It seems that Idea recently started to provide Spock method templates out of box (they are available in the plain installation of Idea 133.79) which causes following exception on startup after the Spock plugin is installed. Probably it would be enough to not provide file template in the plugin version for Idea 13.
Assertion failed: Duplicate bundled template Spock SetUp Method.groovy
java.lang.Throwable
at com.intellij.openapi.diagnostic.Logger.assertTrue(Logger.java:141)
at com.intellij.ide.fileTemplates.impl.FTManager.a(FTManager.java:191)
at com.intellij.ide.fileTemplates.impl.FTManager.addDefaultTemplate(FTManager.java:182)
at com.intellij.ide.fileTemplates.impl.FileTemplatesLoader.a(FileTemplatesLoader.java:186)
at com.intellij.ide.fileTemplates.impl.FileTemplatesLoader.a(FileTemplatesLoader.java:147)
at com.intellij.ide.fileTemplates.impl.FileTemplatesLoader.<init>(FileTemplatesLoader.java:89)
at com.intellij.ide.fileTemplates.impl.ExportableFileTemplateSettings.<init>(ExportableFileTemplateSettings.java:54)
(...)
Fixed with 416dc02. The JetBrains folks are generally pretty quick about giving the ok to new plugin versions; I'd expect it be available either Monday or Tuesday.
It seems that Idea recently started to provide Spock method templates out of box (they are available in the plain installation of Idea 133.79) which causes following exception on startup after the Spock plugin is installed. Probably it would be enough to not provide file template in the plugin version for Idea 13.