From d6e78c306c8150c58277d60e51edac55a55523c2 Mon Sep 17 00:00:00 2001
From: Paolo Insogna <paolo@cowtech.it>
Date: Fri, 16 Oct 2020 15:26:07 +0200
Subject: [PATCH] fix: Ensure delayed callbacks are always invoked.

---
 lib/autoPipelining.ts | 14 ++++++++------
 lib/cluster/index.ts  | 26 ++++++++++++++------------
 lib/pipeline.ts       |  9 +++++++--
 lib/transaction.ts    |  9 +++++++--
 4 files changed, 36 insertions(+), 22 deletions(-)

diff --git a/lib/autoPipelining.ts b/lib/autoPipelining.ts
index 617d348d..45e7b64f 100644
--- a/lib/autoPipelining.ts
+++ b/lib/autoPipelining.ts
@@ -88,12 +88,14 @@ export function executeWithAutoPipelining(
   // On cluster mode let's wait for slots to be available
   if (client.isCluster && !client.slots.length) {
     return new CustomPromise(function (resolve, reject) {
-      client.delayUntilReady(() => {
-        executeWithAutoPipelining(client, commandName, args, callback).then(
-          resolve,
-          reject
-        );
-      });
+      client.delayUntilReady(err => {
+        if (err) {
+          reject(err);
+          return;
+        }
+
+        executeWithAutoPipelining(client, commandName, args, callback).then(resolve, reject);
+      })
     });
   }
 
diff --git a/lib/cluster/index.ts b/lib/cluster/index.ts
index 7db4e831..6796b714 100644
--- a/lib/cluster/index.ts
+++ b/lib/cluster/index.ts
@@ -227,6 +227,7 @@ class Cluster extends EventEmitter {
 
           let closeListener: () => void = undefined;
           const refreshListener = () => {
+            this.invokeReadyDelayedCallbacks(undefined);
             this.removeListener("close", closeListener);
             this.manuallyClosing = false;
             this.setStatus("connect");
@@ -250,8 +251,11 @@ class Cluster extends EventEmitter {
           };
 
           closeListener = function () {
+            const error = new Error("None of startup nodes is available");
+
             this.removeListener("refresh", refreshListener);
-            reject(new Error("None of startup nodes is available"));
+            this.invokeReadyDelayedCallbacks(error);
+            reject(error);
           };
 
           this.once("refresh", refreshListener);
@@ -271,6 +275,7 @@ class Cluster extends EventEmitter {
         .catch((err) => {
           this.setStatus("close");
           this.handleCloseEvent(err);
+          this.invokeReadyDelayedCallbacks(err);
           reject(err);
         });
     });
@@ -440,17 +445,6 @@ class Cluster extends EventEmitter {
 
   // This is needed in order not to install a listener for each auto pipeline
   public delayUntilReady(callback: CallbackFunction) {
-    // First call, setup the event listener
-    if (!this._readyDelayedCallbacks.length) {
-      this.once("ready", (...args) => {
-        for (const c of this._readyDelayedCallbacks) {
-          c(...args);
-        }
-
-        this._readyDelayedCallbacks = [];
-      });
-    }
-
     this._readyDelayedCallbacks.push(callback);
   }
 
@@ -850,6 +844,14 @@ class Cluster extends EventEmitter {
     );
   }
 
+  private invokeReadyDelayedCallbacks(err) {
+    for (const c of this._readyDelayedCallbacks) {
+      process.nextTick(c, err);
+    }
+  
+    this._readyDelayedCallbacks = [];
+  }
+
   /**
    * Check whether Cluster is able to process commands
    *
diff --git a/lib/pipeline.ts b/lib/pipeline.ts
index 3e3e8d6c..194ee5a4 100644
--- a/lib/pipeline.ts
+++ b/lib/pipeline.ts
@@ -236,9 +236,14 @@ Pipeline.prototype.execBuffer = deprecate(function () {
 Pipeline.prototype.exec = function (callback: CallbackFunction) {
   // Wait for the cluster to be connected, since we need nodes information before continuing
   if (this.isCluster && !this.redis.slots.length) {
-    this.redis.delayUntilReady(() => {
+    this.redis.delayUntilReady(err => {
+      if (err) {
+        callback(err);
+        return;
+      }
+
       this.exec(callback);
-    });
+    })
 
     return this.promise;
   }
diff --git a/lib/transaction.ts b/lib/transaction.ts
index 6e0952b6..41583cfc 100644
--- a/lib/transaction.ts
+++ b/lib/transaction.ts
@@ -32,9 +32,14 @@ export function addTransactionSupport(redis) {
       if (this.isCluster && !this.redis.slots.length) {
         return asCallback(
           new Promise((resolve, reject) => {
-            this.redis.delayUntilReady(() => {
+            this.redis.delayUntilReady(err => {
+              if (err) {
+                reject(err);
+                return;
+              }
+
               this.exec(pipeline).then(resolve, reject);
-            });
+            })
           }),
           callback
         );