treewide: refactor `.attrs.sh` detection

When specifying the `builder` attribute in `stdenv.mkDerivation`, this
will be effectively transformed into

    builtins.derivation {
      builder = stdenv.shell;
      args = [ "-e" builder ];
    }

This also means that `default-builder.sh` is never sourced and as a
result it's not guaranteed that `$NIX_ATTRS_SH_FILE` is set to a correct
location[1].

Also, we need to source `.attrs.sh` to source `$stdenv`. So, the
following is done now:

* If `$NIX_ATTRS_SH_FILE` points to a correct location, then use it.
  Directly using `.attrs.sh` is problematic for `nix-shell(1)` usage
  (see previous commit for more context), so prefer the environment
  variable if possible.

* Otherwise, if `.attrs.sh` exists, then use it. See [1] for when this
  can happen.

* If neither applies, it can be assumed that `__structuredAttrs` is
  turned off and thus nothing needs to be done.

[1] It's possible that it doesn't exist at all - in case of Nix 2.3 or
    it can point to a wrong location on older Nix versions with a bug in
    `__structuredAttrs`.

34 files changed, 34 insertions, 36 deletions

diff --git a/pkgs/applications/misc/adobe-reader/builder.sh b/pkgs/applications/misc/adobe-reader/builder.sh
index 6047c0826430..4291da80576d 100644
--- a/pkgs/applications/misc/adobe-reader/builder.sh
+++ b/pkgs/applications/misc/adobe-reader/builder.sh
@@ -1,4 +1,4 @@
-if [ -e .attrs.sh ]; then source .attrs.sh; fi
+if [ -e "$NIX_ATTRS_SH_FILE" ]; then . "$NIX_ATTRS_SH_FILE"; elif [ -f .attrs.sh ]; then . .attrs.sh; fi
 source $stdenv/setup
 
 echo "unpacking $src..."
diff --git a/pkgs/build-support/fetchbzr/builder.sh b/pkgs/build-support/fetchbzr/builder.sh
index 991864719a07..4515e0e82f49 100644
--- a/pkgs/build-support/fetchbzr/builder.sh
+++ b/pkgs/build-support/fetchbzr/builder.sh
@@ -1,4 +1,4 @@
-if [ -e .attrs.sh ]; then source .attrs.sh; fi
+if [ -e "$NIX_ATTRS_SH_FILE" ]; then . "$NIX_ATTRS_SH_FILE"; elif [ -f .attrs.sh ]; then . .attrs.sh; fi
 source "$stdenv/setup"
 
 echo "exporting \`$url' (revision $rev) into \`$out'"
diff --git a/pkgs/build-support/fetchcvs/builder.sh b/pkgs/build-support/fetchcvs/builder.sh
index 4b49e9676ec0..7e4dde4a64c8 100644
--- a/pkgs/build-support/fetchcvs/builder.sh
+++ b/pkgs/build-support/fetchcvs/builder.sh
@@ -1,4 +1,4 @@
-if [ -e .attrs.sh ]; then source .attrs.sh; fi
+if [ -e "$NIX_ATTRS_SH_FILE" ]; then . "$NIX_ATTRS_SH_FILE"; elif [ -f .attrs.sh ]; then . .attrs.sh; fi
 source $stdenv/setup
 
 (echo "#!$SHELL"; \
diff --git a/pkgs/build-support/fetchdarcs/builder.sh b/pkgs/build-support/fetchdarcs/builder.sh
index 75b9066dba6f..39838db255a6 100644
--- a/pkgs/build-support/fetchdarcs/builder.sh
+++ b/pkgs/build-support/fetchdarcs/builder.sh
@@ -1,4 +1,4 @@
-if [ -e .attrs.sh ]; then source .attrs.sh; fi
+if [ -e "$NIX_ATTRS_SH_FILE" ]; then . "$NIX_ATTRS_SH_FILE"; elif [ -f .attrs.sh ]; then . .attrs.sh; fi
 source $stdenv/setup
 
