From bad6607b2a4b6ef319e6c453bc2f6702f982cc21 Mon Sep 17 00:00:00 2001
From: Nik Ho <studying.mole@gmail.com>
Date: Tue, 10 Jun 2025 20:17:37 +1200
Subject: [PATCH 1/2] cache register user promise

---
 .../passport/sdk/src/zkEvm/zkEvmProvider.ts   | 50 +++++++++++++++----
 1 file changed, 39 insertions(+), 11 deletions(-)

diff --git a/packages/passport/sdk/src/zkEvm/zkEvmProvider.ts b/packages/passport/sdk/src/zkEvm/zkEvmProvider.ts
index 2955be92fc..aaed3e772a 100644
--- a/packages/passport/sdk/src/zkEvm/zkEvmProvider.ts
+++ b/packages/passport/sdk/src/zkEvm/zkEvmProvider.ts
@@ -77,6 +77,12 @@ export class ZkEvmProvider implements Provider {
 
   #signerInitialisationError: unknown | undefined;
 
+  /**
+   * Cache for the user registration promise to prevent race conditions
+   * when multiple eth_requestAccounts calls happen concurrently
+   */
+  #userRegistrationPromise?: Promise<string> | undefined;
+
   public readonly isPassport: boolean = true;
 
   constructor({
@@ -133,9 +139,17 @@ export class ZkEvmProvider implements Provider {
 
   #handleLogout = () => {
     this.#ethSigner = undefined;
+    this.#userRegistrationPromise = undefined;
     this.#providerEventEmitter.emit(ProviderEvent.ACCOUNTS_CHANGED, []);
   };
 
+  /**
+   * Clear the cached user registration promise
+   */
+  #clearUserRegistrationCache = () => {
+    this.#userRegistrationPromise = undefined;
+  };
+
   /**
    * This method is called by `eth_requestAccounts` and asynchronously initialises the signer.
    * The signer is stored in a promise so that it can be retrieved by the provider
@@ -247,18 +261,32 @@ export class ZkEvmProvider implements Provider {
           if (!isZkEvmUser(user)) {
             flow.addEvent('startUserRegistration');
 
-            const ethSigner = await this.#getSigner();
-            flow.addEvent('ethSignerResolved');
+            // Check if registration is already in progress to prevent race conditions
+            if (!this.#userRegistrationPromise) {
+              const ethSigner = await this.#getSigner();
+              flow.addEvent('ethSignerResolved');
+
+              // Cache the registration promise to prevent concurrent registrations
+              this.#userRegistrationPromise = registerZkEvmUser({
+                ethSigner,
+                authManager: this.#authManager,
+                multiRollupApiClients: this.#multiRollupApiClients,
+                accessToken: user.accessToken,
+                rpcProvider: this.#rpcProvider,
+                flow,
+              });
+            }
 
-            userZkEvmEthAddress = await registerZkEvmUser({
-              ethSigner,
-              authManager: this.#authManager,
-              multiRollupApiClients: this.#multiRollupApiClients,
-              accessToken: user.accessToken,
-              rpcProvider: this.#rpcProvider,
-              flow,
-            });
-            flow.addEvent('endUserRegistration');
+            try {
+              userZkEvmEthAddress = await this.#userRegistrationPromise;
+              flow.addEvent('endUserRegistration');
+              // Clear the cache after successful registration so future calls get fresh user data
+              this.#clearUserRegistrationCache();
+            } catch (error) {
+              // Clear the cached promise on error so it can be retried
+              this.#clearUserRegistrationCache();
+              throw error;
+            }
           } else {
             userZkEvmEthAddress = user.zkEvm.ethAddress;
           }

From 768d86d89d220c6365ecd46c77ef5388558d3b92 Mon Sep 17 00:00:00 2001
From: Nik Ho <studying.mole@gmail.com>
Date: Mon, 16 Jun 2025 16:57:25 +1200
Subject: [PATCH 2/2] finally clear cache

---
 packages/passport/sdk/src/zkEvm/zkEvmProvider.ts | 7 ++-----
 1 file changed, 2 insertions(+), 5 deletions(-)

diff --git a/packages/passport/sdk/src/zkEvm/zkEvmProvider.ts b/packages/passport/sdk/src/zkEvm/zkEvmProvider.ts
index aaed3e772a..2cc005e88b 100644
--- a/packages/passport/sdk/src/zkEvm/zkEvmProvider.ts
+++ b/packages/passport/sdk/src/zkEvm/zkEvmProvider.ts
@@ -280,12 +280,9 @@ export class ZkEvmProvider implements Provider {
             try {
               userZkEvmEthAddress = await this.#userRegistrationPromise;
               flow.addEvent('endUserRegistration');
-              // Clear the cache after successful registration so future calls get fresh user data
+            } finally {
+              // Clear the cache on success or error
               this.#clearUserRegistrationCache();
-            } catch (error) {
-              // Clear the cached promise on error so it can be retried
-              this.#clearUserRegistrationCache();
-              throw error;
             }
           } else {
             userZkEvmEthAddress = user.zkEvm.ethAddress;