From 37dc63a7e51e352aea4afc82f5aa6f118e015cfb Mon Sep 17 00:00:00 2001
From: Marco Saia <marco.saia@datadoghq.com>
Date: Wed, 27 May 2026 16:54:43 +0200
Subject: [PATCH] feat(core): remove hard attribute cap, warn at 256 limit

Remove the hard enforcement that silently dropped attributes beyond the
128-attribute cap. Update MAX_ATTRIBUTES to 256 to match the actual
backend limit and emit a single developer warning when that threshold is
exceeded, rather than dropping attributes. Aligns behaviour with the
iOS SDK change in dd-sdk-ios#2832.
---
 .../__tests__/attributesEncoding.test.ts      | 27 +++++++++----------
 .../src/sdk/AttributesEncoding/helpers.ts     | 27 +++++++------------
 2 files changed, 22 insertions(+), 32 deletions(-)

diff --git a/packages/core/src/sdk/AttributesEncoding/__tests__/attributesEncoding.test.ts b/packages/core/src/sdk/AttributesEncoding/__tests__/attributesEncoding.test.ts
index d9c9165a9..06a292431 100644
--- a/packages/core/src/sdk/AttributesEncoding/__tests__/attributesEncoding.test.ts
+++ b/packages/core/src/sdk/AttributesEncoding/__tests__/attributesEncoding.test.ts
@@ -216,7 +216,7 @@ describe('encodeAttributes', () => {
         );
     });
 
-    it('does not modify original object when attribute limit is reached', () => {
+    it('does not modify original object when encoding many attributes', () => {
         const input: Record<string, string> = {};
         for (let i = 0; i < 200; i++) {
             input[`k${i}`] = `v${i}`;
@@ -224,7 +224,7 @@ describe('encodeAttributes', () => {
         const snapshot = { ...input };
 
         const result = encodeAttributes(input);
-        expect(Object.keys(result)).toHaveLength(128);
+        expect(Object.keys(result)).toHaveLength(200);
         expect(input).toEqual(snapshot); // original still has 200 keys
     });
 
@@ -380,31 +380,30 @@ describe('encodeAttributes', () => {
         );
     });
 
-    it('drops attributes after reaching the 128 limit and warns once', () => {
-        // Prepare 200 simple attributes — max=128
+    it('warns once when the 256 attribute limit is exceeded, but does not drop attributes', () => {
+        // Prepare 300 simple attributes — exceeds max=256
         const input: Record<string, number> = {};
-        for (let i = 0; i < 200; i++) {
+        for (let i = 0; i < 300; i++) {
             input[`key${i}`] = i;
         }
 
         const result = encodeAttributes(input);
 
-        // Check that only 128 attributes remain
-        expect(Object.keys(result)).toHaveLength(128);
+        // All 300 attributes are preserved — no hard cap
+        expect(Object.keys(result)).toHaveLength(300);
 
-        // Check the first ones are preserved
+        // All attributes are present
         expect(result).toHaveProperty('key0', 0);
-        expect(result).toHaveProperty('key127', 127);
-
-        // Check later ones were dropped
-        expect(result).not.toHaveProperty('key128');
+        expect(result).toHaveProperty('key255', 255);
+        expect(result).toHaveProperty('key256', 256);
+        expect(result).toHaveProperty('key299', 299);
 
-        // Check that a warning was shown at least once
+        // A single warning is emitted when the limit is exceeded
         expect(warn).toHaveBeenCalledWith(
             expect.stringContaining('Attribute limit')
         );
 
-        // Check there is only one "limit reached" warning (even if multiple attributes were dropped)
+        // Exactly one "limit exceeded" warning (not one per extra attribute)
         const limitWarnings = (warn as jest.Mock).mock.calls.filter(([msg]) =>
             msg.includes('Attribute limit')
         );
diff --git a/packages/core/src/sdk/AttributesEncoding/helpers.ts b/packages/core/src/sdk/AttributesEncoding/helpers.ts
index 1fc80dece..c47762312 100644
--- a/packages/core/src/sdk/AttributesEncoding/helpers.ts
+++ b/packages/core/src/sdk/AttributesEncoding/helpers.ts
@@ -7,7 +7,7 @@
 import type { AttributeEncoder, Encodable } from './types';
 import { formatPathForLog, isPlainObject, warn } from './utils';
 
-const MAX_ATTRIBUTES = 128;
+const MAX_ATTRIBUTES = 256;
 
 export interface EncodeContext {
     numOfAttributes: number;
@@ -152,25 +152,16 @@ function addEncodedAttribute(
     value: Encodable,
     context: EncodeContext
 ): void {
-    if (context.numOfAttributes >= MAX_ATTRIBUTES) {
-        // Only warn once to avoid log spam
-        if (!context.limitReachedWarned) {
-            warn(
-                `Attribute limit of ${MAX_ATTRIBUTES} reached; further attributes will be dropped.`
-            );
-            context.limitReachedWarned = true;
-        }
+    out[path.join('.')] = value;
+    context.numOfAttributes++;
 
-        // Optional: warn for specific dropped attribute (if desired)
+    if (
+        context.numOfAttributes > MAX_ATTRIBUTES &&
+        !context.limitReachedWarned
+    ) {
         warn(
-            `Dropped attribute at '${formatPathForLog(
-                path
-            )}' because limit of ${MAX_ATTRIBUTES} attributes was reached. All further attributes will be dropped.`
+            `Attribute limit of ${MAX_ATTRIBUTES} exceeded; the backend may drop some attributes.`
         );
-
-        return;
+        context.limitReachedWarned = true;
     }
-
-    out[path.join('.')] = value;
-    context.numOfAttributes++;
 }