From 8386d9644f2def7fb7948d9d53d12da4a0a1503b Mon Sep 17 00:00:00 2001
From: Alexander Pantiukhov <alex@apantiukhov.com>
Date: Thu, 4 Dec 2025 16:17:05 +0100
Subject: [PATCH 1/4] feat(metrics): A fix for metrics

---
 packages/core/src/js/index.ts                     | 3 ++-
 packages/core/src/js/wrapper.ts                   | 7 +++----
 samples/react-native/src/Screens/ErrorsScreen.tsx | 4 ++--
 3 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/packages/core/src/js/index.ts b/packages/core/src/js/index.ts
index d43df01c5f..6d251cad10 100644
--- a/packages/core/src/js/index.ts
+++ b/packages/core/src/js/index.ts
@@ -13,6 +13,7 @@ export type {
   UserFeedback,
   ErrorEvent,
   TransactionEvent,
+  Metric,
 } from '@sentry/core';
 
 export {
@@ -46,7 +47,6 @@ export {
   setCurrentClient,
   addEventProcessor,
   lastEventId,
-  metrics,
 } from '@sentry/core';
 
 export {
@@ -63,6 +63,7 @@ export {
   consoleLoggingIntegration,
   featureFlagsIntegration,
   type FeatureFlagsIntegration,
+  metrics,
 } from '@sentry/browser';
 
 export * from './integrations/exports';
diff --git a/packages/core/src/js/wrapper.ts b/packages/core/src/js/wrapper.ts
index 3ac01e6498..7752e2fe96 100644
--- a/packages/core/src/js/wrapper.ts
+++ b/packages/core/src/js/wrapper.ts
@@ -182,17 +182,16 @@ export const NATIVE: SentryNativeWrapper = {
     for (const rawItem of envelopeItems) {
       const [itemHeader, itemPayload] = this._processItem(rawItem);
 
-      let bytesContentType: string;
+      let bytesContentType: string =
+        typeof itemHeader.content_type === 'string' ? itemHeader.content_type : 'application/octet-stream';
       let bytesPayload: number[] | Uint8Array | undefined;
+
       if (typeof itemPayload === 'string') {
         bytesContentType = 'text/plain';
         bytesPayload = encodeUTF8(itemPayload);
       } else if (itemPayload instanceof Uint8Array) {
-        bytesContentType =
-          typeof itemHeader.content_type === 'string' ? itemHeader.content_type : 'application/octet-stream';
         bytesPayload = itemPayload;
       } else {
-        bytesContentType = 'application/vnd.sentry.items.log+json';
         bytesPayload = encodeUTF8(JSON.stringify(itemPayload));
         if (!hardCrashed) {
           hardCrashed = isHardCrash(itemPayload);
diff --git a/samples/react-native/src/Screens/ErrorsScreen.tsx b/samples/react-native/src/Screens/ErrorsScreen.tsx
index 62682038a3..a03022a351 100644
--- a/samples/react-native/src/Screens/ErrorsScreen.tsx
+++ b/samples/react-native/src/Screens/ErrorsScreen.tsx
@@ -127,9 +127,9 @@ const ErrorsScreen = (_props: Props) => {
           }}
         />
         <Button
-          title="Send distribution metric"
+          title="Send count metric with attributes"
           onPress={() => {
-            Sentry.metrics.count('distribution_metric', 100);
+            Sentry.metrics.count('count_metric', 100, { attributes: { from_test_app: true } });
           }}
         />
         <Button

From b1b8c32059e50b39946b4ff04700f42a2f4fae55 Mon Sep 17 00:00:00 2001
From: Alexander Pantiukhov <alex@apantiukhov.com>
Date: Fri, 5 Dec 2025 10:02:31 +0100
Subject: [PATCH 2/4] Updated tests

---
 packages/core/test/wrapper.test.ts | 129 +++++++++++++++++++++++++++--
 1 file changed, 122 insertions(+), 7 deletions(-)

