[Bug] Cannot install elephant with new Neo 0.7.2

[jpgill86]

Neo 0.7.2 was just released today (NeuralEnsemble/python-neo#687). However, until the typo that was fixed in #218 makes it onto PyPI in a new version of elephant, pip cannot resolve dependencies that include

neo>=0.7.2
elephant>=0.6.2

To fix this, elephant 0.6.3 (or 0.6.2.1) would need to be released including the fix from #218.

[jpgill86]

As an aside, I find the current requirement neo<0.8.0 for elephant to be very annoying.

I understand it's motivated by the intention to provide paired releases between elephant and Neo. However, if I have the development version of Neo installed, pip sees my Neo version as 0.8.0.dev, which violates the requirement neo<0.8.0, and pip automatically replaces it with an old version. Very obnoxious. When I manually reinstall Neo dev, I get this warning, though I can ignore it:

elephant 0.6.2 has requirement neo<0.8.0,>=0.7.1, but you'll have neo 0.8.0.dev0 which is incompatible.

EDIT: Interestingly, if the upper bound was changed from neo<0.8.0 to neo<0.8.0a, this particular conflict would go away. Anyway, I'm derailing my own issue... 🤣

[jpgill86]

Is anyone with the appropriate privileges willing to create a maintenance branch called "0.6.x" starting at the "v0.6.2" tag?

Once that is done, I can create a pull request against that branch that backports a67b33f into it. After it is merged, I will politely ask again if anyone is willing to create a release from the maintenance branch containing the fix (called 0.6.2.1 or 0.6.3, dealer's choice).

If a new version of elephant containing this tiny fix is released, I will finally be able to announce a new package that depends on it. Until then, my package cannot be installed from pip properly thanks to the conflict between elephant 0.6.2 and neo 0.7.2. 😢

[dizcza]

You introduced two issues here.

The first one, dependency conflict between elephant v0.6.2 and neo v0.7.2, will be fixed by creating a new elephant release v0.6.3 once #239 is merged.

Regarding the second issue, I don't know an easy fix for this. I tried to find out how other packages deal with dev version, but I have not found any mentions. Did you find the workaround neo<0.8.0a just by trying or you have a link that someone else does this? For me, neo<0.8.0a seems like a hack and is not obvious at all, and thus I don't want to include it.

[jpgill86]

You introduced two issues here.

Mea culpa.

The first one, dependency conflict between elephant v0.6.2 and neo v0.7.2, will be fixed by creating a new elephant release v0.6.3 once #239 is merged.

Thank you!

Regarding the second issue, I don't know an easy fix for this. I tried to find out how other packages deal with dev version, but I have not found any mentions. Did you find the workaround neo<0.8.0a just by trying or you have a link that someone else does this? For me, neo<0.8.0a seems like a hack and is not obvious at all, and thus I don't want to include it.

I can't remember exactly how I discovered it, I think I was working with some automated tool, perhaps pyoxidizer, which created a file for me containing a requirements spec like <0.8.0a, and it piqued my curiosity. I tried it locally for elephant and found it made a difference. I started drafting a separate issue containing a proposal to change how elephant specified requirements, but when I searched for references I found contradictory information!

For example, PEP 440 states that the version ordering should be 0.8.0.dev < 0.8.0a < 0.8.0. If that's how pip actually resolved version ordering, then we wouldn't have this problem in the first place!

So I decided to drop it and deleted my draft. 🤣 Sorry for the time you have already spent looking into that issue with me. I agree that it seems like a hack. Perhaps tomorrow the pip team will realize they aren't following PEP 440 and will change it, and adopting the hack for elephant will have been a mistake. I'll find a way to continue living with neo<0.8.0 in my dev environment. 😊

However, the first issue of conflicting versions is harder to work around, since it affects how my users install my package, rather than just how I set up my local dev environment. I appreciate your willingness to create a new release soon that includes the fix in #218. Thanks again!

[dizcza]

1. The release v0.6.3 is published.
2. I checked the pep 440 about version resolving you linked and I also find that pip does not follow it. Maybe, one should fire an issue for pip or at least ask for clarification. I don't feel I'll do it soon. For now, I leave it as it is, keeping it running in the back of my mind.

[jpgill86]

Thank you for the release!