Improve hashing of script files

libraries/tools/kotlin-main-kts/src/org/jetbrains/kotlin/mainKts/scriptDef.kt

@@ -8,6 +8,7 @@ package org.jetbrains.kotlin.mainKts
 import kotlinx.coroutines.runBlocking
 import org.jetbrains.kotlin.mainKts.impl.IvyResolver
 import java.io.File
+import java.nio.ByteBuffer
 import java.security.MessageDigest
 import kotlin.script.dependencies.ScriptContents
 import kotlin.script.dependencies.ScriptDependenciesResolver
@@ -36,6 +37,7 @@ abstract class MainKtsScript(val args: Array<String>)
 
 const val COMPILED_SCRIPTS_CACHE_DIR_ENV_VAR = "KOTLIN_MAIN_KTS_COMPILED_SCRIPTS_CACHE_DIR"
 const val COMPILED_SCRIPTS_CACHE_DIR_PROPERTY = "kotlin.main.kts.compiled.scripts.cache.dir"
+const val COMPILED_SCRIPTS_CACHE_VERSION = 1
 
 class MainKtsScriptDefinition : ScriptCompilationConfiguration(
     {
@@ -149,15 +151,25 @@ class MainKtsConfigurator : RefineScriptCompilationConfigurationHandler {
 }
 
 private fun compiledScriptUniqueName(script: SourceCode, scriptCompilationConfiguration: ScriptCompilationConfiguration): String {
-    val digestWrapper = MessageDigest.getInstance("MD5")
+    val digestWrapper = MessageDigest.getInstance("SHA-256")
-    digestWrapper.update(script.text.toByteArray())
+
+    fun addToDigest(chunk: String) = with(digestWrapper) {
+        val chunkBytes = chunk.toByteArray()
+        update(chunkBytes.size.toByteArray())
+        update(chunkBytes)
+    }
+
+    digestWrapper.update(COMPILED_SCRIPTS_CACHE_VERSION.toByteArray())
+    addToDigest(script.text)
     scriptCompilationConfiguration.notTransientData.entries
         .sortedBy { it.key.name }
         .forEach {
-            digestWrapper.update(it.key.name.toByteArray())
+            addToDigest(it.key.name)
-            digestWrapper.update(it.value.toString().toByteArray())
+            addToDigest(it.value.toString())
         }
     return digestWrapper.digest().toHexString()
 }
 
 private fun ByteArray.toHexString(): String = joinToString("", transform = { "%02x".format(it) })
+
+private fun Int.toByteArray() = ByteBuffer.allocate(Int.SIZE_BYTES).also { it.putInt(this) }.array()