Avoid corrupting existing cloned Julia registries (#102)

* Reproduce add-julia-registry issue

* Skip registries restore when already present

* Expand ~

* Refactor paths step to use bash array

.github/workflows/CI.yml

@@ -214,3 +214,54 @@ jobs:
         logs_dir = joinpath(first(DEPOT_PATH), "logs")
         @assert !isempty(readdir(logs_dir))
 
+  test-save-cloned-registry:
+    needs: [generate-key]
+    runs-on: ubuntu-latest
+    outputs:
+      cache-name: ${{ steps.cache-name.outputs.cache-name }}
+    steps:
+    - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11
+    - name: Set cache-name
+      id: cache-name
+      run: |
+        echo "cache-name=${{ needs.generate-key.outputs.cache-name }}-${{ github.job }}" >>"$GITHUB_OUTPUT"
+    - name: Save cache
+      uses: ./
+      with:
+        cache-name: ${{ steps.cache-name.outputs.cache-name }}
+        # Cannot require a successful cache delete on forked PRs as the permissions for actions is limited to read
+        delete-old-caches: ${{ github.event.pull_request.head.repo.fork && 'false' || 'required' }}
+    - name: Add General registry clone
+      shell: julia --color=yes {0}
+      run: |
+        using Pkg
+        Pkg.Registry.add("General")
+      env:
+        JULIA_PKG_SERVER: ""
+    # Set the registry worktree to an older state to simulate the cache storing an old version of the registry.
+    - name: Use outdated General worktree
+      run: git -C ~/.julia/registries/General reset --hard HEAD~20
+
+  test-restore-cloned-registry:
+    needs: [test-save-cloned-registry]
+    runs-on: ubuntu-latest
+    steps:
+    - uses: actions/checkout@b4ffde65f46336ab88eb53be808477a3936bae11
+    - name: Add General registry clone
+      shell: julia --color=yes {0}
+      run: |
+        using Pkg
+        Pkg.Registry.add("General")
+      env:
+        JULIA_PKG_SERVER: ""
+    - name: Restore cache
+      uses: ./
+      with:
+        cache-name: ${{ needs.test-save-cloned-registry.outputs.cache-name }}
+        # Cannot require a successful cache delete on forked PRs as the permissions for actions is limited to read
+        delete-old-caches: ${{ github.event.pull_request.head.repo.fork && 'false' || 'required' }}
+    - name: Test registry is not corrupt
+      shell: julia --color=yes {0}
+      run: |
+        using Pkg
+        Pkg.Registry.update()

action.yml

@@ -69,19 +69,32 @@ runs:
         else
             depot="~/.julia"
         fi
-        echo "depot=$depot" >> $GITHUB_OUTPUT
-        [ "${{ inputs.cache-artifacts }}" = "true" ] && A_PATH="${depot}/artifacts"
-        echo "artifacts-path=$A_PATH" >> $GITHUB_OUTPUT
-        [ "${{ inputs.cache-packages }}" = "true" ] && P_PATH="${depot}/packages"
-        echo "packages-path=$P_PATH" >> $GITHUB_OUTPUT
-        [ "${{ inputs.cache-registries }}" = "true" ] && R_PATH="${depot}/registries"
-        echo "registries-path=$R_PATH" >> $GITHUB_OUTPUT
-        [ "${{ inputs.cache-compiled }}" = "true" ] && PCC_PATH="${depot}/compiled"
-        echo "compiled-path=$PCC_PATH" >> $GITHUB_OUTPUT
-        [ "${{ inputs.cache-scratchspaces }}" = "true" ] && S_PATH="${depot}/scratchspaces"
-        echo "scratchspaces-path=$S_PATH" >> $GITHUB_OUTPUT
-        [ "${{ inputs.cache-logs }}" = "true" ] && L_PATH="${depot}/logs"
-        echo "logs-path=$L_PATH" >> $GITHUB_OUTPUT
+        echo "depot=$depot" | tee -a "$GITHUB_OUTPUT"
+
+        cache_paths=()
+        artifacts_path="${depot}/artifacts"
+        [ "${{ inputs.cache-artifacts }}" = "true" ] && cache_paths+=("$artifacts_path")
+        packages_path="${depot}/packages"
+        [ "${{ inputs.cache-packages }}" = "true" ] && cache_paths+=("$packages_path")
+        registries_path="${depot}/registries"
+        if [ "${{ inputs.cache-registries }}" = "true" ]; then
+            if [ ! -d "${registries_path/#\~/$HOME}" ]; then
+                cache_paths+=("$registries_path")
+            else
+                echo "::warning::Julia depot registries already exist. Skipping restoring of cached registries to avoid potential merge conflicts when updating. Please ensure that \`julia-actions/cache\` preceeds any workflow steps which add registries."
+            fi
+        fi
+        compiled_path="${depot}/compiled"
+        [ "${{ inputs.cache-compiled }}" = "true" ] && cache_paths+=("$compiled_path")
+        scratchspaces_path="${depot}/scratchspaces"
+        [ "${{ inputs.cache-scratchspaces }}" = "true" ] && cache_paths+=("$scratchspaces_path")
+        logs_path="${depot}/logs"
+        [ "${{ inputs.cache-logs }}" = "true" ] && cache_paths+=("$logs_path")
+        {
+            echo "cache-paths<<EOF"
+            printf "%s\n" "${cache_paths[@]}"
+            echo "EOF"
+        } | tee -a "$GITHUB_OUTPUT"
       shell: bash
       env:
         PATH_DELIMITER: ${{ runner.OS == 'Windows' && ';' || ':' }}
@@ -109,13 +122,7 @@ runs:
       id: cache
       with:
         path: |
-          ${{ steps.paths.outputs.artifacts-path }}
-          ${{ steps.paths.outputs.packages-path }}
-          ${{ steps.paths.outputs.registries-path }}
-          ${{ steps.paths.outputs.scratchspaces-path }}
-          ${{ steps.paths.outputs.compiled-path }}
-          ${{ steps.paths.outputs.logs-path }}
-
+          ${{ steps.paths.outputs.cache-paths }}
         key: ${{ steps.keys.outputs.key }}
         restore-keys: ${{ steps.keys.outputs.restore-key }}
         enableCrossOsArchive: false