Hi, Ricardo Wurmus skribis: > In this case it is not entirely clear that the existing python-requests > package in the profile is “old”. The version looks the same and the > hash is opaque. > > Would it be possible to record something about the Guix version that was > used to install a package? Then we could say: > > An older variant of python-requests is installed in this profile > (propagated from package “foo-bar”) and conflicts with a newer variant > (propagated from package “python-twine”). When the version numbers are the same, we cannot tell whether a variant is “older”, we can just tell that it’s different. Also, I find it useful to see the propagation stack as is currently the case. With the patch below, I get: --8<---------------cut here---------------start------------->8--- $ ./pre-inst-env guix package -p foo -i python@2 python The following packages will be installed: python 2.7.13 /gnu/store/vysfxizaddh1q8s5qjgbdkzxx0585dzi-python-2.7.13 python 3.5.3 /gnu/store/m4rdgmvdqcxs2zhv42idnz1s1w391i8j-python-3.5.3 guix package: error: profile contains conflicting entries for python:out guix package: error: first entry: python@2.7.13 /gnu/store/vysfxizaddh1q8s5qjgbdkzxx0585dzi-python-2.7.13 guix package: error: second entry: python@3.5.3 /gnu/store/m4rdgmvdqcxs2zhv42idnz1s1w391i8j-python-3.5.3 hint: You cannot have two different versions or variants of `python' in the same profile. --8<---------------cut here---------------end--------------->8--- and: --8<---------------cut here---------------start------------->8--- $ ./pre-inst-env guix package -i guile-cairo -p foo --no-grafts The following package will be installed: guile-cairo 1.4.1 /gnu/store/dsdbp9sqla6zz2skljlcr5zfjyzvargf-guile-cairo-1.4.1 guix package: error: profile contains conflicting entries for cairo:out guix package: error: first entry: cairo@1.14.10 /gnu/store/c4vl4hw5jccg0b23sfvs0kdnfdbxdlgm-cairo-1.14.10 guix package: error: ... propagated from guile-cairo@1.4.1 guix package: error: second entry: cairo@1.14.10 /gnu/store/nwxv9s2q8pi0m6gn6fyidpj8442dwp6f-cairo-1.14.10 guix package: error: ... propagated from cairomm@1.12.2 hint: Try upgrading both `guile-cairo' and `cairomm', or remove one of them from the profile. --8<---------------cut here---------------end--------------->8--- How does that sound? We could further refine the hint to suggest using ‘guix package -m’, though I’m not sure if it’d be a useful hint (it’s a useful recommendation, but not necessarily good as a “fix hint.”) Thoughts? Thanks, Ludo’.