[Nix-dev] nix modules: Unsetting attrsOf options?

[Rickard Nilsson]

On 09/07/2016 11:54 AM, 4levels wrote:
> Hi Rickard,
>
> All I can think of currently is that you could create a new config
> variable using filterAttrs to keep only the information you need.
> Not sure if this solves your question though as I'm not aware if you can
> use another variable in your scenario.

Using filterAttrs like this would introduce an infinite recursion, I think:

config = {
   myattrs = filterAttrs (k: _: k != "a") config.myattrs;
}

But maybe that wasn't what you had in mind.

For the issue that spurred this question I have now added an "enable" 
option for the attributes, see: https://github.com/NixOS/nixpkgs/pull/18391

However, that is not a general solution to this problem, so any further 
hints are welcome.

   / Rickard


> Kind regards,
>
> Erik
>
> On Wed, Sep 7, 2016 at 12:35 AM Rickard Nilsson
> <rickard.nilsson at telia.com <mailto:rickard.nilsson at telia.com>> wrote:
>
>     Is it possible to unset an attrsOf option? Say I import a module that
>     looks like this:
>
>     options = {
>        myattrs = mkOption {
>          type = types.attrsOf ...
>          default = {};
>        };
>     }
>
>     config = {
>        myattrs = {
>          a = ...
>          b = ...
>        };
>     };
>
>     And then I want to remove the "a" attribute in the importing config:
>
>     config = {
>        myattrs.a = mkForce ...
>     }
>
>     Is that possible in any way?
>
>
>        / Rickard
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