fix(connectors): validate Gmail's thread cap with the sync parser and reject invalid Date metadata

Author: waleedlatif1

apps/sim/connectors/gmail/gmail.test.ts

@@ -104,3 +104,14 @@ describe('gmail listDocuments with a blank maxThreads', () => {
     expect(mockFetchWithRetry).not.toHaveBeenCalled()
   })
 })
+
+describe('gmail validateConfig maxThreads', () => {
+  it('refuses what the sync parser would refuse, before any request', async () => {
+    for (const maxThreads of ['1.5', 'abc', '-1']) {
+      const result = await gmailConnector.validateConfig('token', { maxThreads })
+      expect(result.valid).toBe(false)
+      expect(result.error).toBe('Max threads must be a non-negative whole number')
+    }
+    expect(mockFetchWithRetry).not.toHaveBeenCalled()
+  })
+})

apps/sim/connectors/gmail/gmail.ts

@@ -565,10 +565,15 @@ export const gmailConnector: ConnectorConfig = {
     accessToken: string,
     sourceConfig: Record<string, unknown>
   ): Promise<{ valid: boolean; error?: string }> => {
-    const maxThreads = sourceConfig.maxThreads as string | undefined
-
-    if (maxThreads && (Number.isNaN(Number(maxThreads)) || Number(maxThreads) <= 0)) {
-      return { valid: false, error: 'Max threads must be a positive number' }
+    /** The same parser the sync uses, so a value that saves is a value that syncs. */
+    try {
+      parseDefaultedUnlimitedSafeInteger(
+        sourceConfig.maxThreads,
+        DEFAULT_MAX_THREADS,
+        'Max threads must be a non-negative whole number'
+      )
+    } catch (error) {
+      return { valid: false, error: getErrorMessage(error) }
     }
 
     try {

apps/sim/lib/knowledge/connectors/source-modified-at.test.ts

@@ -46,6 +46,10 @@ describe('resolveSourceModifiedAt', () => {
     ).toBe('2026-08-01T00:00:00.000Z')
   })
 
+  it('rejects an invalid Date instance', () => {
+    expect(resolveSourceModifiedAt({ modifiedTime: new Date('not a date') })).toBeNull()
+  })
+
   it('rejects placeholders and far-future values', () => {
     expect(resolveSourceModifiedAt({ modifiedTime: 0 }, NOW)).toBeNull()
     expect(resolveSourceModifiedAt({ modifiedTime: '1970-01-01T00:00:00Z' }, NOW)).toBeNull()

apps/sim/lib/knowledge/connectors/source-modified-at.ts

@@ -24,7 +24,7 @@ const EARLIEST_PLAUSIBLE_MS = Date.UTC(1990, 0, 1)
 const FUTURE_TOLERANCE_MS = 24 * 60 * 60 * 1000
 
 function toDate(value: unknown): Date | null {
-  if (value instanceof Date) return value
+  if (value instanceof Date) return Number.isNaN(value.getTime()) ? null : value
   if (typeof value === 'number' && Number.isFinite(value)) {
     /** Seconds-since-epoch values are far too small to be milliseconds after 1990. */
     return new Date(value < 1e11 ? value * 1000 : value)