 tagtext=""
diff --git a/pkgs/build-support/fetchdocker/fetchdocker-builder.sh b/pkgs/build-support/fetchdocker/fetchdocker-builder.sh
index 4eb70f672d48..489914a2a8b4 100644
--- a/pkgs/build-support/fetchdocker/fetchdocker-builder.sh
+++ b/pkgs/build-support/fetchdocker/fetchdocker-builder.sh
@@ -1,4 +1,4 @@
-if [ -e .attrs.sh ]; then source .attrs.sh; fi
+if [ -e "$NIX_ATTRS_SH_FILE" ]; then . "$NIX_ATTRS_SH_FILE"; elif [ -f .attrs.sh ]; then . .attrs.sh; fi
 source "${stdenv}/setup"
 echo "exporting ${repository}/${imageName} (tag: ${tag}) into ${out}"
 mkdir -p "${out}"
diff --git a/pkgs/build-support/fetchfossil/builder.sh b/pkgs/build-support/fetchfossil/builder.sh
index 36b758ab574e..fe828d0ada9d 100644
--- a/pkgs/build-support/fetchfossil/builder.sh
+++ b/pkgs/build-support/fetchfossil/builder.sh
@@ -1,4 +1,4 @@
-if [ -e .attrs.sh ]; then source .attrs.sh; fi
+if [ -e "$NIX_ATTRS_SH_FILE" ]; then . "$NIX_ATTRS_SH_FILE"; elif [ -f .attrs.sh ]; then . .attrs.sh; fi
 source $stdenv/setup
 echo "Cloning Fossil $url [$rev] into $out"
 
diff --git a/pkgs/build-support/fetchgit/builder.sh b/pkgs/build-support/fetchgit/builder.sh
index 77f6381b09ab..95176beea8c1 100644
--- a/pkgs/build-support/fetchgit/builder.sh
+++ b/pkgs/build-support/fetchgit/builder.sh
@@ -3,7 +3,7 @@
 # - revision specified and remote has a HEAD
 # - revision specified and remote without HEAD
 #
-if [ -e .attrs.sh ]; then source .attrs.sh; fi
+if [ -e "$NIX_ATTRS_SH_FILE" ]; then . "$NIX_ATTRS_SH_FILE"; elif [ -f .attrs.sh ]; then . .attrs.sh; fi
 source $stdenv/setup
 
 echo "exporting $url (rev $rev) into $out"
diff --git a/pkgs/build-support/fetchhg/builder.sh b/pkgs/build-support/fetchhg/builder.sh
index 1ce294757713..20dfde4b10d4 100644
--- a/pkgs/build-support/fetchhg/builder.sh
+++ b/pkgs/build-support/fetchhg/builder.sh
@@ -1,4 +1,4 @@
-if [ -e .attrs.sh ]; then source .attrs.sh; fi
+if [ -e "$NIX_ATTRS_SH_FILE" ]; then . "$NIX_ATTRS_SH_FILE"; elif [ -f .attrs.sh ]; then . .attrs.sh; fi
 source $stdenv/setup
 echo "getting $url${rev:+ ($rev)} into $out"
 
diff --git a/pkgs/build-support/fetchipfs/builder.sh b/pkgs/build-support/fetchipfs/builder.sh
index ca77962b5384..1ddd111b1518 100644
--- a/pkgs/build-support/fetchipfs/builder.sh
+++ b/pkgs/build-support/fetchipfs/builder.sh
@@ -1,4 +1,4 @@
-if [ -e .attrs.sh ]; then source .attrs.sh; fi
+if [ -e "$NIX_ATTRS_SH_FILE" ]; then . "$NIX_ATTRS_SH_FILE"; elif [ -f .attrs.sh ]; then . .attrs.sh; fi
 source $stdenv/setup
 
 # Curl flags to handle redirects, not use EPSV, handle cookies for
diff --git a/pkgs/build-support/fetchmtn/builder.sh b/pkgs/build-support/fetchmtn/builder.sh
index 1aabd7949ee1..de929fad55a9 100644
--- a/pkgs/build-support/fetchmtn/builder.sh
+++ b/pkgs/build-support/fetchmtn/builder.sh
@@ -1,4 +1,4 @@
-if [ -e .attrs.sh ]; then source .attrs.sh; fi
+if [ -e "$NIX_ATTRS_SH_FILE" ]; then . "$NIX_ATTRS_SH_FILE"; elif [ -f .attrs.sh ]; then . .attrs.sh; fi
 source $stdenv/setup
 
