From 7a5c4e95471ba5b892b3633b84846c62e82dbffa Mon Sep 17 00:00:00 2001
From: Raymond Hill <rhill@raymondhill.net>
Date: Tue, 17 Aug 2021 16:57:39 -0400
Subject: [PATCH] Throw when useLists() called concurrently

Related feedback:
- https://github.com/gorhill/uBlock/pull/3836/files#r690687656
---
 platform/nodejs/index.js | 10 +++++++++-
 1 file changed, 9 insertions(+), 1 deletion(-)

diff --git a/platform/nodejs/index.js b/platform/nodejs/index.js
index 08a65396d..e8c0171bb 100644
--- a/platform/nodejs/index.js
+++ b/platform/nodejs/index.js
@@ -146,6 +146,10 @@ function compileList({ name, raw }, compiler, writer, options = {}) {
 /******************************************************************************/
 
 async function useLists(lists, options = {}) {
+    if ( useLists.promise !== null ) {
+        throw new Error('Pending useLists() operation');
+    }
+
     // Remove all filters
     snfe.reset();
 
@@ -174,13 +178,17 @@ async function useLists(lists, options = {}) {
         promises.push(promise.then(list => consumeList(list)));
     }
 
-    await Promise.all(promises);
+    useLists.promise = Promise.all(promises);
+    await useLists.promise;
+    useLists.promise = null;
 
     // Commit changes
     snfe.freeze();
     snfe.optimize();
 }
 
+useLists.promise = null;
+
 /******************************************************************************/
 
 class MockStorage {