https: prevent options object from being mutated

Previously, when passing options object to the agent.createConnection
method, the same options object got modified within the method. Now,
any modification will happen on only a copy of the object.

Fixes: #31119

PR-URL: #31151
Reviewed-By: Ruben Bridgewater <[email protected]>
Reviewed-By: James M Snell <[email protected]>
Reviewed-By: Anto Aravinth <[email protected]>
Reviewed-By: David Carlier <[email protected]>
Reviewed-By: Luigi Pinca <[email protected]>
Reviewed-By: Rich Trott <[email protected]>

lib/https.js

@@ -95,9 +95,11 @@ function createConnection(port, host, options) {
   if (port !== null && typeof port === 'object') {
     options = port;
   } else if (host !== null && typeof host === 'object') {
-    options = host;
+    options = { ...host };
   } else if (options === null || typeof options !== 'object') {
     options = {};
+  } else {
+    options = { ...options };
   }
 
   if (typeof port === 'number') {

test/parallel/test-https-agent-create-connection.js

@@ -132,3 +132,27 @@ function createServer() {
     }));
   }));
 }
+
+// `options` should not be modified
+{
+  const server = createServer();
+  server.listen(0, common.mustCall(() => {
+    const port = server.address().port;
+    const host = 'localhost';
+    const options = {
+      port: 3000,
+      rejectUnauthorized: false
+    };
+
+    const socket = agent.createConnection(port, host, options);
+    socket.on('connect', common.mustCall((data) => {
+      socket.end();
+    }));
+    socket.on('end', common.mustCall(() => {
+      assert.deepStrictEqual(options, {
+        port: 3000, rejectUnauthorized: false
+      });
+      server.close();
+    }));
+  }));
+}