taler-typescript-core

commit e430a6f837ccf424a5a2b822811c67f5613904cf
parent 41c5d3e781ccf1151a130a94a34a3252641a86bf
Author: Christian Grothoff <christian@grothoff.org>
Date:   Sat, 31 Oct 2026 11:14:12 +0100

never reserve the same TCP port twice

Diffstat:
M
packages/taler-harness/src/integrationtests/wallet-web-ui-test-support.ts
 | 
51
+++++++++++++++++++++++++++++++++++++++------------

1 file changed, 39 insertions(+), 12 deletions(-)
diff --git a/packages/taler-harness/src/integrationtests/wallet-web-ui-test-support.ts b/packages/taler-harness/src/integrationtests/wallet-web-ui-test-support.ts
@@ -73,20 +73,47 @@ export function walletWebUiArtifactPath(
   return path.join(walletWebUiDirectory, "dist/harness", variant, ...entries);
 }
 
+/**
+ * Ports already handed out by this worker.  A reservation only binds port 0 and
+ * closes the socket again, so without this the kernel is free to return the
+ * same ephemeral port to the very next call.  A test that reserves two ports
+ * before starting anything then runs both of its services on one port: the
+ * second one dies with EADDRINUSE while its URL still answers, which looks like
+ * a product bug instead of a port clash.
+ */
+const reservedTcpPorts = new Set<number>();
+
 export async function reserveTcpPort(): Promise<number> {
-  const server = net.createServer();
-  await new Promise<void>((resolve, reject) => {
-    server.once("error", reject);
-    server.listen(0, "127.0.0.1", resolve);
-  });
-  const address = server.address();
-  if (!address || typeof address === "string") {
-    throw Error("could not reserve a TCP port");
+  // Candidates that turned out to be already reserved stay bound until we have
+  // a fresh one, so that the kernel has to pick a different port for the next
+  // attempt.
+  const heldServers: net.Server[] = [];
+  try {
+    for (let attempt = 0; attempt < 64; attempt++) {
+      const server = net.createServer();
+      await new Promise<void>((resolve, reject) => {
+        server.once("error", reject);
+        server.listen(0, "127.0.0.1", resolve);
+      });
+      heldServers.push(server);
+      const address = server.address();
+      if (!address || typeof address === "string") {
+        throw Error("could not reserve a TCP port");
+      }
+      if (reservedTcpPorts.has(address.port)) {
+        continue;
+      }
+      reservedTcpPorts.add(address.port);
+      return address.port;
+    }
+    throw Error("could not reserve an unused TCP port");
+  } finally {
+    for (const server of heldServers) {
+      await new Promise<void>((resolve, reject) =>
+        server.close((error) => (error ? reject(error) : resolve())),
+      );
+    }
   }
-  await new Promise<void>((resolve, reject) =>
-    server.close((error) => (error ? reject(error) : resolve())),
-  );
-  return address.port;
 }
 
 export async function waitForPwa(