fix(client): require approximate modifier for XTRIM LIMIT

packages/client/lib/commands/XTRIM.spec.ts

@@ -34,12 +34,12 @@ describe('XTRIM', () => {
       );
     });
 
-    it('with LIMIT', () => {
+    it('with LIMIT without strategyModifier ~', () => {
       assert.deepEqual(
         parseArgs(XTRIM, 'key', 'MAXLEN', 1, {
           LIMIT: 1
         }),
-        ['XTRIM', 'key', 'MAXLEN', '1', 'LIMIT', '1']
+        ['XTRIM', 'key', 'MAXLEN', '1']
       );
     });
 
@@ -53,13 +53,13 @@ describe('XTRIM', () => {
       );
     });
 
-    it('with strategyModifier, LIMIT', () => {
+    it('with strategyModifier ~, LIMIT', () => {
       assert.deepEqual(
-        parseArgs(XTRIM, 'key', 'MAXLEN', 1, {
-          strategyModifier: '=',
-          LIMIT: 1
+        parseArgs(XTRIM, 'key', 'MINID', 5, {
+          strategyModifier: '~',
+          LIMIT: 2
         }),
-        ['XTRIM', 'key', 'MAXLEN', '=', '1', 'LIMIT', '1']
+        ['XTRIM', 'key', 'MINID', '~', '5', 'LIMIT', '2']
       );
     });
 

packages/client/lib/commands/XTRIM.ts

@@ -3,20 +3,34 @@ import { NumberReply, Command, RedisArgument } from '../RESP/types';
 import { StreamDeletionPolicy } from './common-stream.types';
 
 /**
- * Options for the XTRIM command
- * 
- * @property strategyModifier - Exact ('=') or approximate ('~') trimming
+ * Options for exact XTRIM trimming
+ *
+ * @property strategyModifier - Exact ('=') trimming
+ * @property policy - Policy to apply when deleting entries (optional, defaults to KEEPREF)
+ */
+export interface XTrimExactOptions {
+  strategyModifier?: '=';
+  /** added in 8.2 */
+  policy?: StreamDeletionPolicy;
+}
+
+/**
+ * Options for approximate XTRIM trimming
+ *
+ * @property strategyModifier - Approximate ('~') trimming, required for LIMIT
  * @property LIMIT - Maximum number of entries to trim in one call (Redis 6.2+)
  * @property policy - Policy to apply when deleting entries (optional, defaults to KEEPREF)
  */
-export interface XTrimOptions {
-  strategyModifier?: '=' | '~';
+export interface XTrimApproximateOptions {
+  strategyModifier: '~';
   /** added in 6.2 */
   LIMIT?: number;
   /** added in 8.2 */
   policy?: StreamDeletionPolicy;
 }
 
+export type XTrimOptions = XTrimExactOptions | XTrimApproximateOptions;
+
 /**
  * Command for trimming a stream to a specified length or minimum ID
  */
@@ -32,13 +46,13 @@ export default {
     parser.pushKey(key);
     parser.push(strategy);
 
-    if (options?.strategyModifier) {
+    if (options?.strategyModifier !== undefined) {
       parser.push(options.strategyModifier);
     }
 
     parser.push(threshold.toString());
 
-    if (options?.LIMIT !== undefined) {
+    if (options?.strategyModifier === '~' && options.LIMIT !== undefined) {
       parser.push('LIMIT', options.LIMIT.toString());
     }
 

packages/client/types-tests/xtrim-limit.types-test.ts

@@ -0,0 +1,20 @@
+/**
+ * Compile-time regression: XTRIM's LIMIT is only accepted by the server
+ * together with the approximate modifier ("syntax error, LIMIT cannot be used
+ * without the special ~ option", t_stream.c), so the options type must not
+ * allow LIMIT without strategyModifier '~'.
+ *
+ * Lives outside `lib/` so it is not picked up by the production build /
+ * typedoc. Checked with `npm run test:types -w @redis/client`.
+ */
+import { XTrimOptions } from '../lib/commands/XTRIM';
+
+export function xtrimLimitRequiresApproximateModifier(): void {
+    // LIMIT without '~' is rejected by the server.
+    // @ts-expect-error LIMIT requires strategyModifier '~'
+    const invalid: XTrimOptions = { LIMIT: 10 };
+
+    const valid: XTrimOptions = { strategyModifier: '~', LIMIT: 10 };
+
+    console.log(invalid, valid);
+}