No-op on GHES

__tests__/restore.test.ts

@@ -53,6 +53,30 @@ test("restore with invalid event outputs warning", async () => {
     expect(failedMock).toHaveBeenCalledTimes(0);
 });
 
+test("restore on GHES should no-op", async () => {
+    try {
+        process.env["GITHUB_SERVER_URL"] = "http://example.com";
+
+        const infoMock = jest.spyOn(core, "info");
+        const restoreCacheMock = jest.spyOn(cache, "restoreCache");
+        const setCacheHitOutputMock = jest.spyOn(
+            actionUtils,
+            "setCacheHitOutput"
+        );
+
+        await run();
+
+        expect(restoreCacheMock).toHaveBeenCalledTimes(0);
+        expect(setCacheHitOutputMock).toHaveBeenCalledTimes(1);
+        expect(setCacheHitOutputMock).toHaveBeenCalledWith(false);
+        expect(infoMock).toHaveBeenCalledWith(
+            "Cache action is not supported on GHES"
+        );
+    } finally {
+        process.env["GITHUB_SERVER_URL"] = undefined;
+    }
+});
+
 test("restore with no path should fail", async () => {
     const failedMock = jest.spyOn(core, "setFailed");
     const restoreCacheMock = jest.spyOn(cache, "restoreCache");

__tests__/save.test.ts

@@ -91,6 +91,24 @@ test("save with no primary key in state outputs warning", async () => {
     expect(failedMock).toHaveBeenCalledTimes(0);
 });
 
+test("save on GHES should no-op", async () => {
+    try {
+        process.env["GITHUB_SERVER_URL"] = "http://example.com";
+
+        const infoMock = jest.spyOn(core, "info");
+        const saveCacheMock = jest.spyOn(cache, "saveCache");
+
+        await run();
+
+        expect(saveCacheMock).toHaveBeenCalledTimes(0);
+        expect(infoMock).toHaveBeenCalledWith(
+            "Cache action is not supported on GHES"
+        );
+    } finally {
+        process.env["GITHUB_SERVER_URL"] = undefined;
+    }
+});
+
 test("save with exact match returns early", async () => {
     const infoMock = jest.spyOn(core, "info");
     const failedMock = jest.spyOn(core, "setFailed");

src/restore.ts

@@ -6,6 +6,12 @@ import * as utils from "./utils/actionUtils";
 
 async function run(): Promise<void> {
     try {
+        if (utils.isGhes()) {
+            core.info("Cache action is not supported on GHES");
+            utils.setCacheHitOutput(false);
+            return;
+        }
+
         // Validate inputs, this can cause task failure
         if (!utils.isValidEvent()) {
             utils.logWarning(

src/save.ts

@@ -6,6 +6,11 @@ import * as utils from "./utils/actionUtils";
 
 async function run(): Promise<void> {
     try {
+        if (utils.isGhes()) {
+            core.info("Cache action is not supported on GHES");
+            return;
+        }
+
         if (!utils.isValidEvent()) {
             utils.logWarning(
                 `Event Validation Error: The event type ${

src/utils/actionUtils.ts

@@ -2,6 +2,13 @@ import * as core from "@actions/core";
 
 import { Outputs, RefKey, State } from "../constants";
 
+export function isGhes(): boolean {
+    const ghUrl = new URL(
+        process.env["GITHUB_SERVER_URL"] || "https://github.com"
+    );
+    return ghUrl.hostname.toUpperCase() !== "GITHUB.COM";
+}
+
 export function isExactKeyMatch(key: string, cacheKey?: string): boolean {
     return !!(
         cacheKey &&