diff --git a/packages/core/test/wrapper.test.ts b/packages/core/test/wrapper.test.ts
index 8b2ead16c9..af05908564 100644
--- a/packages/core/test/wrapper.test.ts
+++ b/packages/core/test/wrapper.test.ts
@@ -1,4 +1,12 @@
-import type { Event, EventEnvelope, EventItem, SeverityLevel } from '@sentry/core';
+import type {
+  EnvelopeItem,
+  Event,
+  EventEnvelope,
+  EventItem,
+ LogEnvelope,  LogSeverityLevel,
+  MetricEnvelope,
+  MetricType,
+  SeverityLevel } from '@sentry/core';
 import { createEnvelope, debug } from '@sentry/core';
 import * as RN from 'react-native';
 import type { Spec } from '../src/js/NativeRNSentry';
@@ -391,7 +399,7 @@ describe('Tests Native Wrapper', () => {
         base64StringFromByteArray(
           utf8ToBytes(
             '{"event_id":"event0","sent_at":"123"}\n' +
-              '{"type":"event","content_type":"application/vnd.sentry.items.log+json","length":87}\n' +
+              '{"type":"event","content_type":"application/octet-stream","length":87}\n' +
               '{"event_id":"event0","message":"test","sdk":{"name":"test-sdk-name","version":"2.1.3"}}\n',
           ),
         ),
@@ -423,7 +431,7 @@ describe('Tests Native Wrapper', () => {
         base64StringFromByteArray(
           utf8ToBytes(
             '{"event_id":"event0","sent_at":"123"}\n' +
-              '{"type":"event","content_type":"application/vnd.sentry.items.log+json","length":93}\n' +
+              '{"type":"event","content_type":"application/octet-stream","length":93}\n' +
               '{"event_id":"event0","sdk":{"name":"test-sdk-name","version":"2.1.3"},"instance":{"value":0}}\n',
           ),
         ),
@@ -466,7 +474,7 @@ describe('Tests Native Wrapper', () => {
         base64StringFromByteArray(
           utf8ToBytes(
             '{"event_id":"event0","sent_at":"123"}\n' +
-              '{"type":"event","content_type":"application/vnd.sentry.items.log+json","length":50}\n' +
+              '{"type":"event","content_type":"application/octet-stream","length":50}\n' +
               '{"event_id":"event0","message":{"message":"test"}}\n',
           ),
         ),
@@ -505,7 +513,7 @@ describe('Tests Native Wrapper', () => {
         base64StringFromByteArray(
           utf8ToBytes(
             '{"event_id":"event0","sent_at":"123"}\n' +
-              '{"type":"event","content_type":"application/vnd.sentry.items.log+json","length":124}\n' +
+              '{"type":"event","content_type":"application/octet-stream","length":124}\n' +
               '{"event_id":"event0","exception":{"values":[{"mechanism":{"handled":true,"type":""}}]},"breadcrumbs":[{"message":"crumb!"}]}\n',
           ),
         ),
@@ -534,7 +542,7 @@ describe('Tests Native Wrapper', () => {
         base64StringFromByteArray(
           utf8ToBytes(
             '{"event_id":"event0","sent_at":"123"}\n' +
-              '{"type":"event","content_type":"application/vnd.sentry.items.log+json","length":58}\n' +
+              '{"type":"event","content_type":"application/octet-stream","length":58}\n' +
               '{"event_id":"event0","breadcrumbs":[{"message":"crumb!"}]}\n',
           ),
         ),
@@ -573,13 +581,120 @@ describe('Tests Native Wrapper', () => {
         base64StringFromByteArray(
           utf8ToBytes(
             '{"event_id":"event0","sent_at":"123"}\n' +
-              '{"type":"event","content_type":"application/vnd.sentry.items.log+json","length":132}\n' +
+              '{"type":"event","content_type":"application/octet-stream","length":132}\n' +
               '{"event_id":"event0","exception":{"values":[{"mechanism":{"handled":false,"type":"onerror"}}]},"breadcrumbs":[{"message":"crumb!"}]}\n',
