[Nix-dev] how to overwrite a derivation in nix

[Sergey]

On 11.01.2014 05:09, phreedom at yandex.ru wrote:
> On Saturday, January 11, 2014 01:04:48 AM Sergey wrote:
>> On 10.01.2014 15:57, Marc Weber wrote:
>>> option 1: use ~/.nixpkgs/config.nix, see wiki "how to keep multiple
>>> packages up to date" or such.
>>>
>>> option 2: use applyGlobalOverrides
>>> problem: its not exposed by pkgs AFAIK
>>>
>>> option 3: when importing nipkgs pass config.nix (like option 1)
>>>
>>> option 4: use deepOverride (see lib.misc.nix)
>>>
>>> Then it would look like
>>> something_having_thunar_as_dep.deepOverride  {
>>>
>>>     thunar = patch-thunar-here
>>>
>>> }
>>>
>>> Now it looks like you don't want to "override", instead you want to
>>> reuse a build and add a patch only giving it a new name, this is done by
>>> overrideDerivation found in lib/customization.nix
>>>
>>> thunar is in xfce/core/thunar, and no top-level in all-packages.nix
>>> and eg ./pkgs/desktops/xfce/core/xfdesktop.nix|2| depends on it.
>>>
>>> Thus you might need any of the deep overriding methods listed above if
>>> you want packages to change depending on it.
>>>
>>> Eventually the most simple thing is to create a git topic branch and
>>> just apply your change.
>> Yep, I do the job in my local branch, which I don't  plan to merge into
>> upstream. But I also want to minimize the changes in the nixpkgs folder,
>> in particular, I'd like to avoid copying an existing derivation if I
>> don't need a specific version of the application it defines. Of cause,
>> ideally, I'd like to avoid touching the tree at all.
>>
>>> Marc Weber
>>> _______________________________________________
>>> nix-dev mailing list
>>> nix-dev at lists.science.uu.nl
>>> http://lists.science.uu.nl/mailman/listinfo/nix-dev
>> overrideDerivation does what I expected, thanks! Looks like I don't need
>> deepOverride right now. There is a problem, however, which prevents me
>> from keeping my changes completely separate from the nixpkgs tree.  It
>> is on a nixos level. Basically, I've ended up with the following setup:
>>
>> # nixos/services/x11/desktopManagers/xfce.nix
>>
>> environment.systemPackages = [
>>     ...
>>     pkgs.xfce.thunar
>>     ...
>> ];
>>
>> # my_config.nix
>>
>> let
>>     thunar_uca = pkgs.lib.hiPrio (pkgs.lib.overrideDerivation
>> pkgs.xfce.thunar (a:{
>>       name = a.name + "-uca";
>>       prePatch = ''
>>         ./tweak-sources.sh
>>       '';
>>     }));
>> in
>>
>> environment.systemPackages = [
>>     ...
>>     thunar_uca
>>     ...
>> ];
>>
>> Here I have two different conflicting packages sitting in the
>> environment.systemPackages after merging. hiPrio doesn't help me here
>> probably because it affects nix-env only. If there had been a method of
>> filtering out original pkgs.xfce.thunar from systemPackages list, I
>> would have done my hack without touching nixpkgs/. Is it possible? For
>> now I have a patch which does some minimal changes [1] there.
> you simply need to override thunar instead of adding another package.
> xfce =pkgs.xfce // {thunar = overrideDerivation pkgs.xfce.thunar ...
Awesome, Thanks!