chore: remove snapshots

.github/workflows/copilot-setup-steps.yml

@@ -15,7 +15,6 @@ jobs:
   # The job MUST be called `copilot-setup-steps` or it will not be picked up by Copilot.
   copilot-setup-steps:
     runs-on: ubuntu-latest
-    snapshot: true
 
     permissions:
       contents: read

inst/templates/workflows/copilot-setup-steps.yml

@@ -15,7 +15,6 @@ jobs:
   # The job MUST be called `copilot-setup-steps` or it will not be picked up by Copilot.
   copilot-setup-steps:
     runs-on: ubuntu-latest
-    snapshot: true
 
     permissions:
       contents: read

inst/templates/workflows/install/action.yml

@@ -39,13 +39,29 @@ runs:
     - if: inputs.use-container != 'true'
       uses: r-lib/actions/setup-pandoc@v2
 
-    - if: inputs.use-container != 'true'
-      uses: r-lib/actions/setup-r@v2
+    # Always run setup-r, even in containers.  With install-r: false it
+    # skips the R download but still sets R_LIBS_USER, TZ, NOT_CRAN, etc.
+    # in GITHUB_ENV — the official way to align the environment for
+    # setup-r-dependencies and actions/cache.
+    - uses: r-lib/actions/setup-r@v2
       with:
+        install-r: ${{ inputs.use-container != 'true' }}
         r-version: ${{ inputs.r-version }}
         http-user-agent: ${{ inputs.http-user-agent }}
         use-public-rspm: true
 
+    # In pre-warmed containers every package may already be in the system
+    # library, so nothing is ever written to R_LIBS_USER.  Ensure the
+    # directory exists with a sentinel so the actions/cache glob matches
+    # and the "Path Validation Error" warning doesn't fire at cache-save.
+    - if: inputs.use-container == 'true'
+      name: Ensure R_LIBS_USER exists
+      shell: bash
+      run: |
+        lib="$(Rscript -e 'cat(Sys.getenv("R_LIBS_USER"))')"
+        mkdir -p "$lib"
+        touch "$lib/.keep"
+
     - uses: r-lib/actions/setup-r-dependencies@v2
       env:
         GITHUB_PAT: ${{ inputs.token }}