[version] Annotate properties used by version generator as inputs

shared/buildSrc/src/main/kotlin/org/jetbrains/kotlin/VersionGenerator.kt

@@ -3,8 +3,7 @@ package org.jetbrains.kotlin
 import groovy.lang.Closure
 import org.gradle.api.DefaultTask
 import org.gradle.api.Task
-import org.gradle.api.tasks.OutputDirectory
-import org.gradle.api.tasks.OutputFile
+import org.gradle.api.tasks.*
 import java.io.File
 
 
@@ -14,22 +13,31 @@ open class VersionGenerator: DefaultTask() {
     @OutputFile
     val versionFile:File = project.file("${versionSourceDirectory.path}/org/jetbrains/kotlin/konan/KonanVersion.kt")
 
+    val konanVersion: String
+        @Input get() = project.properties["konanVersion"].toString()
+
+    val buildNumber: String?
+        @Optional @Input get() = System.getenv("BUILD_NUMBER")
+
+    val meta: String
+        @Input get() = project.properties["konanMetaVersion"]?.let {
+            "MetaVersion.${it.toString().toUpperCase()}"
+        } ?: "MetaVersion.DEV"
+
 
     override fun configure(closure: Closure<*>): Task {
         val result = super.configure(closure)
         doFirst {
             val content = buildString {
                 operator fun String.unaryPlus() = this@buildString.append(this)
-                val version = project.properties["konanVersion"].toString().split(".")
+                val version = konanVersion.split(".")
                 val major = version[0].toInt()
                 val minor = version[1].toInt()
                 val maintenance = if (version.size > 2) version[2].toInt() else 0
-                val buildCounter = System.getenv("BUILD_NUMBER")
-                project.logger.info("BUILD_NUMBER: $buildCounter")
-                val build = buildCounter?.let {
+                project.logger.info("BUILD_NUMBER: $buildNumber")
+                val build = buildNumber?.let {
                     it.split("-")[2].toInt() //7-dev-buildcount
                 }?: -1
-                val meta = project.properties["konanMetaVersion"]?.let { "MetaVersion.${it.toString().toUpperCase()}" } ?: "MetaVersion.DEV"
 
                 + """
                      |package org.jetbrains.kotlin.konan