PactV3 mock server fails to handle DELETE requests after upgrade to v16.3.0 (pact-core v19)

[lsigism]

Description

After upgrading from @pact-foundation/pact v16.2.0 to v16.3.0, consumer Pact tests using DELETE HTTP method fail with TypeError: Network request failed. Tests using GET and POST methods continue to work as expected.

Versions

• @pact-foundation/pact: 16.3.0 (works on 16.2.0)
• @pact-foundation/pact-core: 19.1.0 (via 16.3.0) vs 18.1.0 (via 16.2.0)
• Node.js: 22.x
• Test runner: Jest + jsdom + whatwg-fetch
• OS: Ubuntu (GitHub Actions runner)

Steps to reproduce

1. Create a PactV3 consumer test with a DELETE interaction:

import { PactV3 } from "@pact-foundation/pact";

const provider = new PactV3({
  consumer: "my-consumer",
  provider: "my-provider",
  dir: path.resolve(process.cwd(), "pacts"),
});

describe("DELETE resource", () => {
  it("deletes the resource", async () => {
    provider
      .given("resource exists")
      .uponReceiving("a DELETE request")
      .withRequest({
        method: "DELETE",
        path: "/api/resource/1",
        headers: {
          Accept: "application/json",
        },
      })
      .willRespondWith({
        status: 200,
        headers: { "Content-Type": "application/json" },
        body: '{}',
      });

    return provider.executeTest(async (mockServer) => {
      const response = await fetch(`${mockServer.url}/api/resource/1`, {
        method: "DELETE",
        headers: {
          Accept: "application/json",
        },
      });

      expect(response.status).toEqual(200);
    });
  });
});

2. Run the test with @pact-foundation/pact v16.3.0

Expected behaviour

The mock server handles the DELETE request and returns the configured response (as it does in v16.2.0).

Actual behaviour

The test fails with:

TypeError: Network request failed

  at node_modules/whatwg-fetch/dist/fetch.umd.js:567:18
  at Timeout.task [as _onTimeout] (node_modules/jsdom/lib/jsdom/browser/Window.js:579:19)

The fetch call cannot connect to the Pact mock server for DELETE requests. GET and POST interactions against the same mock server work fine.

Suspected root cause

v16.3.0 bumped @pact-foundation/pact-core from ^18.1.0 to ^19.1.0. The breaking change in pact-core v19.0.0 (release notes) replaced the deprecated pactffiCreateMockServerForPact with pactffiCreateMockServerForTransport:

- const port = ffi.pactffiCreateMockServerForPact(pactPtr, `${address}:${requestedPort || 0}`, tls);
+ const port = ffi.pactffiCreateMockServerForTransport(pactPtr, address, requestedPort || 0, tls ? 'https' : 'http', '');

This new mock server transport implementation appears to not handle DELETE requests correctly — or there's a timing/connection issue specific to DELETE when using whatwg-fetch in a jsdom environment.

Workaround

Pin @pact-foundation/pact to 16.2.0.

[mefellows]

Thanks for the great report. That's strange indeed. We would need to determine if the bug is in this module (seems unlikely), pact-core (possibly the invocation of the FFI method is incorrect or another detail is missing - seems unlikely if other methods work) or (more likely) the upstream library.

[mefellows]

OK I just managed to get that test repro working locally using both jest and mocha (to rule out jest behaviour). It's not using whatwg-fetch or jsdom (i.e. native fetch), so that might be a clue.

If you can, set log level to debug (or perhaps trace) to see if you can inspect what the network calls are doing - perhaps it's initiating a network call and getting stuck or something.

[mefellows]

OK this is more promising:

  console.log
    [23:13:08.024] INFO (55037): 0.5.3: pact native library successfully found, and the correct version

      at Object.write (node_modules/@pact-foundation/pact-core/src/logger/pino.ts:17:17)
          at Array.every (<anonymous>)


