Reject empty filter membership arrays

src/commands/analytics.ts

@@ -4,6 +4,7 @@ import {
   hasTinybirdMembershipDelimiter,
   isCanonicalFilterOperator,
   isCanonicalFilterValue,
+  isEmptyMembershipArray,
   isValuelessFilterOperator,
 } from '../lib/filters'
 import { parseJsonObject } from '../lib/json'
@@ -87,6 +88,9 @@ function validateAnalyticsFilter(
   if (!isCanonicalFilterOperator(record.op)) {
     throw new Error(`${path} requires a canonical "op"`)
   }
+  if (isEmptyMembershipArray(record.value)) {
+    throw new Error(`${path}: membership arrays cannot be empty`)
+  }
   if (
     !isValuelessFilterOperator(record.op) &&
     (record.value === undefined ||

src/commands/profiles.ts

@@ -2,6 +2,7 @@ import { Cli, z } from 'incur'
 import { createClient, requireApiKey } from '../lib/client'
 import {
   isCanonicalFilterOperator,
+  isEmptyMembershipArray,
   isValuelessFilterOperator,
 } from '../lib/filters'
 import {
@@ -194,6 +195,9 @@ export function parseSearchFilters(raw: string): unknown[] {
         '--filters: each entry must use a canonical "op" (eq, neq, gt, lt, gte, lte, in, nin, startsWith, endsWith, contains, notEmpty, or isEmpty)',
       )
     }
+    if (isEmptyMembershipArray(record.value)) {
+      throw new Error('--filters: membership arrays cannot be empty')
+    }
     if (
       !isValuelessFilterOperator(record.op) &&
       (record.value === undefined || record.value === null)

src/commands/segments.ts

@@ -4,6 +4,7 @@ import {
   hasTinybirdMembershipDelimiter,
   isCanonicalFilterValue,
   isCanonicalFilterOperator,
+  isEmptyMembershipArray,
   isValuelessFilterOperator,
 } from '../lib/filters'
 import { parseJsonArray } from '../lib/json'
@@ -70,6 +71,9 @@ export function buildCreateSegmentBody(options: CreateSegmentOptions) {
     if (!isCanonicalFilterOperator(record.op)) {
       throw new Error('--filters: each entry requires a canonical "op"')
     }
+    if (isEmptyMembershipArray(record.value)) {
+      throw new Error('--filters: membership arrays cannot be empty')
+    }
     if (
       !isValuelessFilterOperator(record.op) &&
       (record.value === undefined ||

src/lib/filters.ts

@@ -32,12 +32,17 @@ export function isCanonicalFilterValue(value: unknown): boolean {
     typeof value === 'number' ||
     typeof value === 'boolean' ||
     (Array.isArray(value) &&
+      value.length > 0 &&
       value.every(
         (item) => typeof item === 'string' || typeof item === 'number',
       ))
   )
 }
 
+export function isEmptyMembershipArray(value: unknown): boolean {
+  return Array.isArray(value) && value.length === 0
+}
+
 export function hasTinybirdMembershipDelimiter(value: unknown): boolean {
   return (
     Array.isArray(value) &&

test/commands/analytics.test.ts

@@ -119,6 +119,28 @@ describe('commands/analytics', function () {
       ).to.throw(/cannot contain "\|"/);
     });
 
+    it('rejects empty membership arrays, including nested filters', function () {
+      expect(() =>
+        buildAnalyticsParams({
+          filters: JSON.stringify([
+            { field: 'browser', op: 'in', value: [] },
+          ]),
+        }),
+      ).to.throw(/membership arrays cannot be empty/);
+      expect(() =>
+        buildAnalyticsParams({
+          filters: JSON.stringify([
+            {
+              field: 'event',
+              op: 'eq',
+              value: 'purchase',
+              filters: [{ field: 'sku', op: 'nin', value: [] }],
+            },
+          ]),
+        }),
+      ).to.throw(/membership arrays cannot be empty/);
+    });
+
     it('merges primitive params through unchanged', function () {
       const params = buildAnalyticsParams({
         params: '{"limit":10,"group_by":"device"}',

test/commands/bodyBuilders.test.ts

@@ -455,6 +455,14 @@ describe('commands / body builders', function () {
         parseSearchFilters('[{"field":"users.browser","op":"notEmpty"}]'),
       ).to.not.throw();
     });
+
+    it('rejects empty membership arrays', function () {
+      expect(() =>
+        parseSearchFilters(
+          '[{"field":"users.browser","op":"in","value":[]}]',
+        ),
+      ).to.throw(/membership arrays cannot be empty/);
+    });
   });
 
   // ── Input validation guards ──

test/commands/segments.test.ts

@@ -25,5 +25,14 @@ describe('commands/segments', function () {
       expect(() => createSegmentRun({ title: 'x', filters: '5' })).to.throw(/filters/);
       expect(() => createSegmentRun({ title: 'x', filters: '"foo"' })).to.throw(/filters/);
     });
+
+    it('rejects empty membership arrays', function () {
+      expect(() =>
+        createSegmentRun({
+          title: 'x',
+          filters: '[{"field":"browser","op":"in","value":[]}]',
+        }),
+      ).to.throw(/membership arrays cannot be empty/);
+    });
   });
 });