From 7e13eada31c6e7e0cc3e4470028da608e2c1771b Mon Sep 17 00:00:00 2001
From: Radon Rosborough <radon.neon@gmail.com>
Date: Mon, 30 Aug 2021 21:35:13 -0700
Subject: [PATCH] Report better errors for non-repl languages

---
 backend/api.js  |  4 ++++
 cli/src/main.go | 19 +++++++++++++++++++
 2 files changed, 23 insertions(+)

diff --git a/backend/api.js b/backend/api.js
index 70c8f73..433bc8d 100644
--- a/backend/api.js
+++ b/backend/api.js
@@ -58,6 +58,10 @@ export class Session {
     try {
       setTimeout(this.teardown, 3600 * 1000); // max session length of 1hr
       allSessions.add(this);
+      this.send({
+        event: "langConfig",
+        config: this.config,
+      });
       const containerArgs = this.privilegedSession();
       const containerProc = spawn(containerArgs[0], containerArgs.slice(1));
       this.container = {
diff --git a/cli/src/main.go b/cli/src/main.go
index f79ce45..d15ac46 100644
--- a/cli/src/main.go
+++ b/cli/src/main.go
@@ -31,6 +31,15 @@ type message struct {
 	Event string `json:"event"`
 }
 
+type langConfig struct {
+	message
+	Config struct {
+		Id   string `json:"id"`
+		Name string `json:"name"`
+		Repl string `json:"repl"`
+	} `json:"config"`
+}
+
 type errorMessage struct {
 	message
 	Error string `json:"errorMessage"`
@@ -121,6 +130,16 @@ func run() error {
 					return
 				}
 				done1 <- errors.New(msg.Error)
+			case "langConfig":
+				var msg langConfig
+				if err := json.Unmarshal(rawMsg, &msg); err != nil {
+					done1 <- errors.Wrap(err, "failed to parse websocket message")
+					return
+				}
+				if msg.Config.Repl == "" {
+					done1 <- fmt.Errorf("%s has no repl, you must provide a file to run", msg.Config.Name)
+					return
+				}
 			case "terminalOutput":
 				var msg terminalOutput
 				if err := json.Unmarshal(rawMsg, &msg); err != nil {