  console.error
    Error: Error: Response for preflight has invalid HTTP status code 500
        at Object.dispatchError (/private/tmp/repro/node_modules/jsdom/lib/jsdom/living/xhr/xhr-utils.js:62:19)
        at EventEmitter.<anonymous> (/private/tmp/repro/node_modules/jsdom/lib/jsdom/living/xhr/XMLHttpRequest-impl.js:655:18)
        at EventEmitter.emit (node:events:530:35)
        at Request.<anonymous> (/private/tmp/repro/node_modules/jsdom/lib/jsdom/living/xhr/xhr-utils.js:349:16)
        at Request.emit (node:events:518:28)
        at Request._processResponse (/private/tmp/repro/node_modules/jsdom/lib/jsdom/living/helpers/http-request.js:240:12)
        at ClientRequest.<anonymous> (/private/tmp/repro/node_modules/jsdom/lib/jsdom/living/helpers/http-request.js:107:12)
        at Object.onceWrapper (node:events:633:26)
        at ClientRequest.emit (node:events:518:28)
        at HTTPParser.parserOnIncomingClient [as onIncoming] (node:_http_client:716:27)
        at HTTPParser.parserOnHeadersComplete (node:_http_common:117:17)
        at Socket.socketOnData (node:_http_client:558:22)
        at Socket.emit (node:events:518:28)
        at addChunk (node:internal/streams/readable:561:12)
        at readableAddChunkPushByteMode (node:internal/streams/readable:512:3)
        at Socket.Readable.push (node:internal/streams/readable:392:5)
        at TCP.onStreamRead (node:internal/stream_base_commons:189:23)
        at TCP.callbackTrampoline (node:internal/async_hooks:130:17) {
      type: 'XMLHttpRequest'
    }

      at VirtualConsole.<anonymous> (node_modules/@jest/environment-jsdom-abstract/build/index.js:87:23)
      at Object.dispatchError (node_modules/jsdom/lib/jsdom/living/xhr/xhr-utils.js:65:53)
      at EventEmitter.<anonymous> (node_modules/jsdom/lib/jsdom/living/xhr/XMLHttpRequest-impl.js:655:18)
      at Request.<anonymous> (node_modules/jsdom/lib/jsdom/living/xhr/xhr-utils.js:349:16)
      at Request._processResponse (node_modules/jsdom/lib/jsdom/living/helpers/http-request.js:240:12)
      at ClientRequest.<anonymous> (node_modules/jsdom/lib/jsdom/living/helpers/http-request.js:107:12)

  console.log
    [23:13:08.164] ERROR (55037): pact@16.3.0: Test failed for the following reasons:

      Mock server failed with the following mismatches:

    	0) The following request was expected but not received:
    	    Method: DELETE
    	    Path: /api/resource/1
    	    Headers:
    	      Accept: application/json

      at Object.write (node_modules/@pact-foundation/pact-core/src/logger/pino.ts:17:17)

 FAIL  ./pact.test.js
  DELETE resource
    ✕ deletes the resource (87 ms)

  ● DELETE resource › deletes the resource

    TypeError: Network request failed

      at node_modules/whatwg-fetch/dist/fetch.umd.js:567:18
      at Timeout.task [as _onTimeout] (node_modules/jsdom/lib/jsdom/browser/Window.js:579:19)

Test Suites: 1 failed, 1 total
Tests:       1 failed, 1 total
Snapshots:   0 total
Time:        1.379 s
Ran all test suites matching pact.test.js.
➜  repro

That suggests it's CORS that's the issue. I tried with GET and POST which (as you state) work just fine. When inspecting the logs (debug level) I see the following OPTIONS request:

       method: OPTIONS
       path: /api/resource/1
       query: None
       headers: Some({"referer": ["http://localhost/"], "user-agent": ["Mozilla/5.0 (darwin) AppleWebKit/537.36 (KHTML, like Gecko) jsdom/26.1.0"], "host": ["127.0.0.1:65508"], "connection": ["keep-alive"], "origin": ["http://localhost"], "access-control-request-method": ["DELETE"]})
       body: Empty

This is only present for DELETE, and not for others - which doesn't appear to be correct.

Current Theory

I suspect the newer form of mock server doesn't support CORS out-of-the-box. It was originally added back in 2020: https://github.com/pact-foundation/pact-reference/blob/ac7df19d8d30f609c43fde2d5a38b708bcdd758f/rust/pact_matching/CHANGELOG.md?plain=1#L908

[mefellows]

Progress.

The cors_preflight property was previously a default of the deprecated server, and removed from the new in pact-foundation/pact-reference#502.

Manually patching node_modules/@pact-foundation/pact-core/src/consumer/index.js fixes the issue. with the following fixes it (by passing a transport config in):

const port = ffi.pactffiCreateMockServerForTransport(pactPtr, address, requestedPort || 0, tls ? 'https' : 'http', JSON.stringify({"corsPreflight": true}));

Solutions

1. Add that a default to the pact core
2. Update the newer FFI fn to have the previous default behaviour
3. Support injecting the transport details from the consumer (Pact JS) into the core

Option 2 probably makes sense, as does allowing a user to configure it.

cc @JP-Ellis @rholshausen

[jonathan-boudreau-work]

I'm getting this for PATCH also.