Use optionals instead of lateinit

Author: f-meloni

danger-kotlin-library/src/main/kotlin/systems/danger/kotlin/MainDangerRunner.kt

@@ -19,7 +19,6 @@ import java.util.concurrent.atomic.AtomicReference
  * @param jsonOutputPath the output json file path used to publish the danger results on your Pull Request
  */
 internal class MainDangerRunner(jsonInputFilePath: FilePath, jsonOutputPath: FilePath) : DangerContext {
-
     private val jsonOutputFile: File = File(jsonOutputPath)
 
     val danger: DangerDSL = JsonParser.decodeJson<DSL>(jsonInputFilePath).danger
@@ -86,7 +85,7 @@ internal class MainDangerRunner(jsonInputFilePath: FilePath, jsonOutputPath: Fil
     }
 
     override fun suggest(code: String, file: FilePath, line: Int) {
-        if (dangerRunner.danger.onGitHub) {
+        if (runnerInstance.danger.onGitHub) {
             val message = "```suggestion\n $code \n```"
             markdown(Violation(message, file, line))
         } else {

danger-kotlin-library/src/main/kotlin/systems/danger/kotlin/MainScript.kt

@@ -3,7 +3,16 @@ package systems.danger.kotlin
 import systems.danger.kotlin.models.danger.DangerDSL
 import systems.danger.kotlin.models.git.FilePath
 
-internal lateinit var dangerRunner: MainDangerRunner
+internal var dangerRunner: MainDangerRunner? = null
+
+internal val runnerInstance: MainDangerRunner
+    get() {
+        if(dangerRunner != null) {
+            return dangerRunner!!
+        } else {
+            throw IllegalArgumentException("Danger must be initialised before accessing it")
+        }
+    }
 
 /**
  * Syntactic sugar that allows you to work with a [DangerDSL] descriptor in a single Danger block.
@@ -40,7 +49,7 @@ fun Danger(args: Array<String>): DangerDSL {
         dangerRunner = MainDangerRunner(jsonInputFilePath, jsonOutputPath)
     }
 
-    return dangerRunner.danger
+    return dangerRunner!!.danger
 }
 
 /**
@@ -49,7 +58,7 @@ fun Danger(args: Array<String>): DangerDSL {
  * @param message the standard message
  */
 fun message(message: String) =
-    dangerRunner.message(message)
+    runnerInstance.message(message)
 
 /**
  * Adds an inline message message to the Danger report
@@ -59,15 +68,15 @@ fun message(message: String) =
  * @param line the line number into the target file
  */
 fun message(message: String, file: FilePath, line: Int) =
-    dangerRunner.message(message, file, line)
+    runnerInstance.message(message, file, line)
 
 /**
  * Adds an inline markdown message to the Danger report
  *
  * @param message the markdown formatted message
  */
 fun markdown(message: String) =
-    dangerRunner.markdown(message)
+    runnerInstance.markdown(message)
 
 /**
  * Adds an inline markdown message to the Danger report
@@ -77,15 +86,15 @@ fun markdown(message: String) =
  * @param line the line number into the target file
  */
 fun markdown(message: String, file: FilePath, line: Int) =
-    dangerRunner.markdown(message, file, line)
+    runnerInstance.markdown(message, file, line)
 
 /**
  * Adds an inline warning message to the Danger report
  *
  * @param message the warning message
  */
 fun warn(message: String) =
-    dangerRunner.warn(message)
+    runnerInstance.warn(message)
 
 /**
  * Adds an inline warning message to the Danger report
@@ -95,15 +104,15 @@ fun warn(message: String) =
  * @param line the line number into the target file
  */
 fun warn(message: String, file: FilePath, line: Int) =
-    dangerRunner.warn(message, file, line)
+    runnerInstance.warn(message, file, line)
 
 /**
  * Adds an inline fail message to the Danger report
  *
  * @param message the fail message
  */
 fun fail(message: String) =
-    dangerRunner.fail(message)
+    runnerInstance.fail(message)
 
 /**
  * Adds an inline fail message to the Danger report
@@ -113,7 +122,7 @@ fun fail(message: String) =
  * @param line the line number into the target file
  */
 fun fail(message: String, file: FilePath, line: Int) =
-    dangerRunner.fail(message, file, line)
+    runnerInstance.fail(message, file, line)
 
 /**
  * Adds an inline suggested code message to the Danger report
@@ -123,4 +132,4 @@ fun fail(message: String, file: FilePath, line: Int) =
  * @param line the line number into the target file
  */
 fun suggest(code: String, file: FilePath, line: Int) =
-    dangerRunner.suggest(code, file, line)
+    runnerInstance.suggest(code, file, line)