Remove rejected promises from the cache

Summary: Rejected promises in the cache would prevent the cache from persisting. This removes rejected promises from the cache, so that subsequent successful cache updates can be persisted.

Reviewed By: cpojer

Differential Revision: D3726691

fbshipit-source-id: ddec03676a7a89264fe64b4af4b183cbead638fb

packager/react-packager/src/node-haste/Cache/__tests__/Cache-test.js

@@ -153,6 +153,30 @@ describe('Cache', () => {
           )
         );
     });
+
+    it('does not cache rejections', () => {
+      fs.stat.mockImpl((file, callback) => {
+        callback(null, {
+          mtime: {
+            getTime: () => {},
+          },
+        });
+      });
+
+      var cache = new Cache({
+        cacheKey: 'cache',
+      });
+      var loaderCb = () => Promise.reject('lol');
+
+      return cache
+        .get('/rootDir/someFile', 'field', loaderCb)
+        .catch(() => {
+          var shouldBeCalled = jest.fn(() => Promise.resolve());
+          const assert = value => expect(shouldBeCalled).toBeCalled();
+          return cache.get('/rootDir/someFile', 'field', shouldBeCalled)
+            .then(assert, assert);
+        });
+    });
   });
 
   describe('loading cache from disk', () => {

packager/react-packager/src/node-haste/Cache/index.js

@@ -87,7 +87,7 @@ class Cache {
       this._data[filepath].metadata = Object.create(null);
     }
 
-    record.data[field] = loaderPromise
+    const cachedPromise = record.data[field] = loaderPromise
       .then(data => Promise.all([
         data,
         denodeify(fs.stat)(filepath),
@@ -106,7 +106,9 @@ class Cache {
         return data;
       });
 
-    return record.data[field];
+    // don't cache rejected promises
+    cachedPromise.catch(error => delete record.data[field]);
+    return cachedPromise;
   }
 
   _persistCache() {