Also add "force-overwrite" option to save-only action

save/action.yml

@@ -15,6 +15,10 @@ inputs:
     description: 'An optional boolean when enabled, allows windows runners to save caches that can be restored on other platforms'
     default: 'false'
     required: false
+  force-overwrite:
+    description: 'Delete any previous (incremental) cache before pushing a new cache even if a cache for the primary cache key exists'
+    default: 'false'
+    required: false
 runs:
   using: 'node20'
   main: '../dist/save-only/index.js'

src/saveImpl.ts

@@ -56,7 +56,10 @@ export async function saveImpl(
             return;
         }
 
-        if (utils.isExactKeyMatch(primaryKey, restoredKey) && forceOverwrite) {
+        if ((restoredKey == undefined || utils.isExactKeyMatch(primaryKey, restoredKey)) && forceOverwrite) {
+            core.info(
+                `Cache hit occurred on the primary key ${primaryKey} or running as save-only and force-overwrite is enabled, deleting cache for key ${primaryKey}.`
+            );
             await issueCommand('actions-cache delete', {}, primaryKey);
         }