debug: save then lookup same key to isolate backend issue

.gitea/actions/rust-cache/action.yml

@@ -27,33 +27,6 @@ runs:
         echo "hash=$HASH" >> $GITHUB_OUTPUT
         echo "fingerprint=$HASH" >> $GITHUB_ENV
 
-    - name: Lookup cache (debug)
-      id: cache-lookup
-      uses: https://gitea.com/actions/cache@v3
-      with:
-        path: ~/.cargo/registry
-        key: rust-linux-${{ steps.cache-key.outputs.hash }}
-        lookup-only: true
-
-    - name: Show lookup result
-      shell: bash
-      run: |
-        echo "cache-hit (lookup): ${{ steps.cache-lookup.outputs.cache-hit }}"
-        echo "key used: rust-linux-${{ steps.cache-key.outputs.hash }}"
-
-    - name: Cache cargo + rustup
-      id: cache
-      uses: https://gitea.com/actions/cache@v3
-      with:
-        path: |
-          ~/.cargo/registry
-          ~/.cargo/git
-          ~/.rustup/toolchains
-          ~/.rustup/settings.toml
-          target
-        key: rust-linux-${{ steps.cache-key.outputs.hash }}
-        restore-keys: rust-linux-
-
     - name: Setup Rust
       shell: bash
       run: |
@@ -63,9 +36,37 @@ runs:
         # Add cargo bin to PATH for subsequent steps
         echo "$HOME/.cargo/bin" >> $GITHUB_PATH
 
-    - name: Show cached sizes
+    - name: Show sizes before cache
       shell: bash
       run: |
         echo "=== ~/.cargo ===" && du -sh ~/.cargo 2>/dev/null || echo "(empty)"
         echo "=== ~/.rustup ===" && du -sh ~/.rustup 2>/dev/null || echo "(empty)"
-        echo "=== target ==="   && du -sh target 2>/dev/null   || echo "(empty)"
+
+    - name: Save cache
+      id: cache-save
+      uses: https://gitea.com/actions/cache@v3
+      with:
+        path: |
+          ~/.cargo/registry
+          ~/.cargo/git
+          ~/.rustup/toolchains
+          ~/.rustup/settings.toml
+          target
+        key: rust-linux-${{ steps.cache-key.outputs.hash }}
+        save-always: true
+
+    - name: Lookup same key immediately after save
+      id: cache-lookup
+      uses: https://gitea.com/actions/cache@v3
+      with:
+        path: ~/.cargo/registry
+        key: rust-linux-${{ steps.cache-key.outputs.hash }}
+        lookup-only: true
+
+    - name: Show sizes after cache
+      shell: bash
+      run: |
+        echo "=== ~/.cargo ===" && du -sh ~/.cargo 2>/dev/null || echo "(empty)"
+        echo "=== ~/.rustup ===" && du -sh ~/.rustup 2>/dev/null || echo "(empty)"
+        echo "save result: ${{ steps.cache-save.outputs.cache-hit }}"
+        echo "lookup result: ${{ steps.cache-lookup.outputs.cache-hit }}"