Don't kill process when embedded

Author: fmagin

src/main/kotlin/org/jetbrains/kotlinx/jupyter/protocol.kt

@@ -195,7 +195,15 @@ fun JupyterConnection.Socket.controlMessagesHandler(msg: Message, repl: ReplForJ
         is ShutdownRequest -> {
             repl?.evalOnShutdown()
             send(makeReplyMessage(msg, MessageType.SHUTDOWN_REPLY, content = msg.content))
-            exitProcess(0)
+            // exitProcess would kill the entire process that embedded the kernel
+            // Instead the controlThread will be interrupted,
+            // which will then interrupt the mainThread and make kernelServer return
+            if ((repl as? ReplForJupyterImpl)?.isEmbedded() == true) {
+                log.info("Interrupting controlThread to trigger kernel shutdown")
+                throw InterruptedException()
+            } else {
+                exitProcess(0)
+            }
         }
     }
 }

src/main/kotlin/org/jetbrains/kotlinx/jupyter/repl.kt

@@ -148,6 +148,8 @@ class ReplForJupyterImpl(
     private val embedded: Boolean = false,
 ) : ReplForJupyter, ReplOptions, BaseKernelHost, KotlinKernelHostProvider {
 
+    fun isEmbedded() = embedded
+
     constructor(
         config: KernelConfig,
         runtimeProperties: ReplRuntimeProperties,