Save a warmed R package cache for faster installs in failing Actions

setup-r-dependencies/README.md

@@ -14,7 +14,8 @@ This action install dependencies for the current R environment based on the DESC
 Inputs available
 
 - `cache` - default `true`. Whether packages should be cached across runs or
-  not.
+  not. If `"always"` is provided, the package cache will be saved even if the
+  workflow fails.
 - `cache-version` - default `1`. If you need to invalidate the existing
   cache pass any other number and a new cache will be used. Ignored if
   `cache: false`. Note that you can also [delete caches

setup-r-dependencies/action.yaml

@@ -3,7 +3,7 @@ description: 'Action to setup installation tools and install R dependencies'
 author: 'Jim Hester'
 inputs:
   cache:
-    description: 'A boolean value indicating whether packages should be cached from one to the other'
+    description: 'Whether packages should be cached across runs or not. If `"always"` is provided, the package cache will be saved even if the workflow fails.'
     required: true
     default: true
   cache-version:
@@ -127,15 +127,17 @@ runs:
         shell: Rscript {0}
         working-directory: ${{ inputs.working-directory }}
 
-      - name: Restore R package cache
-        if: inputs.cache == 'true'
+      - name: R package cache
+        if: inputs.cache != 'false'
         uses: actions/cache@v4
         with:
           path: |
             ${{ env.R_LIBS_USER }}/*
             !${{ env.R_LIBS_USER }}/pak
           key: ${{ format('{0}-{1}-{2}-{3}', steps.install.outputs.os-version, steps.install.outputs.r-version, inputs.cache-version, hashFiles(format('{0}/.github/pkg.lock', inputs.working-directory ))) }}
-          restore-keys: ${{ steps.install.outputs.os-version }}-${{ steps.install.outputs.r-version }}-${{inputs.cache-version }}-
+          restore-keys: ${{ format('{0}-{1}-{2}-', steps.install.outputs.os-version, steps.install.outputs.r-version, inputs.cache-version) }}
+          # Used to save package installation on troublesome Actions
+          save-always: ${{ inputs.cache == 'always' }}
 
       - name: Install dependencies
         run: |