regex_core.error: multiple repeat at position 1146

[Russell-Jones]

I was just playing with pygrok; I ran the following, which might be a useful basis for a test, and got the titular error.

#!/usr/bin/env python3
import os
import gc
import itertools as it
import pygrok as pg

fs = it.chain(*(os.scandir(d) for d in 
                pg.DEFAULT_PATTERNS_DIRS))
ps = it.chain(*(open(f.path).readlines() for f in fs))
gc.collect() # release file descriptors, I think. xonsh got upset without it.

for p in ps:
    try:
        pg.Grok(p)
    except Exception as e:
        print(p, e)

The offending pattern is

SHOREWALL (%{SYSLOGTIMESTAMP:timestamp}) (%{WORD:nf_host}) kernel:.*Shorewall:(%{WORD:nf_action1})?:(%{WORD:nf_action2})?.*IN=(%{USERNAME:nf_in_interface})?.*(OUT= *MAC=(%{COMMONMAC:nf_dst_mac}):(%{COMMONMAC:nf_src_mac})?|OUT=%{USERNAME:nf_out_interface}).*SRC=(%{IPV4:nf_src_ip}).*DST=(%{IPV4:nf_dst_ip}).*LEN=(%{WORD:nf_len}).?*TOS=(%{WORD:nf_tos}).?*PREC=(%{WORD:nf_prec}).?*TTL=(%{INT:nf_ttl}).?*ID=(%{INT:nf_id}).?*PROTO=(%{WORD:nf_protocol}).?*SPT=(%{INT:nf_src_port}?.*DPT=%{INT:nf_dst_port}?.*)