 set -x
diff --git a/pkgs/build-support/fetchsvn/builder.sh b/pkgs/build-support/fetchsvn/builder.sh
index aa4d049aba43..e187747f14e6 100644
--- a/pkgs/build-support/fetchsvn/builder.sh
+++ b/pkgs/build-support/fetchsvn/builder.sh
@@ -1,4 +1,4 @@
-if [ -e .attrs.sh ]; then source .attrs.sh; fi
+if [ -e "$NIX_ATTRS_SH_FILE" ]; then . "$NIX_ATTRS_SH_FILE"; elif [ -f .attrs.sh ]; then . .attrs.sh; fi
 source $stdenv/setup
 
 echo "exporting $url (r$rev) into $out"
diff --git a/pkgs/build-support/fetchsvnssh/builder.sh b/pkgs/build-support/fetchsvnssh/builder.sh
index 5782151524f7..e553446346de 100644
--- a/pkgs/build-support/fetchsvnssh/builder.sh
+++ b/pkgs/build-support/fetchsvnssh/builder.sh
@@ -1,4 +1,4 @@
-if [ -e .attrs.sh ]; then source .attrs.sh; fi
+if [ -e "$NIX_ATTRS_SH_FILE" ]; then . "$NIX_ATTRS_SH_FILE"; elif [ -f .attrs.sh ]; then . .attrs.sh; fi
 source $stdenv/setup
 
 echo "exporting $url (r$rev) into $out"
diff --git a/pkgs/build-support/fetchurl/builder.sh b/pkgs/build-support/fetchurl/builder.sh
index e8eaba934858..a82728ef1025 100644
--- a/pkgs/build-support/fetchurl/builder.sh
+++ b/pkgs/build-support/fetchurl/builder.sh
@@ -1,4 +1,4 @@
-if [ -e .attrs.sh ]; then source .attrs.sh; fi
+if [ -e "$NIX_ATTRS_SH_FILE" ]; then . "$NIX_ATTRS_SH_FILE"; elif [ -f .attrs.sh ]; then . .attrs.sh; fi
 source $stdenv/setup
 
 source $mirrorsFile
diff --git a/pkgs/desktops/gnustep/make/builder.sh b/pkgs/desktops/gnustep/make/builder.sh
index 736635ab5026..79ead3f7b729 100644
--- a/pkgs/desktops/gnustep/make/builder.sh
+++ b/pkgs/desktops/gnustep/make/builder.sh
@@ -1,4 +1,4 @@
-if [ -e .attrs.sh ]; then source .attrs.sh; fi
+if [ -e "$NIX_ATTRS_SH_FILE" ]; then . "$NIX_ATTRS_SH_FILE"; elif [ -f .attrs.sh ]; then . .attrs.sh; fi
 source $stdenv/setup
 
 providedPreConfigure="$preConfigure";
diff --git a/pkgs/development/compilers/aspectj/builder.sh b/pkgs/development/compilers/aspectj/builder.sh
index 7ea0a40d3748..31ec97942e52 100755
--- a/pkgs/development/compilers/aspectj/builder.sh
+++ b/pkgs/development/compilers/aspectj/builder.sh
@@ -1,4 +1,4 @@
-if [ -e .attrs.sh ]; then source .attrs.sh; fi
+if [ -e "$NIX_ATTRS_SH_FILE" ]; then . "$NIX_ATTRS_SH_FILE"; elif [ -f .attrs.sh ]; then . .attrs.sh; fi
 source $stdenv/setup
 
 export JAVA_HOME=$jre
diff --git a/pkgs/development/compilers/chicken/4/fetchegg/builder.sh b/pkgs/development/compilers/chicken/4/fetchegg/builder.sh
index cb56eabc5d78..78535382a7ca 100644
--- a/pkgs/development/compilers/chicken/4/fetchegg/builder.sh
+++ b/pkgs/development/compilers/chicken/4/fetchegg/builder.sh
@@ -1,4 +1,4 @@
-if [ -e .attrs.sh ]; then source .attrs.sh; fi
+if [ -e "$NIX_ATTRS_SH_FILE" ]; then . "$NIX_ATTRS_SH_FILE"; elif [ -f .attrs.sh ]; then . .attrs.sh; fi
 source $stdenv/setup
 
