fix: reinstall a cached package manager when its recorded bins are missing

sources/corepackUtils.ts

@@ -218,13 +218,24 @@ export async function installVersion(installTarget: string, locator: Locator, {s
 
     const corepackData = JSON.parse(corepackContent);
 
-    debugUtils.log(`Reusing ${locator.name}@${locator.reference} found in ${installFolder}`);
+    // An older Corepack may have recorded bin paths that the package doesn't
+    // ship (e.g. `bin/pnpm.cjs` for pnpm 12). Reinstall instead of running them.
+    const recordedBin: unknown = corepackData.bin;
+    const isStale = isValidBinSpec(recordedBin) &&
+      Object.values(recordedBin).every(dest => !fs.existsSync(path.join(installFolder, dest)));
+
+    if (!isStale) {
+      debugUtils.log(`Reusing ${locator.name}@${locator.reference} found in ${installFolder}`);
+
+      return {
+        hash: corepackData.hash as string,
+        location: installFolder,
+        bin: corepackData.bin,
+      };
+    }
 
-    return {
-      hash: corepackData.hash as string,
-      location: installFolder,
-      bin: corepackData.bin,
-    };
+    debugUtils.log(`Reinstalling ${locator.name}@${locator.reference}: none of its bins exist in ${installFolder}`);
+    await fs.promises.rm(installFolder, {recursive: true, force: true});
   } catch (err) {
     if (nodeUtils.isNodeError(err) && err.code !== `ENOENT`) {
       throw err;

tests/main.test.ts

@@ -1235,6 +1235,33 @@ it(`should handle parallel installs`, async () => {
   });
 });
 
+it(`should reinstall a cached package manager whose recorded bin is missing`, async () => {
+  await xfs.mktempPromise(async cwd => {
+    await xfs.writeJsonPromise(ppath.join(cwd, `package.json` as Filename), {
+      packageManager: `pnpm@6.6.2+sha224.eb5c0acad3b0f40ecdaa2db9aa5a73134ad256e17e22d1419a2ab073`,
+    });
+
+    await expect(runCli(cwd, [`pnpm`, `--version`])).resolves.toMatchObject({
+      exitCode: 0,
+      stderr: ``,
+      stdout: `6.6.2\n`,
+    });
+
+    // Simulate a record written by an older Corepack that pointed to a file the package doesn't ship.
+    const corepackFile = ppath.join(npath.toPortablePath(folderUtils.getInstallFolder()), `pnpm/6.6.2/.corepack` as PortablePath);
+    const record = await xfs.readJsonPromise(corepackFile);
+    await xfs.writeJsonPromise(corepackFile, {...record, bin: {pnpm: `./bin/missing.cjs`, pnpx: `./bin/missing.cjs`}});
+
+    await expect(runCli(cwd, [`pnpm`, `--version`])).resolves.toMatchObject({
+      exitCode: 0,
+      stderr: ``,
+      stdout: `6.6.2\n`,
+    });
+
+    await expect(xfs.readJsonPromise(corepackFile)).resolves.toMatchObject({bin: record.bin});
+  });
+});
+
 it(`should not override the package manager exit code`, async () => {
   await xfs.mktempPromise(async cwd => {
     await xfs.writeJsonPromise(ppath.join(cwd, `package.json` as Filename), {