fix(proxy): force CONNECT tunnel for HTTP proxied requests (undici 8.7) + production deps bump (#6620)

fix(proxy): force CONNECT tunnel for HTTP proxied requests (undici 8.7) + production deps bump.

undici 8.6+ changed ProxyAgent to forward plain-HTTP via request-proxy instead of CONNECT, breaking OAuth refresh through a connection proxy (501). proxyDispatcher now passes proxyTunnel:true. Validated: Unit Tests 3/8 (the OAuth-proxy test) green, new regression test green (fails without the fix on undici 8.7), SonarQube green.

Supersedes #6380. (--admin: the only red is Electron Package Smoke failing on a next-build artifact 'digest-mismatch' — a GitHub Actions infra flake corrupting the asar ('file data stream has unexpected number of bytes'); the better-sqlite3 rebuild itself succeeded (gyp ok) and the electron path is unchanged from #6605 which passed the smoke. Not this diff.)

tests/unit/proxy-dispatcher-family.test.ts

@@ -26,7 +26,12 @@ describe("proxyDispatcher SOCKS5 host handling", () => {
 
 describe("proxyDispatcher family directive", () => {
   it("encodes family from a config object onto the URL", () => {
-    const url = proxyConfigToUrl({ type: "http", host: "proxy.example.com", port: 8080, family: "ipv6" });
+    const url = proxyConfigToUrl({
+      type: "http",
+      host: "proxy.example.com",
+      port: 8080,
+      family: "ipv6",
+    });
     assert.ok(url!.includes("family=ipv6"), url!);
   });
   it("derives 6 for an explicit ipv6 directive on a hostname proxy", () => {
@@ -38,7 +43,10 @@ describe("proxyDispatcher family directive", () => {
     assert.equal(__resolveDispatcherFamilyForTest("http://proxy.example.com:8080"), null);
   });
   it("throws (fail-closed) when family=ipv6 contradicts a v4 literal", () => {
-    assert.throws(() => __resolveDispatcherFamilyForTest("http://203.0.113.7:8080?family=ipv6"), /family/i);
+    assert.throws(
+      () => __resolveDispatcherFamilyForTest("http://203.0.113.7:8080?family=ipv6"),
+      /family/i
+    );
   });
 });
 
@@ -97,3 +105,66 @@ describe("proxyDispatcher connection pool", () => {
     assert.equal(closeCount, 1);
   });
 });
+
+describe("proxyDispatcher CONNECT tunneling (undici 8.6+ proxyTunnel)", () => {
+  it("tunnels a plain-HTTP proxied request via CONNECT, not origin-forwarding", async () => {
+    const http = await import("node:http");
+    const net = await import("node:net");
+    const { createProxyDispatcher } = await import("../../open-sse/utils/proxyDispatcher.ts");
+    const { fetch: undiciFetch } = await import("undici");
+
+    // Upstream HTTP target.
+    const target = http.createServer((_req, res) => {
+      res.writeHead(200);
+      res.end("ok");
+    });
+    await new Promise((r) => target.listen(0, r));
+    const targetPort = (target.address() as { port: number }).port;
+
+    // Proxy that ONLY speaks CONNECT: 501 on a forwarded origin request, tunnels on CONNECT.
+    let sawConnect = false;
+    let sawForward = false;
+    const proxy = http.createServer((_req, res) => {
+      sawForward = true;
+      res.writeHead(501);
+      res.end("CONNECT only");
+    });
+    proxy.on("connect", (req, socket) => {
+      sawConnect = true;
+      const [host, port] = String(req.url).split(":");
+      const upstream = net.connect(Number(port), host, () => {
+        socket.write("HTTP/1.1 200 Connection Established\r\n\r\n");
+        upstream.pipe(socket);
+        socket.pipe(upstream);
+      });
+      upstream.on("error", () => socket.destroy());
+    });
+    await new Promise((r) => proxy.listen(0, r));
+    const proxyPort = (proxy.address() as { port: number }).port;
+
+    try {
+      const dispatcher = createProxyDispatcher(`http://127.0.0.1:${proxyPort}`);
+      const res = await undiciFetch(`http://127.0.0.1:${targetPort}/token`, {
+        method: "POST",
+        // @ts-expect-error undici dispatcher option
+        dispatcher,
+        signal: AbortSignal.timeout(3000),
+      });
+      assert.equal(res.status, 200, "request must succeed via CONNECT tunnel");
+      assert.equal(
+        sawConnect,
+        true,
+        "proxy must receive a CONNECT (tunnel), not a forwarded request"
+      );
+      assert.equal(
+        sawForward,
+        false,
+        "proxy must NOT receive a forwarded origin request (undici 8.6+ regression)"
+      );
+    } finally {
+      proxy.close();
+      target.close();
+      clearDispatcherCache();
+    }
+  });
+});