 echo "exporting egg ${eggName} (version $version) into $out"
diff --git a/pkgs/development/compilers/fpc/binary-builder-darwin.sh b/pkgs/development/compilers/fpc/binary-builder-darwin.sh
index 39db0518281d..8a8600f1f639 100755
--- a/pkgs/development/compilers/fpc/binary-builder-darwin.sh
+++ b/pkgs/development/compilers/fpc/binary-builder-darwin.sh
@@ -1,4 +1,4 @@
-if [ -e .attrs.sh ]; then source .attrs.sh; fi
+if [ -e "$NIX_ATTRS_SH_FILE" ]; then . "$NIX_ATTRS_SH_FILE"; elif [ -f .attrs.sh ]; then . .attrs.sh; fi
 source $stdenv/setup
 
 pkgdir=$(pwd)/pkg
diff --git a/pkgs/development/compilers/fpc/binary-builder.sh b/pkgs/development/compilers/fpc/binary-builder.sh
index c471378c275f..568c3094107a 100755
--- a/pkgs/development/compilers/fpc/binary-builder.sh
+++ b/pkgs/development/compilers/fpc/binary-builder.sh
@@ -1,4 +1,4 @@
-if [ -e .attrs.sh ]; then source .attrs.sh; fi
+if [ -e "$NIX_ATTRS_SH_FILE" ]; then . "$NIX_ATTRS_SH_FILE"; elif [ -f .attrs.sh ]; then . .attrs.sh; fi
 source $stdenv/setup
 
 tar xf $src
diff --git a/pkgs/development/compilers/ios-cross-compile/9.2_builder.sh b/pkgs/development/compilers/ios-cross-compile/9.2_builder.sh
index 47459664af0a..4eef8acb0693 100644
--- a/pkgs/development/compilers/ios-cross-compile/9.2_builder.sh
+++ b/pkgs/development/compilers/ios-cross-compile/9.2_builder.sh
@@ -1,5 +1,5 @@
 # -*- shell-script -*-
-if [ -e .attrs.sh ]; then source .attrs.sh; fi
+if [ -e "$NIX_ATTRS_SH_FILE" ]; then . "$NIX_ATTRS_SH_FILE"; elif [ -f .attrs.sh ]; then . .attrs.sh; fi
 source $stdenv/setup
 
 function extract
diff --git a/pkgs/development/compilers/ocaml/builder.sh b/pkgs/development/compilers/ocaml/builder.sh
index 88acc0654cf2..85b26848f4e4 100644
--- a/pkgs/development/compilers/ocaml/builder.sh
+++ b/pkgs/development/compilers/ocaml/builder.sh
@@ -1,4 +1,4 @@
-if [ -e .attrs.sh ]; then source .attrs.sh; fi
+if [ -e "$NIX_ATTRS_SH_FILE" ]; then . "$NIX_ATTRS_SH_FILE"; elif [ -f .attrs.sh ]; then . .attrs.sh; fi
 source $stdenv/setup
 
 configureFlags="-prefix $out $configureFlags"
diff --git a/pkgs/development/libraries/glibc/locales-builder.sh b/pkgs/development/libraries/glibc/locales-builder.sh
index d91f936c937b..27894b09b91c 100644
--- a/pkgs/development/libraries/glibc/locales-builder.sh
+++ b/pkgs/development/libraries/glibc/locales-builder.sh
@@ -1,4 +1,4 @@
-if [ -e .attrs.sh ]; then source .attrs.sh; fi
+if [ -e "$NIX_ATTRS_SH_FILE" ]; then . "$NIX_ATTRS_SH_FILE"; elif [ -f .attrs.sh ]; then . .attrs.sh; fi
 # Glibc cannot have itself in its RPATH.
 export NIX_NO_SELF_RPATH=1
 
diff --git a/pkgs/development/libraries/gtk-sharp/builder.sh b/pkgs/development/libraries/gtk-sharp/builder.sh
index 73914495d6d4..45e640e2a708 100644
--- a/pkgs/development/libraries/gtk-sharp/builder.sh
+++ b/pkgs/development/libraries/gtk-sharp/builder.sh
@@ -1,4 +1,4 @@
-if [ -e .attrs.sh ]; then source .attrs.sh; fi
+if [ -e "$NIX_ATTRS_SH_FILE" ]; then . "$NIX_ATTRS_SH_FILE"; elif [ -f .attrs.sh ]; then . .attrs.sh; fi
 source $stdenv/setup
 
