From b7247c499bf71c5120218b2b025d32b37635aa8f Mon Sep 17 00:00:00 2001
From: Waleed Latif <walif6@gmail.com>
Date: Sat, 24 Oct 2026 11:33:56 -0700
Subject: [PATCH] fix(gmail): clear the history cursor only from a poll that
 held one

A search-mode poll (no stored cursor) sent historyId: undefined, which updateWebhookProviderConfig treats as a key removal. If it overlapped a newer poll that had just stored a cursor, it deleted that cursor. The poll state is now built once and carries historyId only when this poll started with a cursor or found one, so only a poll whose cursor Gmail rejected can clear it.
---
 apps/sim/lib/webhooks/polling/gmail.test.ts | 12 ++++++++++-
 apps/sim/lib/webhooks/polling/gmail.ts      | 23 +++++++--------------
 2 files changed, 18 insertions(+), 17 deletions(-)

diff --git a/apps/sim/lib/webhooks/polling/gmail.test.ts b/apps/sim/lib/webhooks/polling/gmail.test.ts
index 36de4423dc9..c1394a9dc82 100644
--- a/apps/sim/lib/webhooks/polling/gmail.test.ts
+++ b/apps/sim/lib/webhooks/polling/gmail.test.ts
@@ -136,7 +136,7 @@ function persistedHistoryIds() {
   )
 }
 
-describe('gmailPollingHandler expired history cursor', () => {
+describe('gmailPollingHandler history cursor', () => {
   beforeEach(() => {
     mockResolveOAuthCredential.mockResolvedValue('access-token')
     mockProcessEvent.mockResolvedValue({ success: true })
@@ -180,4 +180,14 @@ describe('gmailPollingHandler expired history cursor', () => {
 
     expect(persistedHistoryIds()).toEqual(['40100'])
   })
+
+  it('leaves the stored cursor untouched when a search-mode poll finds no mail', async () => {
+    mailboxWithExpiredHistory({ profileHistoryId: '40100', inboxMessages: [] })
+
+    await expect(gmailPollingHandler.pollWebhook(context({}))).resolves.toBe('success')
+
+    expect(mockUpdateConfig).toHaveBeenCalledTimes(1)
+    const [, updates] = mockUpdateConfig.mock.calls[0]
+    expect(updates).not.toHaveProperty('historyId')
+  })
 })
diff --git a/apps/sim/lib/webhooks/polling/gmail.ts b/apps/sim/lib/webhooks/polling/gmail.ts
index 780b911938e..97514ef5646 100644
--- a/apps/sim/lib/webhooks/polling/gmail.ts
+++ b/apps/sim/lib/webhooks/polling/gmail.ts
@@ -83,16 +83,14 @@ export const gmailPollingHandler: PollingProviderHandler = {
         requestId,
         logger
       )
+      const pollState = {
+        lastCheckedTimestamp: now.toISOString(),
+        // Omit unless this poll held a cursor, so it can't clear one an overlapping poll stored.
+        ...(config.historyId || latestHistoryId ? { historyId: latestHistoryId } : {}),
+      }
 
       if (!emails || !emails.length) {
-        await updateWebhookProviderConfig(
-          webhookId,
-          {
-            lastCheckedTimestamp: now.toISOString(),
-            historyId: latestHistoryId,
-          },
-          logger
-        )
+        await updateWebhookProviderConfig(webhookId, pollState, logger)
         await markWebhookSuccess(webhookId, logger)
         logger.info(`[${requestId}] No new emails found for webhook ${webhookId}`)
         return 'success'
@@ -110,14 +108,7 @@ export const gmailPollingHandler: PollingProviderHandler = {
         logger
       )
 
-      await updateWebhookProviderConfig(
-        webhookId,
-        {
-          lastCheckedTimestamp: now.toISOString(),
-          historyId: latestHistoryId,
-        },
-        logger
-      )
+      await updateWebhookProviderConfig(webhookId, pollState, logger)
 
       if (failedCount > 0 && processedCount === 0) {
         await markWebhookFailed(webhookId, logger)