deleteAllBonds() apparently leaves stale SM state — re-pairing fails within same boot cycle (workaround: iterate deleteBond())

[HijelHub]

Environment

NimBLE-Arduino 2.3.9
ESP32 (Arduino Core 3.3.7)
Host: iOS (confirmed); likely affects others too
Security mode: Passkey (MITM + SC + Bond)

Behaviour

After calling NimBLEDevice::deleteAllBonds(), attempting to re-pair within the same boot cycle fails consistently. The passkey is generated and displayed correctly, the pairing prompt appears, but pairing immediately fails with onPairingComplete(false). The device loops in connect/fail/disconnect endlessly. Any reboot of the ESP32 clears the problem and the first pairing attempt after boot always succeeds — but only once.

Possible Cause

deleteAllBonds() calls ble_store_clear() internally, which wipes the NVS bond records but apparently does not flush the NimBLE Security Manager's in-memory per-peer state. The stale SM context causes the pairing handshake to fail when device attempts to re-pair against the same peer address within the same session.

Workaround

Instead of calling deleteAllBonds(), iterate in reverse through all bonded peers and call deleteBond() on each individually. deleteBond() routes through ble_gap_unpair() and seems to flush properly. Reverse iteration avoids index-shift issues as entries are removed.

int numBonds = NimBLEDevice::getNumBonds();
for (int i = numBonds - 1; i >= 0; i--) {
    NimBLEDevice::deleteBond(NimBLEDevice::getBondedAddress(i));
}

This workaround was confirmed to resolve iOS re-pairing failure within the same boot cycle. The fix likely applies to other environments as well, though not tested.

Suggestion

deleteAllBonds() itself could be updated to use this loop internally instead of calling ble_store_clear() directly, so callers get correct SM state cleanup without needing to work around it manually.

[h2zero]

Thanks, this looks like an upstream bug as well, so I will present it there also.
I will adapt the current code to use your suggestion shortly.