 genericBuild
diff --git a/pkgs/development/libraries/wtk/builder.sh b/pkgs/development/libraries/wtk/builder.sh
index c3ad173b0933..ca5157c6d71a 100644
--- a/pkgs/development/libraries/wtk/builder.sh
+++ b/pkgs/development/libraries/wtk/builder.sh
@@ -1,4 +1,4 @@
-if [ -e .attrs.sh ]; then source .attrs.sh; fi
+if [ -e "$NIX_ATTRS_SH_FILE" ]; then . "$NIX_ATTRS_SH_FILE"; elif [ -f .attrs.sh ]; then . .attrs.sh; fi
 source $stdenv/setup
 
 mkdir unzipped
diff --git a/pkgs/development/perl-modules/generic/builder.sh b/pkgs/development/perl-modules/generic/builder.sh
index 110094ad8a49..4da9f7a98212 100644
--- a/pkgs/development/perl-modules/generic/builder.sh
+++ b/pkgs/development/perl-modules/generic/builder.sh
@@ -1,4 +1,4 @@
-if [ -e .attrs.sh ]; then source .attrs.sh; fi
+if [ -e "$NIX_ATTRS_SH_FILE" ]; then . "$NIX_ATTRS_SH_FILE"; elif [ -f .attrs.sh ]; then . .attrs.sh; fi
 source $stdenv/setup
 
 PERL5LIB="$PERL5LIB${PERL5LIB:+:}$out/lib/perl5/site_perl"
diff --git a/pkgs/development/tools/build-managers/boot/builder.sh b/pkgs/development/tools/build-managers/boot/builder.sh
index e007cbac9582..4506e3f0f861 100644
--- a/pkgs/development/tools/build-managers/boot/builder.sh
+++ b/pkgs/development/tools/build-managers/boot/builder.sh
@@ -1,4 +1,4 @@
-if [ -e .attrs.sh ]; then source .attrs.sh; fi
+if [ -e "$NIX_ATTRS_SH_FILE" ]; then . "$NIX_ATTRS_SH_FILE"; elif [ -f .attrs.sh ]; then . .attrs.sh; fi
 source $stdenv/setup
 
 boot_bin=$out/bin/boot
diff --git a/pkgs/development/tools/misc/automake/builder.sh b/pkgs/development/tools/misc/automake/builder.sh
index 0cb1d5d61e33..b08e7251e9e2 100644
--- a/pkgs/development/tools/misc/automake/builder.sh
+++ b/pkgs/development/tools/misc/automake/builder.sh
@@ -1,4 +1,4 @@
-if [ -e .attrs.sh ]; then source .attrs.sh; fi
+if [ -e "$NIX_ATTRS_SH_FILE" ]; then . "$NIX_ATTRS_SH_FILE"; elif [ -f .attrs.sh ]; then . .attrs.sh; fi
 source $stdenv/setup
 
 # Wrap the given `aclocal' program, appending extra `-I' flags
diff --git a/pkgs/development/tools/parsing/antlr/builder.sh b/pkgs/development/tools/parsing/antlr/builder.sh
index 55259b932124..c1d20845e6bf 100644
--- a/pkgs/development/tools/parsing/antlr/builder.sh
+++ b/pkgs/development/tools/parsing/antlr/builder.sh
@@ -1,4 +1,4 @@
-if [ -e .attrs.sh ]; then source .attrs.sh; fi
+if [ -e "$NIX_ATTRS_SH_FILE" ]; then . "$NIX_ATTRS_SH_FILE"; elif [ -f .attrs.sh ]; then . .attrs.sh; fi
 source $stdenv/setup
 
 tar zxvf $src
diff --git a/pkgs/misc/cups/drivers/samsung/4.00.39/builder.sh b/pkgs/misc/cups/drivers/samsung/4.00.39/builder.sh
index bdb522744182..829bc6509e06 100644
--- a/pkgs/misc/cups/drivers/samsung/4.00.39/builder.sh
+++ b/pkgs/misc/cups/drivers/samsung/4.00.39/builder.sh
@@ -1,4 +1,4 @@
-if [ -e .attrs.sh ]; then source .attrs.sh; fi
+if [ -e "$NIX_ATTRS_SH_FILE" ]; then . "$NIX_ATTRS_SH_FILE"; elif [ -f .attrs.sh ]; then . .attrs.sh; fi
 source $stdenv/setup
 