           ),
         ),
         { hardCrashed: true },
       );
     });
+
+    test('preserves content_type for logs (application/vnd.sentry.items.log+json)', async () => {
+      const logPayload = {
+        timestamp: 1234567890,
+        level: 'info' as LogSeverityLevel,
+        body: 'test log message',
+        logger: 'test-logger',
+      };
+
+      const env = createEnvelope<LogEnvelope>({ event_id: 'log0', sent_at: '123' }, [
+        [
+          {
+            type: 'log',
+            content_type: 'application/vnd.sentry.items.log+json',
+            item_count: 1,
+          },
+          { items: [logPayload] },
+        ],
+      ]);
+
+      await NATIVE.sendEnvelope(env);
+
+      const expectedPayload = JSON.stringify({ items: [logPayload] });
+      const expectedLength = utf8ToBytes(expectedPayload).length;
+
+      expect(RNSentry.captureEnvelope).toHaveBeenCalledWith(
+        base64StringFromByteArray(
+          utf8ToBytes(
+            '{"event_id":"log0","sent_at":"123"}\n' +
+              `{"type":"log","content_type":"application/vnd.sentry.items.log+json","item_count":1,"length":${expectedLength}}\n` +
+              `${expectedPayload}\n`,
+          ),
+        ),
+        { hardCrashed: false },
+      );
+    });
+
+    test('preserves content_type for metrics (application/vnd.sentry.items.trace-metric+json)', async () => {
+      const metricsPayload = {
+        timestamp: 1234567890,
+        trace_id: 'trace_id',
+        name: 'metric.name',
+        type: 'counter' as MetricType,
+        value: 42,
+        measurements: {
+          'metric.name': { value: 42 },
+        },
+      };
+
+      const env = createEnvelope<MetricEnvelope>({ event_id: 'metric0', sent_at: '123' }, [
+        [
+          {
+            type: 'trace_metric',
+            content_type: 'application/vnd.sentry.items.trace-metric+json',
+            item_count: 1,
+          },
+          { items: [metricsPayload] },
+        ],
+      ]);
+
+      await NATIVE.sendEnvelope(env);
+
+      const expectedPayload = JSON.stringify({ items: [metricsPayload] });
+      const expectedLength = utf8ToBytes(expectedPayload).length;
+
+      expect(RNSentry.captureEnvelope).toHaveBeenCalledWith(
+        base64StringFromByteArray(
+          utf8ToBytes(
+            '{"event_id":"metric0","sent_at":"123"}\n' +
+              `{"type":"trace_metric","content_type":"application/vnd.sentry.items.trace-metric+json","item_count":1,"length":${expectedLength}}\n` +
+              `${expectedPayload}\n`,
+          ),
+        ),
+        { hardCrashed: false },
+      );
+    });
+
+    test('preserves custom content_type when provided', async () => {
+      const payload = {
+        event_id: 'event0',
+        message: 'test',
+      };
+      const env = createEnvelope({ event_id: 'foo1', sent_at: '123' }, [
+        [
+          {
+            type: 'event',
+            content_type: 'application/custom-type',
+          },
+          payload,
+        ],
+      ]);
+
+      await NATIVE.sendEnvelope(env);
+
+      const expectedPayload = JSON.stringify(payload);
+      const expectedLength = utf8ToBytes(expectedPayload).length;
+      expect(RNSentry.captureEnvelope).toHaveBeenCalledWith(
+        base64StringFromByteArray(
+          utf8ToBytes(
+            '{"event_id":"foo1","sent_at":"123"}\n' +
+              `{"type":"event","content_type":"application/custom-type","length":${expectedLength}}\n` +
+              `${expectedPayload}\n`,
+          ),
+        ),
+        { hardCrashed: false },
+      );
+    });
   });
 
