Please don't merge quite yet-- they changed details in the dbus interface, so this update breaks iwd usage with NetworkManager.

I put together this fix which does the job for me, but would ideally have something more official and perhaps more complete ;).
https://github.com/dtzWill/nixpkgs/blob/96213b0560d8d8b8284ec2500c1b48af9aa51cf1/pkgs/tools/networking/network-manager/iwd-new-root-path.patch

The #iwd channel on freenode has some chat about this today, but haven't been following too closely (yet).

Also at some point I had to add this, I believe it's in the 1.0 release:

    "--with-systemd-networkdir=${placeholder "out"}/lib/systemd/system/"

And we may consider teaching NixOS to prefer a certain value for persistent naming when using iwd (they want it off).

Oh and if we currently do much for generating config, they changed the keys to be camelcase and often rewording. It's not suitable for nixpkgs master yet, but my iwd module has a bit more beef in this area, and demonstrates what I mean:

dtzWill@57b8f5e#diff-90906f69858d618dcfe8c39518f69a6e

Thank you both for doing this work!

Oh and if we currently do much for generating config, they changed the keys to be camelcase and often rewording. It's not suitable for nixpkgs master yet, but my iwd module has a bit more beef in this area, and demonstrates what I mean:

dtzWill@57b8f5e#diff-90906f69858d618dcfe8c39518f69a6e

Oooh, we should try to get some of that in nixpkgs. I believe people have been having issues because there's no config installed for iwd, and dhcp woes/resolvconf.

What exactly is broken. I am using this right now with networkmanager and have not had any issues for the last few days. Also, I set --with-systemd-networkdir=${placeholder "out"}/lib/systemd/network/ already. I'd like to reproduce so I can fix. Thanks

note, it looks like the upcoming NM release has a fix for IWD 1.0. Not sure if it's relevant here or not, but seemed like a shot: NetworkManager/NetworkManager@186d22a

iwd was bumped to 1.1 on master with 09f1e09, so I guess this is obsolete now?

I thought this was blocked because of incompatibilities with Network Manager's API.. Does it mean NM's users who use IWD will get disconnected in their next nixos-rebuild upgrade? Or did they patch NM as well?

I thought this was blocked because of incompatibilities with Network Manager's API.. Does it mean NM's users who use IWD will get disconnected in their next nixos-rebuild upgrade? Or did they patch NM as well?

Well I don't think NM was patched. They can still roll back though, so its not too bad I guess.

The Networkmanager patch could be cherry-picked.

Yes, and the NM patch is also backwards compatible (an improvement on what I originally put together and linked earlier), so safe to pick. If there's not a tagged release with this yet, of course :).

The fix is in https://gitlab.freedesktop.org/NetworkManager/NetworkManager/blob/1.20.6/NEWS#L9 which there's a PR for #73598. It will have to to staging though

Going to close as obsolete. Sorry about a committer pushing this, duplicated work is frequent in nixpkgs unfortunately.

just came here because I got hit by this issue. The NetworkManager upgrade hasn't left the staging branch yet.

So NetworkManager was patched to staging while iwd was updated in master? And now you can't NetworkManager with IWD?

Correct.
I tried reverting the IWD upgrade. This doesn't work, there were some build failures, I don't remember the details. Presumably some other packages are now depending on the latest IWD.
I tried cherry-picking the NetworkManager upgrade. This builds fine but doesn't solve the problem. Now I get this new error instead:

Nov 27 15:00:05 no1 NetworkManager[1026]: <warn>  [1574863205.7424] device (wlp5s0): No agents were available for this request.
Nov 27 15:00:05 no1 NetworkManager[1026]: <error> [1574863205.7425] device (wlp5s0): Activation: (wifi) Network.Connect failed: GDBus.Error:net.connman.iwd.Aborted: Operation aborted
Nov 27 15:00:05 no1 NetworkManager[1026]: <warn>  [1574863205.7433] device (wlp5s0): Activation: failed for connection 'Leazero'