 arch=$(uname -m)
diff --git a/pkgs/os-specific/linux/nvidia-x11/builder.sh b/pkgs/os-specific/linux/nvidia-x11/builder.sh
index b7824f209776..fbb116ab42ad 100755
--- a/pkgs/os-specific/linux/nvidia-x11/builder.sh
+++ b/pkgs/os-specific/linux/nvidia-x11/builder.sh
@@ -1,4 +1,4 @@
-if [ -e .attrs.sh ]; then source .attrs.sh; fi
+if [ -e "$NIX_ATTRS_SH_FILE" ]; then . "$NIX_ATTRS_SH_FILE"; elif [ -f .attrs.sh ]; then . .attrs.sh; fi
 source $stdenv/setup
 
 unpackManually() {
diff --git a/pkgs/os-specific/linux/opengl/xorg-sys/builder.sh b/pkgs/os-specific/linux/opengl/xorg-sys/builder.sh
index 34f9b1579455..ed2c60da2612 100644
--- a/pkgs/os-specific/linux/opengl/xorg-sys/builder.sh
+++ b/pkgs/os-specific/linux/opengl/xorg-sys/builder.sh
@@ -1,4 +1,4 @@
-if [ -e .attrs.sh ]; then source .attrs.sh; fi
+if [ -e "$NIX_ATTRS_SH_FILE" ]; then . "$NIX_ATTRS_SH_FILE"; elif [ -f .attrs.sh ]; then . .attrs.sh; fi
 source $stdenv/setup
 
 mkdir -p $out/lib
diff --git a/pkgs/servers/http/tomcat/axis2/builder.sh b/pkgs/servers/http/tomcat/axis2/builder.sh
index d334ab6f927f..de8e225456b4 100644
--- a/pkgs/servers/http/tomcat/axis2/builder.sh
+++ b/pkgs/servers/http/tomcat/axis2/builder.sh
@@ -1,4 +1,4 @@
-if [ -e .attrs.sh ]; then source .attrs.sh; fi
+if [ -e "$NIX_ATTRS_SH_FILE" ]; then . "$NIX_ATTRS_SH_FILE"; elif [ -f .attrs.sh ]; then . .attrs.sh; fi
 source $stdenv/setup
 
 unzip $src
diff --git a/pkgs/servers/x11/xorg/builder.sh b/pkgs/servers/x11/xorg/builder.sh
index a9c607ae35ea..833acf43a5b0 100644
--- a/pkgs/servers/x11/xorg/builder.sh
+++ b/pkgs/servers/x11/xorg/builder.sh
@@ -1,4 +1,4 @@
-if [ -e .attrs.sh ]; then source .attrs.sh; fi
+if [ -e "$NIX_ATTRS_SH_FILE" ]; then . "$NIX_ATTRS_SH_FILE"; elif [ -f .attrs.sh ]; then . .attrs.sh; fi
 # This is the builder for all X.org components.
 source $stdenv/setup
 
diff --git a/pkgs/stdenv/generic/default-builder.sh b/pkgs/stdenv/generic/default-builder.sh
index 8c6fec7873b6..d49fb8aa57fc 100644
--- a/pkgs/stdenv/generic/default-builder.sh
+++ b/pkgs/stdenv/generic/default-builder.sh
@@ -1,6 +1,4 @@
-if [ -f .attrs.sh ]; then
-    . .attrs.sh
-fi
+if [ -e "$NIX_ATTRS_SH_FILE" ]; then . "$NIX_ATTRS_SH_FILE"; elif [ -f .attrs.sh ]; then . .attrs.sh; fi
 
 source $stdenv/setup
 genericBuild
diff --git a/pkgs/test/simple/builder.sh b/pkgs/test/simple/builder.sh
index 908faec3c388..0b09a109bead 100644
--- a/pkgs/test/simple/builder.sh
+++ b/pkgs/test/simple/builder.sh
@@ -1,4 +1,4 @@
-if [ -e .attrs.sh ]; then source .attrs.sh; fi
+if [ -e "$NIX_ATTRS_SH_FILE" ]; then . "$NIX_ATTRS_SH_FILE"; elif [ -f .attrs.sh ]; then . .attrs.sh; fi
 set -x
 
 export NIX_DEBUG=1