From eb83954f23077c0714125b6f2f19fd0ef0f288f9 Mon Sep 17 00:00:00 2001
From: Adrien de Peretti <adrien.deperetti@gmail.com>
Date: Wed, 16 Jul 2025 16:34:47 +0200
Subject: [PATCH] chore(workflow-engine-*): Align event subscribers management
 (#12976)

* chore(workflow-engine-*): Align event subscribers management

* Create nervous-eels-build.md
---
 .changeset/nervous-eels-build.md              |  6 ++
 .../src/services/workflow-orchestrator.ts     | 25 ++++++--
 .../src/services/workflow-orchestrator.ts     | 58 ++++++++++++-------
 3 files changed, 62 insertions(+), 27 deletions(-)
 create mode 100644 .changeset/nervous-eels-build.md

diff --git a/.changeset/nervous-eels-build.md b/.changeset/nervous-eels-build.md
new file mode 100644
index 0000000000..7fe9a1e6e5
--- /dev/null
+++ b/.changeset/nervous-eels-build.md
@@ -0,0 +1,6 @@
+---
+"@medusajs/workflow-engine-inmemory": patch
+"@medusajs/workflow-engine-redis": patch
+---
+
+chore(workflow-engine-*): Align event subscribers management
diff --git a/packages/modules/workflow-engine-inmemory/src/services/workflow-orchestrator.ts b/packages/modules/workflow-engine-inmemory/src/services/workflow-orchestrator.ts
index b8455cad5c..c676afe73e 100644
--- a/packages/modules/workflow-engine-inmemory/src/services/workflow-orchestrator.ts
+++ b/packages/modules/workflow-engine-inmemory/src/services/workflow-orchestrator.ts
@@ -521,14 +521,16 @@ export class WorkflowOrchestratorService {
     const subscribers = this.subscribers.get(workflowId) ?? new Map()
 
     const handlerIndex = (handlers) => {
-      return handlers.indexOf((s) => s === subscriber || s._id === subscriberId)
+      return handlers.findIndex(
+        (s) => s === subscriber || s._id === subscriberId
+      )
     }
 
     if (transactionId) {
       const transactionSubscribers = subscribers.get(transactionId) ?? []
       const subscriberIndex = handlerIndex(transactionSubscribers)
       if (subscriberIndex !== -1) {
-        transactionSubscribers.slice(subscriberIndex, 1)
+        transactionSubscribers.splice(subscriberIndex, 1)
       }
 
       transactionSubscribers.push(subscriber)
@@ -540,7 +542,7 @@ export class WorkflowOrchestratorService {
     const workflowSubscribers = subscribers.get(AnySubscriber) ?? []
     const subscriberIndex = handlerIndex(workflowSubscribers)
     if (subscriberIndex !== -1) {
-      workflowSubscribers.slice(subscriberIndex, 1)
+      workflowSubscribers.splice(subscriberIndex, 1)
     }
 
     workflowSubscribers.push(subscriber)
@@ -568,14 +570,22 @@ export class WorkflowOrchestratorService {
       const newTransactionSubscribers = filterSubscribers(
         transactionSubscribers
       )
-      subscribers.set(transactionId, newTransactionSubscribers)
+      if (newTransactionSubscribers.length) {
+        subscribers.set(transactionId, newTransactionSubscribers)
+      } else {
+        subscribers.delete(transactionId)
+      }
       this.subscribers.set(workflowId, subscribers)
       return
     }
 
     const workflowSubscribers = subscribers.get(AnySubscriber) ?? []
     const newWorkflowSubscribers = filterSubscribers(workflowSubscribers)
-    subscribers.set(AnySubscriber, newWorkflowSubscribers)
+    if (newWorkflowSubscribers.length) {
+      subscribers.set(AnySubscriber, newWorkflowSubscribers)
+    } else {
+      subscribers.delete(AnySubscriber)
+    }
     this.subscribers.set(workflowId, subscribers)
   }
 
