nix: Workaround for regenerate.sh error on buildkite

.buildkite/pipeline.yml

@@ -44,7 +44,9 @@ steps:
       system: x86_64-linux
 
   - label: 'Check auto-generated Nix'
-    command: './nix/regenerate.sh && nix-build ./nix -A iohkNix.checkStackProject -o check-stack-project.sh && ./check-stack-project.sh'
+    commands:
+      - './nix/regenerate.sh --cache /dev/null'
+      - 'nix-build ./nix -A iohkNix.checkStackProject -o check-stack-project.sh && ./check-stack-project.sh'
     agents:
       system: x86_64-linux
 

nix/regenerate.sh

@@ -2,4 +2,4 @@
 
 set -euo pipefail
 
-exec $(nix-build `dirname $0`/. -A stackNixRegenerate --no-out-link)
+exec $(nix-build `dirname $0`/. -A stackNixRegenerate --no-out-link) "$@"

nix/sources.json

@@ -12,15 +12,15 @@
         "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
     },
     "iohk-nix": {
-        "branch": "master",
+        "branch": "rvl/stack-nix-regenerate-fix",
         "description": "nix scripts shared across projects",
         "homepage": null,
         "owner": "input-output-hk",
         "repo": "iohk-nix",
-        "rev": "2e569616fd89a36f19e7cbc00fb35330787d8fdf",
-        "sha256": "0kxzdk6x36p2viap4hff8psz8mq7zpbnf1rd28n16n5kc63d20sy",
+        "rev": "086b3838282d75b1184280ea79f9ff681f8c28d0",
+        "sha256": "1xrfcba0c3zyqlphpmxj9kfq9mvgg8615l1809lhx0y4aa41b4c9",
         "type": "tarball",
-        "url": "https://github.com/input-output-hk/iohk-nix/archive/2e569616fd89a36f19e7cbc00fb35330787d8fdf.tar.gz",
+        "url": "https://github.com/input-output-hk/iohk-nix/archive/086b3838282d75b1184280ea79f9ff681f8c28d0.tar.gz",
         "url_template": "https://github.com/<owner>/<repo>/archive/<rev>.tar.gz"
     },
     "niv": {