Improve class name generation for scripts and REPL snippets

- allow to override default name/scheme
- implement host/engine specific names for jsr223 to avoid classloading
  clashes (also fix "eval in eval" test)

libraries/scripting/common/src/kotlin/script/experimental/api/replData.kt

@@ -8,6 +8,7 @@ package kotlin.script.experimental.api
 import java.io.Serializable
 import kotlin.script.experimental.util.PropertiesCollection
 
+// Warning: during the transition to the new REPL infrastructure, should be kept in sync with REPL_CODE_LINE_FIRST_NO/REPL_CODE_LINE_FIRST_GEN
 const val REPL_SNIPPET_FIRST_NO = 1
 const val REPL_SNIPPET_FIRST_GEN = 1
 
@@ -48,3 +49,17 @@ val ScriptCompilationConfigurationKeys.repl
  */
 val ReplScriptCompilationConfigurationKeys.resultFieldPrefix by PropertiesCollection.key<String>("res")
 
+typealias MakeSnippetIdentifier = (ScriptCompilationConfiguration, ReplSnippetId) -> String
+
+/**
+ * The REPL snippet class identifier generation function
+ */
+val ReplScriptCompilationConfigurationKeys.makeSnippetIdentifier by PropertiesCollection.key<MakeSnippetIdentifier>(
+    { _, snippetId ->
+        makeDefaultSnippetIdentifier(snippetId)
+    })
+
+fun makeDefaultSnippetIdentifier(snippetId: ReplSnippetId) =
+    "Line_${snippetId.no}${if (snippetId.generation > REPL_SNIPPET_FIRST_GEN) "_gen_${snippetId.generation}" else ""}"
+
+

libraries/scripting/common/src/kotlin/script/experimental/api/scriptCompilation.kt

@@ -57,6 +57,11 @@ fun ScriptCompilationConfiguration?.with(body: ScriptCompilationConfiguration.Bu
  */
 val ScriptCompilationConfigurationKeys.displayName by PropertiesCollection.key<String>()
 
+/**
+ * The default script class name
+ */
+val ScriptCompilationConfigurationKeys.defaultIdentifier by PropertiesCollection.key<String>("Script")
+
 /**
  * The script filename extension
  * Used for the primary script definition selection as well as to assign a kotlin-specific file type to the files with the extension in Intellij IDEA

libraries/scripting/jvm-host/src/kotlin/script/experimental/jvmhost/jsr223/KotlinJsr223ScriptEngineImpl.kt

@@ -9,9 +9,7 @@ import org.jetbrains.kotlin.cli.common.repl.*
 import java.util.concurrent.locks.ReentrantReadWriteLock
 import javax.script.ScriptContext
 import javax.script.ScriptEngineFactory
-import kotlin.script.experimental.api.ScriptCompilationConfiguration
-import kotlin.script.experimental.api.ScriptEvaluationConfiguration
-import kotlin.script.experimental.api.hostConfiguration
+import kotlin.script.experimental.api.*
 import kotlin.script.experimental.host.ScriptingHostConfiguration
 import kotlin.script.experimental.host.withDefaultsFrom
 import kotlin.script.experimental.jvm.baseClassLoader
@@ -42,6 +40,18 @@ class KotlinJsr223ScriptEngineImpl(
     val compilationConfiguration by lazy {
         ScriptCompilationConfiguration(baseCompilationConfiguration) {
             hostConfiguration.update { it.withDefaultsFrom(jsr223HostConfiguration) }
+            repl {
+                // Snippet classes should be named uniquely, to avoid classloading clashes in the "eval in eval" scenario
+                // TODO: consider applying the logic for any REPL, alternatively - develop other naming scheme to avoid clashes
+                makeSnippetIdentifier { configuration, snippetId ->
+                    val scriptContext: ScriptContext? = configuration[ScriptCompilationConfiguration.jsr223.getScriptContext]?.invoke()
+                    val engineState = scriptContext?.let {
+                        it.getBindings(ScriptContext.ENGINE_SCOPE)?.get(KOTLIN_SCRIPT_STATE_BINDINGS_KEY)
+                    }
+                    if (engineState == null) makeDefaultSnippetIdentifier(snippetId)
+                    else "ScriptingHost${System.identityHashCode(engineState).toString(16)}_${makeDefaultSnippetIdentifier(snippetId)}"
+                }
+            }
         }
     }
 

libraries/scripting/jvm-host/src/kotlin/script/experimental/jvmhost/repl/legacyReplCompilation.kt

@@ -74,7 +74,10 @@ internal class SourceCodeFromReplCodeLine(
     compilationConfiguration: ScriptCompilationConfiguration
 ) : SourceCode {
     override val text: String get() = codeLine.code
-    override val name: String = "${makeScriptBaseName(codeLine)}.${compilationConfiguration[ScriptCompilationConfiguration.fileExtension]}"
+    override val name: String =
+        "${compilationConfiguration[ScriptCompilationConfiguration.repl.makeSnippetIdentifier]!!(
+            compilationConfiguration, ReplSnippetIdImpl(codeLine.no, codeLine.generation, 0)
+        )}.${compilationConfiguration[ScriptCompilationConfiguration.fileExtension]}"
     override val locationId: String? = null
 }