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Error in retrieveDescriptors() during subscribe #395
Description
Version: 2.3.4
I updated from 2.3.2 to 2.3.4 and one of my target devices fails during a subscribe with:
E (16166) NimBLERemoteCharacteristic: ble_gattc_disc_all_dscs: rc=3 One or more arguments are invalid
So, I dutifully hacked in some debug to dump the arguments:
...
E (15958) NimBLERemoteCharacteristic: 1 = 0, 2 = 77, 3 = 83, 4 = 0x4011e454, 5 = 0x3ffd9bb4
...
E (16158) NimBLERemoteCharacteristic: 1 = 0, 2 = 82, 3 = 76, 4 = 0x4011e454, 5 = 0x3ffd9bb4
E (16166) NimBLERemoteCharacteristic: ble_gattc_disc_all_dscs: rc=3 One or more arguments are invalid
Note that argument 2, the handle, is now beyond the 'end handle' returned by getRemoteService()->getEndHandle() and the end handle has changed.
The usage pattern is:
- pChr1 = pSvc->getCharacteristic(UUID1);
- pChr2 = pSvc->getCharacteristic(UUID2);
- pChr2->subscribe(UUID2A);
- pChr1->subscribe(UUID1A);
As this was working before, I backed up to 2.3.3 and got this output:
...
E (18026) NimBLERemoteCharacteristic: 1 = 0, 2 = 77, 3 = 83, 4 = 0x4011e3c4, 5 = 0x3ffd9c24
...
E (18227) NimBLERemoteCharacteristic: 1 = 0, 2 = 82, 3 = 83, 4 = 0x4011e3c4, 5 = 0x3ffd9c24
Note the end handle has not changed as before in the failure case.
I didn't bisect to confirm, but I'm fairly sure this is caused by #387.
Activity
[-]Error in attribute discovery[/-][+]Error in retrieveDescriptors() during subscribe[/+]gkoh commentedon Feb 19, 2026
After poking around, I hacked a bit more and looks like the iteration loop to establish the end handle is getting limited:
(I couldn't work out which combination of LOG to up to debug, so I just hacked it to ERROR ...)
h2zero commentedon Mar 18, 2026
@gkoh Is this still an issue?
gkoh commentedon Mar 26, 2026
Just retested with 2.4.0.
Yes, this is still an issue, let me know what I can add to help narrow this down (is it just me?).
h2zero commentedon Mar 27, 2026
If you'd like to take a stab at finding this I'd appreciate it, otherwise I'll see what I can do after I get some other tweaks finished.
gkoh commentedon Mar 27, 2026
I'll give it a bash, if nothing else I should be able to gather more info for debug.
gkoh commentedon Mar 28, 2026
Caveat: I have approximately 0 knowledge of the hierarchy of characteristics and descriptors.
I added more handle debug:
As noted prior, my app attempts to subscribe to two characteristics, serially.
From the above, it looks to me like the loop assumes the handles in the descriptor vector are numerically sorted.
The first subscribe shows the iterator loops through handles in the order '82, 77'.
On the second subscribe, it hits the end, but since the 'next' characteristic has a lower handle range, the 'next - 1' approach results in
endHandleless thangetHandle().gkoh commentedon Mar 29, 2026
Can confirm, #415 fixes this.
Thank you!