node: inspector/CDP + bun inspect v26 compat (+70 tests)

src/js/internal/debugger.ts

@@ -146,14 +146,15 @@ export default function (
     return;
   }
 
-  if (isNodeInspector) {
-    // inspector.open(): CDP connections, URL reported back, control callback for close/forward.
-    // https://github.com/nodejs/node/blob/main/lib/inspector.js
-    let debug: Debugger | undefined;
+  // Control channel from the inspected thread to a node:inspector-owned
+  // server: close() stops it, open() restarts it here, and an in-process
+  // Session forwards Debugger.* to the shared backend. `initial` may be nil.
+  function createNodeInspectorControl(initial: Debugger | undefined) {
+    let debug = initial;
     let sessionBackend: Backend | undefined;
     let sessionAdapter: any;
     let sessionRefs = 0;
-    const control = (message: string) => {
+    function control(message: string) {
       let parsed: any;
       try {
         parsed = JSON.parse(message);
@@ -246,8 +247,15 @@ export default function (
           return;
         }
       }
-    };
+    }
+    return control;
+  }
 
+  if (isNodeInspector) {
+    // node:inspector's inspector.open(): serve CDP, report the URL back (for
+    // Node's "Debugger listening on ..." line), and hand back a control
+    // callback so the inspected thread can close the server / forward commands.
+    let debug: Debugger | undefined;
     try {
       debug = new Debugger(
         executionContextId,
@@ -264,11 +272,15 @@ export default function (
       // Register the control callback even though the server failed to start
       // (e.g. the port is in use), so a later inspector.open() can retry with
       // an "open" control message on this already-running debugger thread.
-      reportNodeInspectorServerStarted("", control, nodeInspectorListenErrorDetail(error));
+      reportNodeInspectorServerStarted(
+        "",
+        createNodeInspectorControl(undefined),
+        nodeInspectorListenErrorDetail(error),
+      );
       return;
     }
 
-    reportNodeInspectorServerStarted(debug.url!.href, control, undefined);
+    reportNodeInspectorServerStarted(debug.url!.href, createNodeInspectorControl(debug), undefined);
     return;
   }
 
@@ -289,8 +301,11 @@ export default function (
     exit("Failed to start inspector:\n", error);
   }
 
-  // If the user types --inspect, we print the URL to the console.
-  // If the user is using an editor extension, don't print anything.
+  const { cdpUrl } = debug;
+
+  // Print the URL for --inspect (not for editor extensions), *before*
+  // reportNodeInspectorServerStarted releases the inspected thread: Node's
+  // banner precedes script output and stderr-scraping tools rely on that order.
   if (!isAutomatic) {
     const debugUrl = debug.url;
     if (debugUrl) {
@@ -319,6 +334,13 @@ export default function (
     }
   }
 
+  // Report --inspect's CDP endpoint so node:inspector's url()/open()/close()
+  // behave as Node does for a CLI-started inspector; this also releases the
+  // inspected thread, which blocks on the report.
+  if (enableNodeCDP && cdpUrl) {
+    reportNodeInspectorServerStarted(cdpUrl, createNodeInspectorControl(debug), undefined);
+  }
+
   const notifyUrl = process.env["BUN_INSPECT_NOTIFY"] || "";
   if (notifyUrl) {
     // Only send this once.