I don't have the link to the github issue handy, but I remember that the key was to ask for a lower version of python and then supply the `--force-reinstall` param. The fact that it only happened to some students was evidence that conda wasn't as hermetically sealed as nix.

My real gripe is that in that issue, the app developer couldn't really help--since it was a packaging problem--and the conda folks were unaware because the users had gone straight to the app developer. If there must be a third party doing curation, it seems to me that they should be more narrowly focused on whatever particular suite of tools enables whatever particular group of people--not on individual packages.

I know that conda lets users do this too, but I don't think that the environments compose as well as they do with nix. If you want Jim's envioronment, but with Susie's custom build of foo-tool, you can just take both as inputs, overwrite foo-tool as desired, and output composition. Your maintenance burden remains small. If conda handles environments with this kind of compositional attitude, I'm unaware of it.