Segmentation fault when there are trailing zeros in numeric values

[niranjan94]

• asyncpg version: 0.20.0
• PostgreSQL version: 11 & 12
• Do you use a PostgreSQL SaaS? If so, which? Can you reproduce
  the issue with a local PostgreSQL install?: AWS RDS (pg 11) & Local (pg 12)
• Python version: 3.8.1
• Platform: Mac & Debian 10
• Do you use pgbouncer?: No
• Did you install asyncpg with pip?: Yes
• If you built asyncpg locally, which version of Cython did you use?: Did not build locally
• Can the issue be reproduced under both asyncio and
  uvloop?: Yes

---

asyncpg fails in a segmentation fault when querying rows that contain large numeric values with trailing zeros.

import asyncio
import asyncpg


async def run():
 conn = await asyncpg.connect(
 user='niranjan', password='password',
 database='niranjan', host='192.168.65.2'
 )
 await conn.fetch("""
 SELECT 1000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000.00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000::numeric
 """)
 await conn.close()


if __name__ == '__main__':
 asyncio.run(run())

This results in

root@docker-desktop:/data# python -q -X faulthandler overflow.py 
Fatal Python error: Segmentation fault

Current thread 0x00007fe4aeca6740 (most recent call first):
 File "/usr/local/lib/python3.8/asyncio/selector_events.py", line 860 in _read_ready__data_received
 File "/usr/local/lib/python3.8/asyncio/selector_events.py", line 803 in _read_ready
 File "/usr/local/lib/python3.8/asyncio/events.py", line 81 in _run
 File "/usr/local/lib/python3.8/asyncio/base_events.py", line 1855 in _run_once
 File "/usr/local/lib/python3.8/asyncio/base_events.py", line 567 in run_forever
 File "/usr/local/lib/python3.8/asyncio/base_events.py", line 599 in run_until_complete
 File "/usr/local/lib/python3.8/asyncio/runners.py", line 43 in run
 File "overflow.py", line 17 in <module>
Segmentation fault

---

But, adding at least a single number at the end of the trailing zeros ensure the query runs correctly.

SELECT 1000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000.000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001::numeric