Installation fails due to conflicting backoff version

[NeolithEra]

Hi, users are unable to run target-datadotworld due to dependency conflict with backoff package. As shown in the following full dependency graph of target-datadotworld, target-datadotworld requires backoff <2.0a,>=1.3.0，while singer-python requires backoff ==1.8.0.

According to pip’s “first found wins” installation strategy, backoff 1.10.0 is the actually installed version. However, backoff 1.10.0 does not satisfy ==1.8.0.

Dependency tree-----------

target-datadotworld - 1.0.1
| +- backoff(install version:1.10.0 version range:<2.0a,>=1.3.0)
| +- click(install version:7.0 version range:<7.0a,>=6.7)
| +- jsonschema(install version:3.2.0 version range:<3.0a,>=2.6.0)
| +- pyjwt(install version:1.7.1 version range:>=1.5.3,<2.0a)
| +- requests(install version:2.22.0 version range:<3.0a,>=2.4.0)
| | +- certifi(install version:2019.11.28 version range:>=2017.4.17)
| | +- chardet(install version:3.0.4 version range:<3.1.0,>=3.0.2)
| | +- idna(install version:2.8 version range:>=2.5,<2.9)
| | +- urllib3(install version:1.25.7 version range:<1.26,>=1.21.1)
| +- singer-python(install version:5.9.0 version range:<6.0a,>=5.0.4)
| | +- backoff(install version:1.8.0 version range:==1.8.0)
| | +- ciso8601(install version:2.1.2 version range:*)
| | +- jsonschema(install version:2.6.0 version range:==2.6.0)
| | +- python-dateutil(install version:2.8.1 version range:>=2.6.0)
| | +- pytz(install version:2018.4 version range:==2018.4)
| | +- simplejson(install version:3.11.1 version range:==3.11.1)

Thanks for your help.
Best,
Neolith

[NeolithEra]

Suggested Solution

1. Fix your direct dependency to be backoff ==1.8.0. I have checked this revision will not affect your downstream projects now.
2. Ask your upstream project singer-python to loose the version range of backoff.
3. Remove your direct dependency backoff, and use backoff transitively introduced by singer-python.

@rflprr Which solution do you prefer, 1, 2 or 3?
Please let me know your choice. I can submit a PR to solve this issue.