pytest: `fundchannel` fails because "Script failed an OP_EQUALVERIFY operation"

[enaples]

Steps to reproduce

System: MacOS Tahoe 26.2

Bitcoin version tested: v28.1, v30.2
CLN: v25.12.1

Run tests/test_opening.py file:

EXPERIMENTAL_DUAL_FUND=0 uv run python -m pytest -vvvv tests/test_opening.py

Expected results

All v1 tests fail because:

pyln.client.lightning.RpcError: RPC call failed: method: fundchannel,
payload: 
{
    'id': '<id>', 
    'amount': <amount>, 
    'announce': True
}, 

error: 
{
    'code': -1, 
    'message': 'Error broadcasting transaction: error code: -26
                \\nerror message:\\n
                mempool-script-verify-flag-failed 
                (Script failed an OP_EQUALVERIFY operation), input 0 of <txid>
                (wtxid <wtxid>), spending <prev_txid>:<vout>. 
                Unsent tx discarded <raw_tx_hex>'
}

or

pyln.client.lightning.RpcError: RPC call failed: method: fundchannel, 
payload: 
{
    'id': '<id>', 
    'amount': <amount>, 
    'announce': True
}, 

error: 
{
    'code': 303, 
    'message': 'Error broadcasting funding tx: error code: -26
                \\\\nerror message:\\\\nmandatory-script-verify-flag-failed
                (Script failed an OP_EQUALVERIFY operation). Unsent tx 
                discarded <raw_tx_hex>.', 
    'data': {
                    'id': '<id>', 
                    'method': 'openchannel_signed'
                }
}

[daywalker90]

I tihnk there is something wrong with CLN under macOS. I tried adding tests for macOS for my plugins but they fail very often (not always). And i often saw fundchannel timing out like this:

FAILED test_summars.py::test_indexing - pyln.client.lightning.RpcError: RPC call failed: method: 
fundchannel,
payload: {'id': '022d223620a359a47ff7f7ac447c85c46c923da53389221a0054c11c1e3ca31d59@localhost:49446', 
          'amount': 1000000,
          'announce': True,
          'push_msat': 500000000, 
          'mindepth': 1
}, 
error: {'code': -1,
        'message': 'Owning subdaemon openingd died (62208)', 
        'data': {'id': '022d223620a359a47ff7f7ac447c85c46c923da53389221a0054c11c1e3ca31d59', 'method': 'fundchannel_start'}
}

Here are logs of a failed run:
https://github.com/daywalker90/summars/actions/runs/21533762279/job/62055119641

These kind of errors never happen on the ubuntu worker.

I reduced the parallel jobs from pytest -n 10 to pytest -n5 and i think the macOS worker errored less.

[enaples]

Never happened to me while I was testing v25.12 on macOS.

I figured out that using uv env from the master branch, commit #8637 and it is still happening on master.
While everything works perfectly (at least) till #8193. Just tested that the error does not occurr with v25.12 and v25.12.1 sitting on master at that commit.

self = <pyln.testing.utils.PrettyPrintingLightningRpc object at 0x10dc43460>, method = 'fundchannel'
payload = {'amount': 1000000, 'announce': True, 'id': '033845802d25b4e074ccfd7cd8b339a41dc75bf9978a034800444b51d42b07799a'}, cmdprefix = None, filter = None

    def call(self, method, payload=None, cmdprefix=None, filter=None):
        """Generic call API: you can set cmdprefix here, or set self.cmdprefix
        before the call is made.
    
        """
        self.logger.debug("Calling %s with payload %r", method, payload)
    
        if payload is None:
            payload = {}
        # Filter out arguments that are None
        if isinstance(payload, dict):
            payload = {k: v for k, v in payload.items() if v is not None}
    
        this_id = self.get_json_id(method, cmdprefix)
        self.next_id += 1
    
        # FIXME: we open a new socket for every readobj call...
        sock = UnixSocket(self.socket_path)
    
        buf = b''
    
        if self._notify is not None:
            # Opt into the notifications support
            self._writeobj(sock, {
                "jsonrpc": "2.0",
                "method": "notifications",
                "id": this_id + "+notify-enable",
                "params": {
                    "enable": True
                },
            })
            # FIXME: Notification schema support?
            _, buf = self._readobj(sock, buf)
    
        request = {
            "jsonrpc": "2.0",
            "method": method,
            "params": payload,
            "id": this_id,
        }
    
        if filter is None:
            filter = self._filter
        if filter is not None:
            request["filter"] = filter
    
        self._writeobj(sock, request)
        while True:
            resp, buf = self._readobj(sock, buf)
            id = resp.get("id", None)
            meth = resp.get("method", None)
    
            if meth == 'message' and self._notify is not None:
                n = resp['params']
                self._notify(
                    message=n.get('message', None),
                    progress=n.get('progress', None),
                    request=request
                )
                continue
    
            if meth is None or id is None:
                break
    
        self.logger.debug("Received response for %s call: %r", method, resp)
        if 'id' in resp and resp['id'] != this_id:
            raise ValueError("Malformed response, id is not {}: {}.".format(this_id, resp))
        sock.close()
    
        if not isinstance(resp, dict):
            raise TypeError("Malformed response, response is not a dictionary %s." % resp)
        elif "error" in resp:
>           raise RpcError(method, payload, resp['error'])
E           pyln.client.lightning.RpcError: RPC call failed: method: fundchannel, payload: 
{'id': '033845802d25b4e074ccfd7cd8b339a41dc75bf9978a034800444b51d42b07799a', 
'amount': 1000000, 'announce': True}, error: {'code': -1, 'message': 'Error broadcasting 
transaction: error code: -26\\nerror message:\\nmandatory-script-verify-flag-failed 
(Script failed an OP_EQUALVERIFY operation). Unsent tx discarded 
02000000000101c0556b0c2bb8df609521e70c64b96a5a15586ad854803efb06c05c6
57f46fc330100000000fdffffff0240420f00000000002200200b9d641c8a04f9eb11836
589c6f8a1b5e8fbd0f8d48031079d84b0e4cf0ba96b012f0f00000000002251209fa4d
24e9da43c5bf8fc0d9736d4e445238acd714d068116df5165d0791dba1d02473044022
05d23223acb837461a5e2289314c53316587e1b316c40357585c8d3add9486c72022
05f0337f04606f86594c754e00e2d32628eda4eef8c491d3b941bc7ab579c17f2012102
419e20f4442f5ef5500528fd0183a1d9b3910979af857ed7716e752cc2633c405e00000
0'}

contrib/pyln-client/pyln/client/lightning.py:428: RpcError

[enaples]

Maybe I messed up with something in the env configuration. I'm closing the issue for now.