diff --git a/convention/src/main/kotlin/io/gitlab/jfronny/scripts/JGitExt.kt b/convention/src/main/kotlin/io/gitlab/jfronny/scripts/JGitExt.kt
index 7b74efd..30d361d 100644
--- a/convention/src/main/kotlin/io/gitlab/jfronny/scripts/JGitExt.kt
+++ b/convention/src/main/kotlin/io/gitlab/jfronny/scripts/JGitExt.kt
@@ -18,7 +18,7 @@ fun initializeGit() {
     SystemReader.setInstance(object : SystemReader() {
         override fun getHostname(): String = original.hostname
         override fun getenv(key: String): String? = if (key == "PATH") null else original.getenv(key)
-        override fun getProperty(key: String?): String = original.getProperty(key)
+        override fun getProperty(key: String?): String? = original.getProperty(key)
         override fun openUserConfig(parent: Config?, fs: FS?): FileBasedConfig = original.openUserConfig(parent, fs)
         override fun openSystemConfig(parent: Config?, fs: FS?): FileBasedConfig = original.openSystemConfig(parent, fs)
         override fun openJGitConfig(parent: Config?, fs: FS?): FileBasedConfig = original.openJGitConfig(parent, fs)