pigpio: Wave deletion does not happen as expected

I must first say im impressed by this library. Im using it for a hobby CNC project and it makes it possible to do parallel execution of waves for several motors based on GPIO’s.

But i think there is an issue with wave deletion.
When using a python add-create-send-delete loop for waves, i cannot always remove the completed waves. It leads to ‘No more CBs for waveform’ when creating new waves.

I can recreate the problem with a simple loop. When the deletion does not happen, the wave id increases continuously.

and here is the code

import pigpio
import time
import random

pi = pigpio.pi('navio2.local')

# system info
print 'pigpiod version: {}'.format(pi.get_pigpio_version())  # 61
print 'pigpio.py version: {}'.format(pigpio.VERSION)  # 1.36
print 'wave_get_max_pulses: {}'.format(pi.wave_get_max_pulses()) # 12000

gpio = [19, 5, 25]

total = 30000
blocksize = 3000
iter = total / blocksize

waves = []
wavepos = 0


"""
When running with different delay, the loop fails with pigpio.error: No more CBs 
for waveform'.

But when running with equal delays, the loop completes. 
Proberbly because the waves are reused in gpioWaveCreate.
"""
delays_that_fails = [200, 0]       # fails
equal_delay_does_not_fail = [200]  # to se an execution as expected

delay = delays_that_fails

for p in range(total / 6):

    waves.append(pigpio.pulse(1 << gpio[0], 0, random.choice(delay)))
    waves.append(pigpio.pulse(1 << gpio[1], 0, random.choice(delay)))
    waves.append(pigpio.pulse(1 << gpio[2], 0, random.choice(delay)))

    waves.append(pigpio.pulse(0, 1 << gpio[0], random.choice(delay)))
    waves.append(pigpio.pulse(0, 1 << gpio[1], random.choice(delay)))
    waves.append(pigpio.pulse(0, 1 << gpio[2], random.choice(delay)))

print 'pulses: {}'.format(len(waves))

pi.wave_clear()
iteration = 0
old_id = -1

# add-create-send-delete loop with a sleep delay after send
while wavepos <= len(waves) - blocksize:

    new_wavepos = wavepos + blocksize
    slice = waves[wavepos:new_wavepos]
    wavepos = new_wavepos

    iteration += 1
    print 'iteration %s' % iteration

    pi.wave_add_generic(slice)

    new_id = pi.wave_create()
    pi.wave_send_using_mode(new_id, pigpio.WAVE_MODE_ONE_SHOT_SYNC)

    while pi.wave_tx_at() != new_id:
        time.sleep(0.01)

    if old_id >= 0:
        print 'delete wave id %s' % old_id
        pi.wave_delete(old_id)

    old_id = new_id

pi.stop()

print 'complete'