feat: add step in enableYarn function to check if using the same Ya…

…rn version (#189)

src/yarn/index.test.ts

@@ -5,19 +5,49 @@ jest.unstable_mockModule("@actions/exec", () => ({
   getExecOutput: jest.fn(),
 }));
 
+jest.unstable_mockModule("./version.js", () => ({
+  getYarnVersion: jest.fn(),
+}));
+
 beforeEach(() => {
   jest.clearAllMocks();
 });
 
-it("should enable Yarn", async () => {
-  const { exec } = await import("@actions/exec");
-  const { enableYarn } = await import("./index.js");
+describe("enable Yarn", () => {
+  beforeEach(async () => {
+    const { getYarnVersion } = await import("./version.js");
+
+    jest.mocked(getYarnVersion).mockResolvedValue("1.2.3");
+  });
+
+  it("should enable Yarn", async () => {
+    const { exec } = await import("@actions/exec");
+    const { enableYarn } = await import("./index.js");
+
+    await expect(enableYarn()).resolves.toBeUndefined();
+
+    expect(exec).toHaveBeenCalledTimes(1);
+    expect(exec).toHaveBeenCalledWith("corepack", ["enable", "yarn"], {
+      silent: true,
+    });
+  });
+
+  describe("with different Yarn versions", () => {
+    beforeEach(async () => {
+      const { getYarnVersion } = await import("./version.js");
+
+      jest.mocked(getYarnVersion).mockImplementation(async (options) => {
+        return options?.corepack ? "1.2.3" : "1.2.4";
+      });
+    });
 
-  await enableYarn();
+    it("should failed to enable Yarn", async () => {
+      const { enableYarn } = await import("./index.js");
 
-  expect(exec).toHaveBeenCalledTimes(1);
-  expect(exec).toHaveBeenCalledWith("corepack", ["enable", "yarn"], {
-    silent: true,
+      await expect(enableYarn()).rejects.toThrow(
+        "The `yarn` command is using different version of Yarn, expected `1.2.3` but got `1.2.4`",
+      );
+    });
   });
 });
 

src/yarn/index.ts

@@ -1,9 +1,19 @@
 import { exec, getExecOutput } from "@actions/exec";
+import { getYarnVersion } from "./version.js";
 export { yarnInstall } from "./install.js";
 export { getYarnVersion } from "./version.js";
 
 export async function enableYarn(): Promise<void> {
   await exec("corepack", ["enable", "yarn"], { silent: true });
+
+  // Check if the `yarn` command is using the same version as the `corepack yarn` command.
+  const version = await getYarnVersion();
+  const corepackVersion = await getYarnVersion({ corepack: true });
+  if (version != corepackVersion) {
+    throw new Error(
+      `The \`yarn\` command is using different version of Yarn, expected \`${corepackVersion}\` but got \`${version}\``,
+    );
+  }
 }
 
 export async function getYarnConfig(name: string): Promise<string> {