Add inputs.cache-save-always

Adds an input that borrows the `save-always` input from [v4 of `actions/cache`][0], which will run the post step to save the cache even if a failure occurs. Using the added `cache-save-always` input saves the cache when a build fails, which will speed up subsequent runs which restore the partial build. This comes at the cost of requiring a build when there is an exact `key` match, since the cache from a failed build will have the same `key` as a completed build.

[0]: https://github.com/actions/cache/tree/main#v4

action.yml

@@ -28,6 +28,9 @@ inputs:
   cache-prefix:
     required: true
     default: ""
+  cache-save-always:
+    description: "Save the dependencies and build cache even if a build fails"
+    default: false
 outputs:
   compiler:
     description: "compiler.actual value from stack query"
@@ -194,7 +197,6 @@ runs:
         done
 
     - name: Restore dependencies cache
-      id: restore-deps
       uses: actions/cache/restore@v3
       with:
         path: |
@@ -207,7 +209,6 @@ runs:
           ${{ inputs.cache-prefix }}${{ runner.os }}-stack-deps-${{ steps.stack-query.outputs.compiler }}-
 
     - name: Dependencies
-      if: steps.restore-deps.outputs.cache-hit != 'true'
       shell: bash
       working-directory: ${{ inputs.working-directory }}
       run: |
@@ -220,7 +221,7 @@ runs:
           ${{ inputs.stack-arguments }}
 
     - name: Save dependencies cache
-      if: steps.restore-deps.outputs.cache-hit != 'true'
+      if: success() || (failure() && inputs.cache-save-always)
       uses: actions/cache/save@v3
       with:
         path: |
@@ -230,7 +231,6 @@ runs:
         key: ${{ inputs.cache-prefix }}${{ runner.os }}-stack-deps-${{ steps.stack-query.outputs.compiler }}-${{ steps.setup.outputs.snapshot-hash }}-${{ steps.setup.outputs.package-hash }}
 
     - name: Restore build cache
-      id: restore-build
       uses: actions/cache/restore@v3
       with:
         path: ${{ steps.setup.outputs.stack-works }}
@@ -240,7 +240,6 @@ runs:
           ${{ inputs.cache-prefix }}${{ runner.os }}-stack-build-${{ steps.setup.outputs.snapshot-hash }}-
 
     - name: Build
-      if: steps.restore-build.outputs.cache-hit != 'true'
       shell: bash
       working-directory: ${{ inputs.working-directory }}
       run: |
@@ -251,7 +250,7 @@ runs:
           ${{ inputs.stack-arguments }}
 
     - name: Save build cache
-      if: steps.restore-build.outputs.cache-hit != 'true'
+      if: success() || (failure() && inputs.cache-save-always)
       uses: actions/cache/save@v3
       with:
         path: ${{ steps.setup.outputs.stack-works }}