style: ensure flake registry remains sorted (#50)

Additionally, ensure the latest contents of `flake-registry.json` are
used when running `ci.sh`. Without `--tarball-ttl 0`, old contents can
be reused across multiple runs. This shouldn't be an issue in CI, but
it's helpful when running `ci.sh` manually, during development.

ci.sh

@@ -1,7 +1,11 @@
 #!/usr/bin/env bash
-# Test that the flake-registry.json format is valid
+# Test that the flake-registry.json format is sorted & valid
 set -euo pipefail
 
 cd "$(dirname "$0")"
 
+# Ensure current flake-registry.json file is sorted.
+nix registry list --tarball-ttl 0 --flake-registry "$PWD/flake-registry.json" \
+  | grep -- '^global ' | LC_ALL=C sort -u -c
+
 nix run --flake-registry "$PWD/flake-registry.json" nixpkgs#hello

flake-registry.json

@@ -34,6 +34,17 @@
         "type": "github"
       }
     },
+    {
+      "from": {
+        "id": "bundlers",
+        "type": "indirect"
+      },
+      "to": {
+        "owner": "NixOS",
+        "repo": "bundlers",
+        "type": "github"
+      }
+    },
     {
       "from": {
         "id": "cachix",
@@ -146,12 +157,12 @@
     },
     {
       "from": {
-        "id": "hercules-ci-effects",
+        "id": "helix",
         "type": "indirect"
       },
       "to": {
-        "owner": "hercules-ci",
+        "owner": "helix-editor",
-        "repo": "hercules-ci-effects",
+        "repo": "helix",
         "type": "github"
       }
     },
@@ -166,6 +177,17 @@
         "type": "github"
       }
     },
+    {
+      "from": {
+        "id": "hercules-ci-effects",
+        "type": "indirect"
+      },
+      "to": {
+        "owner": "hercules-ci",
+        "repo": "hercules-ci-effects",
+        "type": "github"
+      }
+    },
     {
       "from": {
         "id": "home-manager",
@@ -199,6 +221,17 @@
         "type": "github"
       }
     },
+    {
+      "from": {
+        "id": "nickel",
+        "type": "indirect"
+      },
+      "to": {
+        "owner": "tweag",
+        "repo": "nickel",
+        "type": "github"
+      }
+    },
     {
       "from": {
         "id": "nimble",
@@ -232,6 +265,17 @@
         "type": "github"
       }
     },
+    {
+      "from": {
+        "id": "nix-serve",
+        "type": "indirect"
+      },
+      "to": {
+        "owner": "edolstra",
+        "repo": "nix-serve",
+        "type": "github"
+      }
+    },
     {
       "from": {
         "id": "nixops",
@@ -276,17 +320,6 @@
         "type": "github"
       }
     },
-    {
-      "from": {
-        "id": "nur",
-        "type": "indirect"
-      },
-      "to": {
-        "owner": "nix-community",
-        "repo": "NUR",
-        "type": "github"
-      }
-    },
     {
       "from": {
         "id": "nixpkgs",
@@ -301,12 +334,12 @@
     },
     {
       "from": {
-        "id": "templates",
+        "id": "nur",
         "type": "indirect"
       },
       "to": {
-        "owner": "NixOS",
+        "owner": "nix-community",
-        "repo": "templates",
+        "repo": "NUR",
         "type": "github"
       }
     },
@@ -332,39 +365,6 @@
         "type": "github"
       }
     },
-    {
-      "from": {
-        "id": "nix-serve",
-        "type": "indirect"
-      },
-      "to": {
-        "owner": "edolstra",
-        "repo": "nix-serve",
-        "type": "github"
-      }
-    },
-    {
-      "from": {
-        "id": "nickel",
-        "type": "indirect"
-      },
-      "to": {
-        "owner": "tweag",
-        "repo": "nickel",
-        "type": "github"
-      }
-    },
-    {
-      "from": {
-        "id": "bundlers",
-        "type": "indirect"
-      },
-      "to": {
-        "owner": "NixOS",
-        "repo": "bundlers",
-        "type": "github"
-      }
-    },
     {
       "from": {
         "id": "pridefetch",
@@ -376,6 +376,17 @@
         "type": "github"
       }
     },
+    {
+      "from": {
+        "id": "sops-nix",
+        "type": "indirect"
+      },
+      "to": {
+        "owner": "Mic92",
+        "repo": "sops-nix",
+        "type": "github"
+      }
+    },
     {
       "from": {
         "id": "systems",
@@ -389,23 +400,12 @@
     },
     {
       "from": {
-        "id": "helix",
+        "id": "templates",
         "type": "indirect"
       },
       "to": {
-        "owner": "helix-editor",
+        "owner": "NixOS",
-        "repo": "helix",
+        "repo": "templates",
-        "type": "github"
-      }
-    },
-    {
-      "from": {
-        "id": "sops-nix",
-        "type": "indirect"
-      },
-      "to": {
-        "owner": "Mic92",
-        "repo": "sops-nix",
         "type": "github"
       }
     }