Fix Buildkite CI (input-output-hk#47)

Resolved input-output-hk#47

Author: rvl

nix-tools/.buildkite/build.sh

@@ -1,5 +1,5 @@
 #! /usr/bin/env nix-shell
-#! nix-shell --pure -i bash -p nix cabal-install ghc nix-prefetch-scripts
+#! nix-shell -I "nixpkgs=channel:nixos-19.03" --pure -i bash -p nix cabal-install ghc nix-prefetch-scripts git
 
 export NIX_PATH="nixpkgs=channel:nixos-19.03"
 
@@ -10,7 +10,7 @@ set -euo pipefail
 rm -f .nix-tools.cache
 
 echo "+++ Cabal configure"
-cabal new-update
+cabal new-update hackage.haskell.org,2019-03-15T00:00:00Z
 cabal new-configure
 
 echo
@@ -29,6 +29,10 @@ echo "There are no tests -- https://github.com/input-output-hk/haskell.nix/issue
 echo
 echo "+++ Run plan-to-nix again"
 
+# This file can interfere with the build.
+# https://github.com/input-output-hk/haskell.nix/issues/57
+rm -f .nix-tools.cache
+
 nix build -f nix1 nix-tools.components.exes.plan-to-nix
 ./result/bin/plan-to-nix --output nix2 --plan-json dist-newstyle/cache/plan.json
 

nix-tools/README.org

@@ -2,6 +2,8 @@
 
 * ~nix-tools~
 
+[[https://buildkite.com/input-output-hk/nix-tools][https://badge.buildkite.com/8c5ed154c28db5d7184560c8000e57180b2b362b7a0431602e.svg]]
+
 ~nix-tools~ is a set of Haskell → Nix tools to integrate Haskell
 projects into Nix build environments.
 
@@ -42,3 +44,6 @@ umbrella there are a few [[https://github.com/input-output-hk/haskell.nix/projec
 for tracking completion of the project goals. If you would like to
 follow or contribute to this effort then that would be a good place to
 start.
+
+Please open bug reports in the
+[[https://github.com/input-output-hk/haskell.nix/issues][Haskell.nix issue tracker]].