.tasks.BuildStepMonitor$1.perform(BuildStepMonitor.java:20) at
hudson.model.AbstractBuild$AbstractBuildExecution.perform(AbstractBuild.java:779) at
hudson.model.AbstractBuild$AbstractBuildExecution.performAllBuildSteps(AbstractBuild.java:726) at
hudson.model.Build$BuildExecution.cleanUp(Build.java:195) at
hudson.model.Run.execute(Run.java:1788) at
hudson.model.FreeStyleBuild.run(FreeStyleBuild.java:43) at
hudson.model.ResourceController.execute(ResourceController.java:98) at
hudson.model.Executor.run(Executor.java:408)