Always output explicit "false" to prevent hijacking

__tests__/restore.test.ts

@@ -177,7 +177,7 @@ test("restore with cache found for key", async () => {
     expect(setCacheHitOutputMock).toHaveBeenCalledWith("cache-hit", "true");
     expect(setCacheHitOutputMock).toHaveBeenCalledWith(
         "save-always-d18d746b9",
-        ""
+        "false"
     );
 
     expect(infoMock).toHaveBeenCalledWith(`Cache restored from key: ${key}`);
@@ -226,7 +226,7 @@ test("restore with cache found for restore key", async () => {
     expect(setCacheHitOutputMock).toHaveBeenCalledWith("cache-hit", "false");
     expect(setCacheHitOutputMock).toHaveBeenCalledWith(
         "save-always-d18d746b9",
-        ""
+        "false"
     );
     expect(infoMock).toHaveBeenCalledWith(
         `Cache restored from key: ${restoreKey}`
@@ -271,7 +271,7 @@ test("Fail restore when fail on cache miss is enabled and primary + restore keys
     expect(setCacheHitOutputMock).toHaveBeenCalledTimes(1);
     expect(setCacheHitOutputMock).toHaveBeenCalledWith(
         "save-always-d18d746b9",
-        ""
+        "false"
     );
 
     expect(failedMock).toHaveBeenCalledWith(
@@ -322,7 +322,7 @@ test("restore when fail on cache miss is enabled and primary key doesn't match r
     expect(setCacheHitOutputMock).toHaveBeenCalledWith("cache-hit", "false");
     expect(setCacheHitOutputMock).toHaveBeenCalledWith(
         "save-always-d18d746b9",
-        ""
+        "false"
     );
 
     expect(infoMock).toHaveBeenCalledWith(

__tests__/restoreImpl.test.ts

@@ -83,7 +83,7 @@ test("restore without AC available should no-op", async () => {
     expect(setCacheHitOutputMock).toHaveBeenCalledWith("cache-hit", "false");
     expect(setCacheHitOutputMock).toHaveBeenCalledWith(
         "save-always-d18d746b9",
-        ""
+        "false"
     );
 });
 
@@ -103,7 +103,7 @@ test("restore on GHES without AC available should no-op", async () => {
     expect(setCacheHitOutputMock).toHaveBeenCalledWith("cache-hit", "false");
     expect(setCacheHitOutputMock).toHaveBeenCalledWith(
         "save-always-d18d746b9",
-        ""
+        "false"
     );
 });
 
@@ -145,7 +145,7 @@ test("restore on GHES with AC available ", async () => {
     expect(setCacheHitOutputMock).toHaveBeenCalledWith("cache-hit", "true");
     expect(setCacheHitOutputMock).toHaveBeenCalledWith(
         "save-always-d18d746b9",
-        ""
+        "false"
     );
 
     expect(infoMock).toHaveBeenCalledWith(`Cache restored from key: ${key}`);
@@ -371,7 +371,7 @@ test("restore with cache found for key", async () => {
     expect(setCacheHitOutputMock).toHaveBeenCalledWith("cache-hit", "true");
     expect(setCacheHitOutputMock).toHaveBeenCalledWith(
         "save-always-d18d746b9",
-        ""
+        "false"
     );
 
     expect(infoMock).toHaveBeenCalledWith(`Cache restored from key: ${key}`);
@@ -417,7 +417,7 @@ test("restore with cache found for restore key", async () => {
     expect(setCacheHitOutputMock).toHaveBeenCalledWith("cache-hit", "false");
     expect(setCacheHitOutputMock).toHaveBeenCalledWith(
         "save-always-d18d746b9",
-        ""
+        "false"
     );
     expect(infoMock).toHaveBeenCalledWith(
         `Cache restored from key: ${restoreKey}`
@@ -465,7 +465,7 @@ test("restore with lookup-only set", async () => {
     expect(setCacheHitOutputMock).toHaveBeenCalledWith("cache-hit", "true");
     expect(setCacheHitOutputMock).toHaveBeenCalledWith(
         "save-always-d18d746b9",
-        ""
+        "false"
     );
 
     expect(infoMock).toHaveBeenCalledWith(

__tests__/restoreOnly.test.ts

@@ -86,7 +86,7 @@ test("restore with no cache found", async () => {
     );
 
     expect(outputMock).toHaveBeenCalledWith("cache-primary-key", key);
-    expect(outputMock).toHaveBeenCalledWith("save-always-d18d746b9", "");
+    expect(outputMock).toHaveBeenCalledWith("save-always-d18d746b9", "false");
     expect(outputMock).toHaveBeenCalledTimes(2);
     expect(failedMock).toHaveBeenCalledTimes(0);
 
@@ -170,7 +170,7 @@ test("restore with cache found for key", async () => {
     expect(outputMock).toHaveBeenCalledWith("cache-primary-key", key);
     expect(outputMock).toHaveBeenCalledWith("cache-hit", "true");
     expect(outputMock).toHaveBeenCalledWith("cache-matched-key", key);
-    expect(outputMock).toHaveBeenCalledWith("save-always-d18d746b9", "");
+    expect(outputMock).toHaveBeenCalledWith("save-always-d18d746b9", "false");
 
     expect(outputMock).toHaveBeenCalledTimes(4);
 
@@ -214,7 +214,7 @@ test("restore with cache found for restore key", async () => {
     expect(outputMock).toHaveBeenCalledWith("cache-primary-key", key);
     expect(outputMock).toHaveBeenCalledWith("cache-hit", "false");
     expect(outputMock).toHaveBeenCalledWith("cache-matched-key", restoreKey);
-    expect(outputMock).toHaveBeenCalledWith("save-always-d18d746b9", "");
+    expect(outputMock).toHaveBeenCalledWith("save-always-d18d746b9", "false");
 
     expect(outputMock).toHaveBeenCalledTimes(4);
 

src/restoreImpl.ts

@@ -13,7 +13,10 @@ export async function restoreImpl(
     stateProvider: IStateProvider,
     earlyExit?: boolean | undefined
 ): Promise<string | undefined> {
-    core.setOutput(Outputs.SaveAlways, core.getInput(Inputs.SaveAlways));
+    core.setOutput(
+        Outputs.SaveAlways,
+        core.getInput(Inputs.SaveAlways) || "false"
+    );
 
     try {
         if (!utils.isCacheFeatureAvailable()) {