Python on Heroku SyntaxError: future feature annotations is not defined.

Question

我试图向Heroka发起机器人电报，但日志显示SyntaxError: future feature annotations is not defined.How can this be fixed？

aiogram==2.8
aiohttp==3.6.2
async-timeout==3.0.1
attrs==19.3.0
Babel==2.8.0
certifi==2020.4.5.1
chardet==3.0.4
emoji==0.5.4
idna==2.9
multidict==4.7.6
numpy==1.17.3
opencv-python==4.1.1.26
pytz==2020.1
requests==2.23.0
urllib3==1.25.9
yarl==1.4.2

"""日志实例""

2020-06-03T10:47:28.473585+00:00 heroku[worker.1]: State changed from crashed to starting
2020-06-03T10:47:34.163665+00:00 heroku[worker.1]: Starting process with command `python3 main.py`
2020-06-03T10:47:34.765639+00:00 heroku[worker.1]: State changed from starting to up
2020-06-03T10:47:37.023965+00:00 app[worker.1]: Traceback (most recent call last):
2020-06-03T10:47:37.023998+00:00 app[worker.1]: File "main.py", line 1, in <module>
2020-06-03T10:47:37.024120+00:00 app[worker.1]: from aiogram import Bot, types
2020-06-03T10:47:37.024138+00:00 app[worker.1]: File "/app/.heroku/python/lib/python3.6/site-packages/aiogram/__init__.py", line 4, in <module>
2020-06-03T10:47:37.024241+00:00 app[worker.1]: from . import bot
2020-06-03T10:47:37.024241+00:00 app[worker.1]: File "/app/.heroku/python/lib/python3.6/site-packages/aiogram/bot/__init__.py", line 1, in <module>
2020-06-03T10:47:37.024340+00:00 app[worker.1]: from . import api
2020-06-03T10:47:37.024343+00:00 app[worker.1]: File "/app/.heroku/python/lib/python3.6/site-packages/aiogram/bot/api.py", line 7, in <module>
2020-06-03T10:47:37.024449+00:00 app[worker.1]: from .. import types
2020-06-03T10:47:37.024451+00:00 app[worker.1]: File "/app/.heroku/python/lib/python3.6/site-packages/aiogram/types/__init__.py", line 1, in <module>
2020-06-03T10:47:37.024554+00:00 app[worker.1]: from . import base
2020-06-03T10:47:37.024570+00:00 app[worker.1]: File "/app/.heroku/python/lib/python3.6/site-packages/aiogram/types/base.py", line 1
2020-06-03T10:47:37.024570+00:00 app[worker.1]: from __future__ import annotations
2020-06-03T10:47:37.024589+00:00 app[worker.1]: ^
2020-06-03T10:47:37.024590+00:00 app[worker.1]: SyntaxError: future feature annotations is not defined
2020-06-03T10:47:37.104216+00:00 heroku[worker.1]: Process exited with status 1
2020-06-03T10:47:37.150349+00:00 heroku[worker.1]: State changed from up to crashed

"""

Answer 1

好的，如果你有同样的问题，在你的项目文件 "runtime.txt "中写上你需要的python版本（对于exmaple，python-3.7.7）。https:/devcenter.heroku.comarticlespython-runtimes(运行时)