avoid stack overflow due to cached resolving

Author: sokra

lib/CachedInputFileSystem.js

@@ -171,8 +171,8 @@ class CacheBackend {
 		// Check in cache
 		let cacheEntry = this._data.get(path);
 		if (cacheEntry !== undefined) {
-			if (cacheEntry.err) return callback(cacheEntry.err);
-			return callback(null, cacheEntry.result);
+			if (cacheEntry.err) return process.nextTick(callback, cacheEntry.err);
+			return process.nextTick(callback, null, cacheEntry.result);
 		}
 
 		// Check if there is already the same operation running

test/CachedInputFileSystem.js

@@ -254,4 +254,18 @@ describe("CachedInputFileSystem CacheBackend", function () {
 			});
 		});
 	});
+
+	it("should not stack overflow when resolving in an async loop", done => {
+		let i = 10000;
+		const next = () => {
+			fs.stat(__dirname, (err, result) => {
+				if (i-- > 0) {
+					next();
+				} else {
+					done();
+				}
+			});
+		};
+		next();
+	});
 });