Output path comparison

nix-env failed:
error: while evaluating anonymous function at /var/lib/ofborg/checkout/repo/38dca4e3aa6bca43ea96d2fcc04e8229/mr-est/eval-2-shlevy.ewr1.nix.ci/.gc-of-borg-outpaths.nix:44:12, called from undefined position:
while evaluating anonymous function at /var/lib/ofborg/checkout/repo/38dca4e3aa6bca43ea96d2fcc04e8229/mr-est/eval-2-shlevy.ewr1.nix.ci/pkgs/top-level/release-lib.nix:121:6, called from /var/lib/ofborg/checkout/repo/38dca4e3aa6bca43ea96d2fcc04e8229/mr-est/eval-2-shlevy.ewr1.nix.ci/lib/attrsets.nix:292:43:
while evaluating 'hydraJob' at /var/lib/ofborg/checkout/repo/38dca4e3aa6bca43ea96d2fcc04e8229/mr-est/eval-2-shlevy.ewr1.nix.ci/lib/customisation.nix:157:14, called from /var/lib/ofborg/checkout/repo/38dca4e3aa6bca43ea96d2fcc04e8229/mr-est/eval-2-shlevy.ewr1.nix.ci/pkgs/top-level/release-lib.nix:121:14:
while evaluating the attribute 'drvPath' at /var/lib/ofborg/checkout/repo/38dca4e3aa6bca43ea96d2fcc04e8229/mr-est/eval-2-shlevy.ewr1.nix.ci/lib/customisation.nix:174:13:
while evaluating the attribute 'drvPath' at /var/lib/ofborg/checkout/repo/38dca4e3aa6bca43ea96d2fcc04e8229/mr-est/eval-2-shlevy.ewr1.nix.ci/lib/customisation.nix:141:13:
while evaluating the attribute 'agdaWithArgs' of the derivation 'Agda-Sheaves-8a06162a8f0f7df308458db91d720cf8f7345d69' at /var/lib/ofborg/checkout/repo/38dca4e3aa6bca43ea96d2fcc04e8229/mr-est/eval-2-shlevy.ewr1.nix.ci/pkgs/development/libraries/agda/Agda-Sheaves/default.nix:5:3:
while evaluating the attribute 'nativeBuildInputs' of the derivation 'Agda-2.6.0.1' at /var/lib/ofborg/checkout/repo/38dca4e3aa6bca43ea96d2fcc04e8229/mr-est/eval-2-shlevy.ewr1.nix.ci/pkgs/development/haskell-modules/generic-builder.nix:245:3:
while evaluating the attribute 'buildInputs' of the derivation 'emacs-26.2' at /var/lib/ofborg/checkout/repo/38dca4e3aa6bca43ea96d2fcc04e8229/mr-est/eval-2-shlevy.ewr1.nix.ci/pkgs/applications/editors/emacs/default.nix:33:3:
while evaluating the attribute 'propagatedBuildInputs' of the derivation 'xlibs-wrapper' at /var/lib/ofborg/checkout/repo/38dca4e3aa6bca43ea96d2fcc04e8229/mr-est/eval-2-shlevy.ewr1.nix.ci/pkgs/development/libraries/xlibs-wrapper/default.nix:4:3:
while evaluating the attribute 'configureFlags' of the derivation 'fontconfig-2.12.6' at /var/lib/ofborg/checkout/repo/38dca4e3aa6bca43ea96d2fcc04e8229/mr-est/eval-2-shlevy.ewr1.nix.ci/pkgs/stdenv/generic/make-derivation.nix:191:11:
while evaluating the attribute 'buildCommand' of the derivation 'dejavu-fonts-minimal-2.37' at /var/lib/ofborg/checkout/repo/38dca4e3aa6bca43ea96d2fcc04e8229/mr-est/eval-2-shlevy.ewr1.nix.ci/pkgs/stdenv/generic/make-derivation.nix:191:11:
while evaluating the attribute 'nativeBuildInputs' of the derivation 'dejavu-fonts-full-2.37' at /var/lib/ofborg/checkout/repo/38dca4e3aa6bca43ea96d2fcc04e8229/mr-est/eval-2-shlevy.ewr1.nix.ci/pkgs/stdenv/generic/make-derivation.nix:191:11:
while evaluating the attribute 'preConfigure' of the derivation 'fontforge-20190413' at /var/lib/ofborg/checkout/repo/38dca4e3aa6bca43ea96d2fcc04e8229/mr-est/eval-2-shlevy.ewr1.nix.ci/pkgs/stdenv/generic/make-derivation.nix:191:11:
while evaluating the attribute 'src' of the derivation 'gnulib-20190326' at /var/lib/ofborg/checkout/repo/38dca4e3aa6bca43ea96d2fcc04e8229/mr-est/eval-2-shlevy.ewr1.nix.ci/pkgs/stdenv/generic/make-derivation.nix:191:11:
while evaluating the attribute 'nativeBuildInputs' of the derivation 'gnulib-a18f7ce' at /var/lib/ofborg/checkout/repo/38dca4e3aa6bca43ea96d2fcc04e8229/mr-est/eval-2-shlevy.ewr1.nix.ci/pkgs/build-support/fetchgit/default.nix:53:10:
while evaluating the attribute 'postPatch' of the derivation 'git-2.22.1' at /var/lib/ofborg/checkout/repo/38dca4e3aa6bca43ea96d2fcc04e8229/mr-est/eval-2-shlevy.ewr1.nix.ci/pkgs/stdenv/generic/make-derivation.nix:191:11:
while evaluating the attribute 'src' of the derivation 'openssh-8.0p1' at /var/lib/ofborg/checkout/repo/38dca4e3aa6bca43ea96d2fcc04e8229/mr-est/eval-2-shlevy.ewr1.nix.ci/pkgs/stdenv/generic/make-derivation.nix:191:11:
while evaluating the derivation attribute 'name' at /var/lib/ofborg/checkout/repo/38dca4e3aa6bca43ea96d2fcc04e8229/mr-est/eval-2-shlevy.ewr1.nix.ci/pkgs/build-support/fetchurl/default.nix:119:3:
undefined variable 'name' at /var/lib/ofborg/checkout/repo/38dca4e3aa6bca43ea96d2fcc04e8229/mr-est/eval-2-shlevy.ewr1.nix.ci/pkgs/tools/networking/openssh/default.nix:34:52