Added cache-hit output

__tests__/cache-restore.test.ts

@@ -191,6 +191,37 @@ virtualenvs.path = "{cache-dir}/virtualenvs"  # /Users/patrick/Library/Caches/py
     );
   });
 
+  describe('Check if handleMatchResult', () => {
+    it.each([
+      ['pip', '3.8.12', 'requirements.txt', 'someKey', true],
+      ['pipenv', '3.9.1', 'requirements.txt', 'someKey', true],
+      ['poetry', '3.8.12', 'requirements.txt', 'someKey', true],
+      ['pip', '3.9.2', 'requirements.txt', undefined, false],
+      ['pipenv', '3.8.12', 'requirements.txt', undefined, false],
+      ['poetry', '3.9.12', 'requirements.txt', undefined, false]
+    ])(
+      'sets correct outputs',
+      async (
+        packageManager,
+        pythonVersion,
+        dependencyFile,
+        matchedKey,
+        expectedOutputValue
+      ) => {
+        const cacheDistributor = getCacheDistributor(
+          packageManager,
+          pythonVersion,
+          dependencyFile
+        );
+        cacheDistributor.handleMatchResult(matchedKey);
+        expect(setOutputSpy).toHaveBeenCalledWith(
+          'cache-hit',
+          expectedOutputValue
+        );
+      }
+    );
+  });
+
   afterEach(() => {
     jest.resetAllMocks();
     jest.clearAllMocks();

action.yml

@@ -19,6 +19,8 @@ inputs:
 outputs:
   python-version:
     description: "The installed python version. Useful when given a version range as input."
+  cache-hit:
+    description: 'A boolean value to indicate a cache entry was found'
 runs:
   using: 'node16'
   main: 'dist/setup/index.js'

src/cache-distributions/cache-distributor.ts

@@ -1,5 +1,6 @@
 import * as cache from '@actions/cache';
 import * as core from '@actions/core';
+import {PromiseReturnType} from '../utils';
 
 export enum State {
   STATE_CACHE_PRIMARY_KEY = 'cache-primary-key',
@@ -41,12 +42,19 @@ abstract class CacheDistributor {
       restoreKey
     );
 
+    this.handleMatchResult(matchedKey);
+  }
+
+  public handleMatchResult(
+    matchedKey: PromiseReturnType<typeof cache.restoreCache>
+  ) {
     if (matchedKey) {
       core.saveState(State.CACHE_MATCHED_KEY, matchedKey);
       core.info(`Cache restored from key: ${matchedKey}`);
     } else {
       core.info(`${this.packageManager} cache is not found`);
     }
+    core.setOutput('cache-hit', Boolean(matchedKey));
   }
 }
 

src/utils.ts

@@ -119,3 +119,12 @@ export function isCacheFeatureAvailable(): boolean {
 
   return true;
 }
+
+// Awaited (typescript 4.5+) polyfill. Not ideal, so use with care
+export type AwaitedPolyfill<T> = T extends PromiseLike<infer U>
+  ? AwaitedPolyfill<U>
+  : T;
+// Extract return type from promise
+export type PromiseReturnType<
+  T extends (...args: any) => any
+> = AwaitedPolyfill<ReturnType<T>>;