I’m having numerous problems every time I rebuild due to an unmaintained and unsafe library: qtwebengine-5.15.19.
It either breaks or slow down the rebuilds.
I found ways to check dependencies from the top-down with nix why-depends and nix-tree, but I was wondering if there is a way or there are tools to check dependencies from the bottom-up? Like, in this case, I would like to see what depends on qtw and either see if that can be fixed or straight up remove the package if that’s needed.
nix why-depends --all /run/current-system <store path of qtwebengine> tells you exactly that. It should give you the tree with intermediaries, removing those will remove the dep.
Flip the order if you want to know why qtwebengine depends on your system (it doesn’t).
I think you want nix-store --query --referrers /nix/store/<hash>-qtwebengine or nix-store --query --referrer-closure /nix/store/<hash>-qtwebengine
There’s also another option, if you like nix-tree.
(Note: You can press ? to open up the help window to see all the available shortcuts.)
/ to open up the search modalqtwebengine-5)Enter. Immediate parents will be listed at the bottom of the screen.w to open the why-depends modal, which will look something like this (I used waydroid instead for example purposes):You can scroll up/down, page-up/page-down, and even move left/right in the modal, but the left-right scrolling feels a bit slow, I’d suggest just maximizing the window as much as possible.
Thank you very much, This worked easily and neatly and I found the culprit.
Thank you for this, I just found the command below a bit more straightforward.
I couldn’t use this command because I couldn’t install anything due to the issue I shared. But now, I can fix my build and eventually give a go to nix-tree. I found out about it as I was looking for a solution for my issue, so it wasn’t in my packages yet.
nix-shell -p nix-tree makes nix-tree available in a new temporary shell.
I keep forgetting that’s an option on NixOS 