   describe('fetchRelease', () => {

From 4de2525f70a401555a4e46a96f4d9318b4728310 Mon Sep 17 00:00:00 2001
From: Alexander Pantiukhov <alex@apantiukhov.com>
Date: Fri, 5 Dec 2025 13:29:37 +0100
Subject: [PATCH 3/4] Fixes

---
 packages/core/src/js/wrapper.ts    |  6 ++++--
 packages/core/test/wrapper.test.ts | 18 ++++++++++--------
 2 files changed, 14 insertions(+), 10 deletions(-)

diff --git a/packages/core/src/js/wrapper.ts b/packages/core/src/js/wrapper.ts
index 7752e2fe96..8552cdac7c 100644
--- a/packages/core/src/js/wrapper.ts
+++ b/packages/core/src/js/wrapper.ts
@@ -182,16 +182,18 @@ export const NATIVE: SentryNativeWrapper = {
     for (const rawItem of envelopeItems) {
       const [itemHeader, itemPayload] = this._processItem(rawItem);
 
-      let bytesContentType: string =
-        typeof itemHeader.content_type === 'string' ? itemHeader.content_type : 'application/octet-stream';
+      let bytesContentType: string;
       let bytesPayload: number[] | Uint8Array | undefined;
 
       if (typeof itemPayload === 'string') {
         bytesContentType = 'text/plain';
         bytesPayload = encodeUTF8(itemPayload);
       } else if (itemPayload instanceof Uint8Array) {
+        bytesContentType =
+          typeof itemHeader.content_type === 'string' ? itemHeader.content_type : 'application/octet-stream';
         bytesPayload = itemPayload;
       } else {
+        bytesContentType = typeof itemHeader.content_type === 'string' ? itemHeader.content_type : 'application/json';
         bytesPayload = encodeUTF8(JSON.stringify(itemPayload));
         if (!hardCrashed) {
           hardCrashed = isHardCrash(itemPayload);
diff --git a/packages/core/test/wrapper.test.ts b/packages/core/test/wrapper.test.ts
index af05908564..6b19644d4c 100644
--- a/packages/core/test/wrapper.test.ts
+++ b/packages/core/test/wrapper.test.ts
@@ -3,10 +3,12 @@ import type {
   Event,
   EventEnvelope,
   EventItem,
- LogEnvelope,  LogSeverityLevel,
+  LogEnvelope,
+  LogSeverityLevel,
   MetricEnvelope,
   MetricType,
-  SeverityLevel } from '@sentry/core';
+  SeverityLevel,
+} from '@sentry/core';
 import { createEnvelope, debug } from '@sentry/core';
 import * as RN from 'react-native';
 import type { Spec } from '../src/js/NativeRNSentry';
@@ -399,7 +401,7 @@ describe('Tests Native Wrapper', () => {
         base64StringFromByteArray(
           utf8ToBytes(
             '{"event_id":"event0","sent_at":"123"}\n' +
-              '{"type":"event","content_type":"application/octet-stream","length":87}\n' +
+              '{"type":"event","content_type":"application/json","length":87}\n' +
               '{"event_id":"event0","message":"test","sdk":{"name":"test-sdk-name","version":"2.1.3"}}\n',
           ),
         ),
@@ -431,7 +433,7 @@ describe('Tests Native Wrapper', () => {
         base64StringFromByteArray(
           utf8ToBytes(
             '{"event_id":"event0","sent_at":"123"}\n' +
-              '{"type":"event","content_type":"application/octet-stream","length":93}\n' +
+              '{"type":"event","content_type":"application/json","length":93}\n' +
               '{"event_id":"event0","sdk":{"name":"test-sdk-name","version":"2.1.3"},"instance":{"value":0}}\n',
           ),
         ),
@@ -474,7 +476,7 @@ describe('Tests Native Wrapper', () => {
         base64StringFromByteArray(
           utf8ToBytes(
             '{"event_id":"event0","sent_at":"123"}\n' +
-              '{"type":"event","content_type":"application/octet-stream","length":50}\n' +
+              '{"type":"event","content_type":"application/json","length":50}\n' +
               '{"event_id":"event0","message":{"message":"test"}}\n',
           ),
         ),
@@ -513,7 +515,7 @@ describe('Tests Native Wrapper', () => {
         base64StringFromByteArray(
           utf8ToBytes(
             '{"event_id":"event0","sent_at":"123"}\n' +
-              '{"type":"event","content_type":"application/octet-stream","length":124}\n' +
+              '{"type":"event","content_type":"application/json","length":124}\n' +
               '{"event_id":"event0","exception":{"values":[{"mechanism":{"handled":true,"type":""}}]},"breadcrumbs":[{"message":"crumb!"}]}\n',
           ),
         ),
@@ -542,7 +544,7 @@ describe('Tests Native Wrapper', () => {
         base64StringFromByteArray(
           utf8ToBytes(
             '{"event_id":"event0","sent_at":"123"}\n' +
-              '{"type":"event","content_type":"application/octet-stream","length":58}\n' +
+              '{"type":"event","content_type":"application/json","length":58}\n' +
               '{"event_id":"event0","breadcrumbs":[{"message":"crumb!"}]}\n',
           ),
         ),
@@ -581,7 +583,7 @@ describe('Tests Native Wrapper', () => {
         base64StringFromByteArray(
           utf8ToBytes(
             '{"event_id":"event0","sent_at":"123"}\n' +
-              '{"type":"event","content_type":"application/octet-stream","length":132}\n' +
+              '{"type":"event","content_type":"application/json","length":132}\n' +
               '{"event_id":"event0","exception":{"values":[{"mechanism":{"handled":false,"type":"onerror"}}]},"breadcrumbs":[{"message":"crumb!"}]}\n',
           ),
         ),

From 355204022cf19c6a4f5571f33c9f6e1feb67820b Mon Sep 17 00:00:00 2001
From: Alexander Pantiukhov <alex@apantiukhov.com>
Date: Fri, 5 Dec 2025 14:57:03 +0100
Subject: [PATCH 4/4] Lint fiix

---
 packages/core/test/wrapper.test.ts | 1 -
 1 file changed, 1 deletion(-)

diff --git a/packages/core/test/wrapper.test.ts b/packages/core/test/wrapper.test.ts
index 6b19644d4c..cc7b79c0d9 100644
--- a/packages/core/test/wrapper.test.ts
+++ b/packages/core/test/wrapper.test.ts
@@ -1,5 +1,4 @@
 import type {
-  EnvelopeItem,
   Event,
   EventEnvelope,
   EventItem,