From f83fc2986ea9222e68d2e24013876a208a655f15 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Nicol=C3=B2=20Ribaudo?= <nicolo.ribaudo@gmail.com>
Date: Mon, 7 Oct 2019 12:37:03 +0200
Subject: [PATCH] Cleanup

---
 packages/babel-core/src/config/caching.js     | 52 +++++++++----------
 .../babel-core/src/gensync-utils/async.js     |  2 +-
 2 files changed, 26 insertions(+), 28 deletions(-)

diff --git a/packages/babel-core/src/config/caching.js b/packages/babel-core/src/config/caching.js
index 1ad7050f5db4..fcad6e8fccbe 100644
--- a/packages/babel-core/src/config/caching.js
+++ b/packages/babel-core/src/config/caching.js
@@ -1,7 +1,5 @@
 // @flow
 
-/*:: declare var invariant; */
-
 import gensync, { type Handler } from "gensync";
 import {
   maybeAsync,
@@ -73,6 +71,31 @@ export function makeStrongCacheSync<ArgT, ResultT, SideChannel>(
   );
 }
 
+/* NOTE: Part of the logic explained in this comment is explained in the
+ *       getCachedValueOrWait and setupAsyncLocks functions.
+ *
+ * > There are only two hard things in Computer Science: cache invalidation and naming things.
+ * > -- Phil Karlton
+ *
+ * I don't know if Phil was also thinking about handling a cache whose invalidation function is
+ * defined asynchronously is considered, but it is REALLY hard to do correctly.
+ *
+ * The implemented logic (only when gensync is run asynchronously) is the following:
+ *   1. If there is a valid cache associated to the current "arg" parameter,
+ *       a. RETURN the cached value
+ *   3. If there is a FinishLock associated to the current "arg" parameter representing a valid cache,
+ *       a. Wait for that lock to be released
+ *       b. RETURN the value associated with that lock
+ *   5. Start executing the function to be cached
+ *       a. If it pauses on a promise, then
+ *           i. Let FinishLock be a new lock
+ *          ii. Store FinishLock as associated to the current "arg" parameter
+ *         iii. Wait for the function to finish executing
+ *          iv. Release FinishLock
+ *           v. Send the function result to anyone waiting on FinishLock
+ *   6. Store the result in the cache
+ *   7. RETURN the result
+ */
 function makeCachedFunction<ArgT, ResultT, SideChannel, Cache: *>(
   CallCache: Class<Cache>,
   handler: (ArgT, CacheConfigurator<SideChannel>) => Handler<ResultT> | ResultT,
@@ -150,30 +173,6 @@ function* getCachedValue<
   return { valid: false, value: null };
 }
 
-/* NOTE: This comment refers to both the getCachedValueOrWait and setupAsyncLocks functions.
- *
- * > There are only two hard things in Computer Science: cache invalidation and naming things.
- * > -- Phil Karlton
- *
- * I don't know if Phil was also thinking about handling a cache whose invalidation function is
- * defined asynchronously is considered, but it is REALLY hard to do correctly.
- *
- * The implemented logic (only when gensync is run asynchronously) is the following:
- *   1. If there is a valid cache associated to the current "arg" parameter,
- *       a. RETURN the cached value
- *   3. If there is a FinishLock associated to the current "arg" parameter representing a valid cache,
- *       a. Wait for that lock to be released
- *       b. RETURN the value associated with that lock
- *   5. Start executing the function to be cached
- *       a. If it pauses on a promise, then
- *           i. Let FinishLock be a new lock
- *          ii. Store FinishLock as associated to the current "arg" parameter
- *         iii. Wait for the function to finish executing
- *          iv. Release FinishLock
- *           v. Send the function result to anyone waiting on FinishLock
- *   6. Store the result in the cache
- *   7. RETURN the result
- */
 function* getCachedValueOrWait<ArgT, ResultT, SideChannel>(
   asyncContext: boolean,
   callCache: CacheMap<ArgT, ResultT, SideChannel>,
@@ -253,7 +252,6 @@ class CacheConfigurator<SideChannel = void> {
   _invalidate: boolean = false;
 
   _configured: boolean = false;
-  _configuredHandler: ?Function = null;
 
   _pairs: Array<[mixed, (SideChannel) => Handler<mixed>]> = [];
 
diff --git a/packages/babel-core/src/gensync-utils/async.js b/packages/babel-core/src/gensync-utils/async.js
index 5fd44e39357c..84edcc394135 100644
--- a/packages/babel-core/src/gensync-utils/async.js
+++ b/packages/babel-core/src/gensync-utils/async.js
@@ -14,7 +14,7 @@ const runGenerator = gensync(function*(item) {
 // asynchronous, otherwise it returns false.
 export const isAsync = gensync<[], boolean>({
   sync: () => false,
-  async: async () => true,
+  errback: cb => cb(null, true),
 });
 
 // This function wraps any functions (which could be either synchronous or