http2: client session destroy also destroys associated socket

lib/internal/http2/core.js

@@ -435,7 +435,16 @@ class Http2Session extends EventEmitter {
   destroy() {
     const state = this[kState];
     const streams = state.streams;
+    const socket = this[kSocket];
+    if (state.destroyed) {
+      return;
+    }
     state.destroyed = true;
+    if (!socket.destroyed) {
+      socket.destroy();
+    }
+    this[kSocket] = undefined;
+    this[kServer] = undefined;
     timers.unenroll(this);
     streams.forEach((value, key) => {
       value[kSession] = undefined;
@@ -955,12 +964,10 @@ Object.defineProperties(Http2Session.prototype, {
 // establishment of a new connection.
 function socketDestroy(error) {
   const session = this[kSession];
-  session.destroy();
-  session[kServer] = undefined;
-  session[kSocket] = undefined;
   this[kServer] = undefined;
   this.destroy = this[kDestroySocket];
   this.destroy(error);
+  session.destroy();
 }
 
 function socketOnResume() {

test/parallel/test-http2-client-destroy.js

@@ -0,0 +1,48 @@
+'use strict';
+
+const common = require('../common');
+const assert = require('assert');
+const h2 = require('http2');
+
+const server = h2.createServer();
+server.listen(0);
+
+server.on('listening', common.mustCall(function() {
+  const port = this.address().port;
+  const headers = { ':path': '/' };
+
+  const destroyCallbacks = [
+    client => client.destroy(),
+    client => client.socket.destroy()
+  ]
+
+  let remaining = destroyCallbacks.length;
+
+  destroyCallbacks.forEach((destroyCallback) => {
+    const client = h2.connect(`http://localhost:${port}`);
+    client.on('connect', common.mustCall(() => {
+      const socket = client.socket;
+
+      assert(client.socket, 'client session has associated socket');
+      assert(!client.destroyed,
+        'client has not been destroyed before destroy is called');
+      assert(!socket.destroyed,
+        'socket has not been destroyed before destroy is called');
+
+      // Ensure that 'close' event is emitted
+      client.on('close', common.mustCall(() => {}));
+
+      destroyCallback(client);
+
+      assert(!client.socket, 'client.socket undefined after destroy is called');
+      assert(client.destroyed,
+        'client marked as destroyed after destroy is called');
+      assert(socket.destroyed,
+        'socket marked as destroyed after destroy is called');
+
+      if (--remaining === 0) {
+        server.close();
+      }
+    }));
+  });
+}));

test/parallel/test-http2-create-client-connect.js

@@ -28,7 +28,7 @@ const URL = url.URL;
     let count = items.length;
 
     const maybeClose = common.mustCall((client) => {
-      client.socket.destroy();
+      client.destroy();
       if (--count === 0) {
         setImmediate(() => server.close());
       }

test/parallel/test-http2-create-client-session.js

@@ -47,7 +47,7 @@ server.on('listening', common.mustCall(function() {
       assert.strictEqual(body, data);
       if (--expected === 0) {
         server.close();
-        client.socket.destroy();
+        client.destroy();
       }
     }));
     req.end();