nixos/nixos-option: don't abort in case of evaluation errors #43147
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infinisil
reviewed
Jul 10, 2018
| @@ -87,7 +92,6 @@ EOF | |||
| ' <<EOF | |||
| $result | |||
| EOF | |||
| return 1; | |||
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good catch, that shouldn't be part of the patch :)
This ensures that after evalNix the script doesn't abort. If e.g. the evaluation of the current value of an option fails the script shouldn't stop, but should print additional properties of the option instead.
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Shouldn't the error still be propagated somehow? E.g. with an $error variable, which, when set, will return 1 at the very end, and intermediate failures will set it.
matthewbauer
approved these changes
Jul 11, 2018
When running e.g. `nixos-option boot.kernelPackages` I get an output
like this on the current unstable channel (18.09pre144959.be1461fc0ab):
```
$ nixos-option boot.kernelPackages
Value:
*exit 1*
```
This is fairly counter-intuitive as I have no clue what might went
wrong. `strace` delivers an output like this:
```
read(3, "error: Package \342\200\230cryptodev-linu"..., 128) = 128
read(3, "ux/cryptodev/default.nix:22 is m"..., 128) = 128
read(3, "lowBroken = true; }\nin configura"..., 128) = 128
read(3, "you can add\n { allowBroken = tr"..., 128) = 128
read(3, "n)\n", 128) = 3
read(3, "", 128) = 0
```
`nixos-option` evaluates the system config using `nix-instantiate` which
might break when the evaluation fails (e.g. due to broken or unfree
packages that are prohibited to evaluate by default). The script aborts
due to the shebang `@shell@ -e`.
In order to ensure that no unexpected
behavior occurs due to removing `-e` from the interpreter the easiest
way to work around this was to wrap `nix-instantiate` in `evalNix()`
with a `set +e`. The function checks the success of the evaluation with
`$?` in the end. Additionally `evalNix` shouldn't break, if one
evaluation (e.g. the values that contain a package set by default) to
return additional information like a description.
With the change `nixos-option boot.kernelPackages` delivers the
following output for me:
```
Value:
error: Package ‘cryptodev-linux-1.9-4.14.52’ in /nix/store/47z2s8cwppymmgzw6n7pbcashikyk5jk-nixos/nixos/pkgs/os-specific/linux/cryptodev/default.nix:22 is marked as broken, refusing to evaluate.
Default:
{ __unfix__ = <LAMBDA>; acpi_call = <CODE>; amdgpu-pro = <CODE>; ati_drivers_x11 = <CODE>; batman_adv = <CODE>; bbswitch = <CODE>; bcc = <CODE>; beegfs-module = <CODE>; blcr = <CODE>; broadcom_sta = <CODE>; callPackage = <CODE>; cpupower = <CODE>; cryptodev = <CODE>; dpdk = <CODE>; e1000e = <CODE>; ena = <CODE>; evdi = <CODE>; exfat-nofuse = <CODE>; extend = <CODE>; facetimehd = <CODE>; fusionio-vsl = <CODE>; hyperv-daemons = <CODE>; ixgbevf = <CODE>; jool = <CODE>; kernel = <CODE>; lttng-modules = <CODE>; mba6x_bl = <CODE>; mwprocapture = <CODE>; mxu11x0 = <CODE>; ndiswrapper = <CODE>; netatop = <CODE>; nvidiaPackages = <CODE>; nvidia_x11 = <CODE>; nvidia_x11_beta = <CODE>; nvidia_x11_legacy304 = <CODE>; nvidia_x11_legacy340 = <CODE>; nvidiabl = <CODE>; odp-dpdk = <CODE>; openafs = <CODE>; openafs_1_8 = <CODE>; perf = <CODE>; phc-intel = <CODE>; pktgen = <CODE>; ply = <CODE>; prl-tools = <CODE>; recurseForDerivations = true; rtl8192eu = <CODE>; rtl8723bs = <CODE>; rtl8812au = <CODE>; rtl8814au = <CODE>; rtlwifi_new = <CODE>; sch_cake = <CODE>; spl = <CODE>; splLegacyCrypto = <CODE>; splStable = <CODE>; splUnstable = <CODE>; stdenv = <CODE>; sysdig = <CODE>; systemtap = <CODE>; tbs = <CODE>; tmon = <CODE>; tp_smapi = <CODE>; usbip = <CODE>; v4l2loopback = <CODE>; v86d = <CODE>; vhba = <CODE>; virtualbox = <CODE>; virtualboxGuestAdditions = <CODE>; wireguard = <CODE>; x86_energy_perf_policy = <CODE>; zfs = <CODE>; zfsLegacyCrypto = <CODE>; zfsStable = <CODE>; zfsUnstable = <CODE>; }
Example:
{ _type = "literalExample"; text = "pkgs.linuxPackages_2_6_25"; }
Description:
"This option allows you to override the Linux kernel used by\nNixOS. Since things like external kernel module packages are\ntied to the kernel you're using, it also overrides those.\nThis option is a function that takes Nixpkgs as an argument\n(as a convenience), and returns an attribute set containing at\nthe very least an attribute <varname>kernel</varname>.\nAdditional attributes may be needed depending on your\nconfiguration. For instance, if you use the NVIDIA X driver,\nthen it also needs to contain an attribute\n<varname>nvidia_x11</varname>.\n"
Declared by:
"/nix/var/nix/profiles/per-user/root/channels/nixos/nixpkgs/nixos/modules/system/boot/kernel.nix"
Defined by:
"/home/ma27/Projects/nixos-config/system/boot.nix"
```
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|
@infinisil with my patch the evaluation is resumed, if one value fails to evaluate, the other's can still be returned. You're absolutely right though, when one evaluation breaks, I shouldn't get a zero exit code. Now Is this ok for you now? :) |
infinisil
approved these changes
Jul 11, 2018
|
@nbp would you mind having a look at this? :) |
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Motivation for this change
When running e.g.
nixos-option boot.kernelPackagesI get an outputlike this on the current unstable channel (18.09pre144959.be1461fc0ab):
This is fairly counter-intuitive as I have no clue what might went
wrong.
stracedelivers an output like this:nixos-optionevaluates the system config usingnix-instantiatewhichmight break when the evaluation fails (e.g. due to broken or unfree
packages that are prohibited to evaluate by default). The script aborts
due to the shebang
@shell@ -e.In order to ensure that no unexpected
behavior occurs due to removing
-efrom the interpreter the easiestway to work around this was to wrap
nix-instantiateinevalNix()with a
set +e. The function checks the success of the evaluation with$?in the end. AdditionallyevalNixshouldn't break, if oneevaluation (e.g. the values that contain a package set by default) to
return additional information like a description.
With the change
nixos-option boot.kernelPackagesdelivers thefollowing output for me:
Things done
sandboxinnix.confon non-NixOS)nix-shell -p nox --run "nox-review wip"./result/bin/)nix path-info -Sbefore and after)