Basic implementation

src/save.ts

@@ -27,7 +27,9 @@ async function run(): Promise<void> {
         const state = utils.getCacheState();
 
         // Inputs are re-evaluted before the post action, so we want the original key used for restore
-        const primaryKey = core.getState(State.CachePrimaryKey);
+        const primaryKey =
+            core.getState(State.CachePrimaryKey) || core.getInput(Inputs.Key);
+
         if (!primaryKey) {
             utils.logWarning(`Error retrieving key from state.`);
             return;