@@ -610,6 +620,10 @@ export class WorkflowOrchestratorService {
     if (transactionId) {
       const transactionSubscribers = subscribers.get(transactionId) ?? []
       notifySubscribers(transactionSubscribers)
+
+      if (options.eventType === "onFinish") {
+        subscribers.delete(transactionId)
+      }
     }
 
     const workflowSubscribers = subscribers.get(AnySubscriber) ?? []
@@ -664,7 +678,6 @@ export class WorkflowOrchestratorService {
         notify({ eventType: "onCompensateBegin" })
       },
       onFinish: ({ transaction, result, errors }) => {
-        // TODO: unsubscribe transaction handlers on finish
         customEventHandlers?.onFinish?.({ transaction, result, errors })
       },
 
diff --git a/packages/modules/workflow-engine-redis/src/services/workflow-orchestrator.ts b/packages/modules/workflow-engine-redis/src/services/workflow-orchestrator.ts
index f4b9c5b588..718125c08d 100644
--- a/packages/modules/workflow-engine-redis/src/services/workflow-orchestrator.ts
+++ b/packages/modules/workflow-engine-redis/src/services/workflow-orchestrator.ts
@@ -572,14 +572,16 @@ export class WorkflowOrchestratorService {
     }
 
     const handlerIndex = (handlers) => {
-      return handlers.indexOf((s) => s === subscriber || s._id === subscriberId)
+      return handlers.findIndex(
+        (s) => s === subscriber || s._id === subscriberId
+      )
     }
 
     if (transactionId) {
       const transactionSubscribers = subscribers.get(transactionId) ?? []
       const subscriberIndex = handlerIndex(transactionSubscribers)
       if (subscriberIndex !== -1) {
-        transactionSubscribers.slice(subscriberIndex, 1)
+        transactionSubscribers.splice(subscriberIndex, 1)
       }
 
       transactionSubscribers.push(subscriber)
@@ -591,7 +593,7 @@ export class WorkflowOrchestratorService {
     const workflowSubscribers = subscribers.get(AnySubscriber) ?? []
     const subscriberIndex = handlerIndex(workflowSubscribers)
     if (subscriberIndex !== -1) {
-      workflowSubscribers.slice(subscriberIndex, 1)
+      workflowSubscribers.splice(subscriberIndex, 1)
     }
 
     workflowSubscribers.push(subscriber)
@@ -604,7 +606,10 @@ export class WorkflowOrchestratorService {
     transactionId,
     subscriberOrId,
   }: UnsubscribeOptions) {
-    const subscribers = this.subscribers.get(workflowId) ?? new Map()
+    const subscribers = this.subscribers.get(workflowId)
+    if (!subscribers) {
+      return
+    }
 
     const filterSubscribers = (handlers: SubscriberHandler[]) => {
       return handlers.filter((handler) => {
@@ -614,25 +619,36 @@ export class WorkflowOrchestratorService {
       })
     }
 
-    // Unsubscribe instance
-    if (!this.subscribers.has(workflowId)) {
+    if (transactionId) {
+      const transactionSubscribers = subscribers.get(transactionId)
+      if (transactionSubscribers) {
+        const newTransactionSubscribers = filterSubscribers(
+          transactionSubscribers
+        )
+
+        if (newTransactionSubscribers.length) {
+          subscribers.set(transactionId, newTransactionSubscribers)
+        } else {
+          subscribers.delete(transactionId)
+        }
+      }
+    } else {
+      const workflowSubscribers = subscribers.get(AnySubscriber)
+      if (workflowSubscribers) {
+        const newWorkflowSubscribers = filterSubscribers(workflowSubscribers)
+
+        if (newWorkflowSubscribers.length) {
+          subscribers.set(AnySubscriber, newWorkflowSubscribers)
+        } else {
+          subscribers.delete(AnySubscriber)
+        }
+      }
+    }
+
+    if (subscribers.size === 0) {
+      this.subscribers.delete(workflowId)
       void this.redisSubscriber.unsubscribe(this.getChannelName(workflowId))
     }
-
-    if (transactionId) {
-      const transactionSubscribers = subscribers.get(transactionId) ?? []
-      const newTransactionSubscribers = filterSubscribers(
-        transactionSubscribers
-      )
-      subscribers.set(transactionId, newTransactionSubscribers)
-      this.subscribers.set(workflowId, subscribers)
-      return
-    }
-
-    const workflowSubscribers = subscribers.get(AnySubscriber) ?? []
-    const newWorkflowSubscribers = filterSubscribers(workflowSubscribers)
-    subscribers.set(AnySubscriber, newWorkflowSubscribers)
-    this.subscribers.set(workflowId, subscribers)
   }
 
   private async notify(