[Nix-dev] CMake broken

[Evgeny Egorochkin]

В сообщении от Понедельник 27 сентября 2010 15:49:47 автор Peter Simons 
написал:
> Hi,
> 
> the recent changes to the CMake expression break the build for me on
> Linux/x86_64 when useNcurses is 'false'. This setting means that CMake
> won't have ncurses in buildInputs, but the build seems to expect it
> anyway and fails trying to compile ncurses-specific modules.
> 
> Generally speaking, I find these changes somewhat dubious. For instance, we
> now have three different versions of CMake defined in all-packages.nix:
> 
>   cmake = callPackage ../development/tools/build-managers/cmake { };
> 
>   cmakeCurses = cmake.override { useNcurses = true; };
> 
>   cmakeWithGui = cmakeCurses.override { useQt4 = true; };
> 
> However, all of these expressions have the same name! That's an ambiguous
> and undesirable situation. Also, where is the version that has support for
> both qt and ncurses?
> 
> Last but not least, I'm not particularly fond of expressions that require
> 'useDepXY' flags. IMHO, it's both easier and more intuitive to pass 'xy =
> null' to disable support for that particular dependency.

If all you want is disable the feature, you are right. however if you want to 
enable/reenable feature, it's not as easy.

In theory, useFeature flags are more correct in that you can have by default 
{useFeature=false, feature} and packages that need it can override the flag, 
it's easier for users to enable experimental/unstable features this way.

-- 
Evgeny