fix: remove in & not in operators for hasMany: false relationship fields

packages/ui/src/elements/WhereBuilder/reduceFields.tsx

@@ -130,7 +130,15 @@ export const reduceFields = ({
     if (typeof fieldTypes[field.type] === 'object') {
       const operatorKeys = new Set()
 
-      const operators = fieldTypes[field.type].operators.reduce((acc, operator) => {
+      let fieldTypeOperators = [...fieldTypes[field.type].operators]
+
+      if (field.type === 'relationship' && field.hasMany !== true) {
+        fieldTypeOperators = fieldTypeOperators.filter(
+          (op) => op.value !== 'in' && op.value !== 'not_in',
+        )
+      }
+
+      const operators = fieldTypeOperators.reduce((acc, operator) => {
         if (!operatorKeys.has(operator.value)) {
           operatorKeys.add(operator.value)
           const operatorKey = `operators:${operator.label}` as ClientTranslationKeys

test/fields/collections/Relationship/e2e.spec.ts

@@ -4,6 +4,7 @@ import { expect, test } from '@playwright/test'
 import { addListFilter } from 'helpers/e2e/addListFilter.js'
 import { navigateToDoc } from 'helpers/e2e/navigateToDoc.js'
 import { openDocControls } from 'helpers/e2e/openDocControls.js'
+import { openListFilters } from 'helpers/e2e/openListFilters.js'
 import { openCreateDocDrawer, openDocDrawer } from 'helpers/e2e/toggleDocDrawer.js'
 import path from 'path'
 import { wait } from 'payload/shared'
@@ -650,6 +651,36 @@ describe('relationship', () => {
 
     await expect(page.locator(tableRowLocator)).toHaveCount(1)
   })
+
+  test('should not allow filtering by relationship field hasMany false / in & not in', async () => {
+    await page.goto(url.list)
+
+    await openListFilters(page, {})
+
+    const whereBuilder = page.locator('.where-builder')
+
+    await whereBuilder.locator('.where-builder__add-first-filter').click()
+
+    const conditionField = whereBuilder.locator('.condition__field')
+    await conditionField.click()
+
+    await conditionField
+      .locator('.rs__option', {
+        hasText: exactText('Relationship'),
+      })
+      ?.click()
+
+    await expect(whereBuilder.locator('.condition__field')).toContainText('Relationship')
+
+    const operatorInput = whereBuilder.locator('.condition__operator')
+    await operatorInput.click()
+
+    const operatorOptions = operatorInput.locator('.rs__option')
+    const optionTexts = await operatorOptions.allTextContents()
+
+    await expect.poll(() => optionTexts).not.toContain('is in')
+    await expect.poll(() => optionTexts).not.toContain('is not in')
+  })
 })
 
 async function createTextFieldDoc(overrides?: Partial<TextField>): Promise<TextField> {