fix ci

src/tbd/nrepl/core.clj

@@ -1,7 +1,8 @@
 (ns tbd.nrepl.core
   "The on-demand nREPL debug server. No HTTP here."
   (:require [clojure.string :as str]
-            [nrepl.server :as nrepl]))
+            [nrepl.server :as nrepl])
+  (:import (java.net InetAddress InetSocketAddress Socket)))
 
 (def default-port 7888)
 
@@ -35,11 +36,32 @@
         (reset! state {:server server :bind bind :port (:port server)})))
     (status)))
 
+(defn- accepting?
+  "True if something takes connections on `bind`:`port` (a wildcard bind is probed via loopback)."
+  [bind port]
+  (let [addr (InetAddress/getByName bind)
+        addr (if (.isAnyLocalAddress addr) (InetAddress/getLoopbackAddress) addr)]
+    (try (with-open [s (Socket.)]
+           (.connect s (InetSocketAddress. addr (int port)) 200)
+           true)
+         (catch java.io.IOException _ false))))
+
+(defn- await-closed
+  "Blocks until `bind`:`port` refuses connections, for up to two seconds. Closing a server socket
+  doesn't stop the kernel queueing connections while the accept loop is still blocked in accept(),
+  so for a moment after `stop-server` the port can still be connected to."
+  [bind port]
+  (let [deadline (+ (System/nanoTime) 2000000000)]
+    (while (and (accepting? bind port) (< (System/nanoTime) deadline))
+      (Thread/sleep 5))))
+
 (defn disable!
-  "Stops the server if it's running; returns the status."
+  "Stops the server if it's running, and returns once its port really refuses connections;
+  returns the status."
   []
   (locking state
-    (when-let [{:keys [server]} @state]
+    (when-let [{:keys [server bind port]} @state]
       (nrepl/stop-server server)
+      (await-closed bind port)
       (reset! state nil))
     (status)))