build(ci): [Re]Add CABAL_CACHE_VERSION to the GitHub workflow

Author: sgillespie

.github/workflows/haskell.yml

@@ -25,6 +25,11 @@ jobs:
           - os: macos-latest
             compiler-nix-name: ghc96
 
+    env:
+      # Increment this value to "invalidate" the cabal cache. Be sure to do this
+      # after updating dependencies (Hackage or chap)
+      CABAL_CACHE_VERSION: 1
+
     steps:
       - name: Checkout code
         uses: actions/checkout@v3
@@ -48,8 +53,8 @@ jobs:
           path: |
             ~/.cabal-devx/packages
             ~/.cabal-devx/store
-          key: ${{ runner.os }}-${{ matrix.compiler-nix-name }}-${{ hashFiles('**/*.cabal', '**/cabal.project', '**/cabal.project.freeze') }}
-          restore-keys: ${{ runner.os }}-${{ matrix.compiler-nix-name }}-
+          key: ${{ env.CABAL_CACHE_VERSION }}-${{ runner.os }}-${{ matrix.compiler-nix-name }}-${{ hashFiles('**/*.cabal', '**/cabal.project', '**/cabal.project.freeze') }}
+          restore-keys: ${{ env.CABAL_CACHE_VERSION }}-${{ runner.os }}-${{ matrix.compiler-nix-name }}-
       - name: cabal update
         run: cabal update
       - name: cabal build dependencies

CONTRIBUTING.rst

@@ -177,6 +177,13 @@ If this fails to build, it may also be necessary to update haskell.nix::
 
   nix flake lock --update-input haskellNix
 
+Increment ``CABAL_CACHE_VERSION`` in ``.github/workflows/haskell.yml``::
+
+  env:
+    # Increment this value to "invalidate" the cabal cache. Be sure to do this
+    # after updating dependencies (Hackage or chap)
+    CABAL_CACHE_VERSION: 2
+
 From the Cardano Haskell Package repository
 -------------------------------------------
 
@@ -215,6 +222,13 @@ In rare cases, it may also be necessary to update haskell.nix::
 
   nix flake lock --update-input haskellNix
 
+Increment ``CABAL_CACHE_VERSION`` in ``.github/workflows/haskell.yml``::
+
+  env:
+    # Increment this value to "invalidate" the cabal cache. Be sure to do this
+    # after updating dependencies (Hackage or chap)
+    CABAL_CACHE_VERSION: 2
+
 Using unreleased versions of dependencies
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^