fix(profiling): iOS UI profiling on v8

`RNSentryStart.createOptionsWithDictionary` (the live iOS init path
since v8.0.0) did not read `_experiments.profilingOptions`, silently
dropping `profileSessionSampleRate`, `lifecycle`, and `startOnAppStart`.
The handling existed in `SentrySDKWrapper`, but that surface hasn't
been called from `initNativeSdk` since #5582 — #5611 added the block
to the wrong file.

Port the handling to `RNSentryStart` and add XCTest coverage for the
`startWithOptions` entry point that `initNativeSdk` uses, so this
regression can't slip through again.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

Author: antonis

CHANGELOG.md

@@ -12,6 +12,10 @@
 
 - Warn Expo users at Metro startup when prebuilt native projects are missing Sentry configuration ([#5984](https://github.com/getsentry/sentry-react-native/pull/5984))
 
+### Fixes
+
+- fix(profiling): iOS UI profiling on v8
+
 ## 8.8.0
 
 ### Features

packages/core/RNSentryCocoaTester/RNSentryCocoaTesterTests/RNSentryTests.m

@@ -5,6 +5,7 @@
 #import <OCMock/OCMock.h>
 #import <RNSentry/RNSentry.h>
 #import <Sentry/PrivateSentrySDKOnly.h>
+#import <Sentry/SentryProfilingConditionals.h>
 #import <UIKit/UIKit.h>
 #import <XCTest/XCTest.h>
 @import Sentry;
@@ -1372,6 +1373,91 @@ - (void)testStartBeforeBreadcrumbsCallbackDoesNotFiltersOutNonDevServerOrDsnRequ
     XCTAssertEqual(breadcrumb, result);
 }
 
+#if SENTRY_TARGET_PROFILING_SUPPORTED
+// Regression test for the v8.0.0 bug where the init path (RNSentryStart) did not
+// handle `_experiments.profilingOptions`, silently dropping iOS UI profiling config.
+// This pins the full entry point used by `initNativeSdk` in RNSentry.mm.
+- (void)testStartWithDictionaryInstallsConfigureProfilingFromExperimentsProfilingOptions
+{
+    NSError *error = nil;
+
+    NSDictionary *_Nonnull mockedReactNativeDictionary = @{
+        @"dsn" : @"https://abcd@efgh.ingest.sentry.io/123456",
+        @"_experiments" : @ {
+            @"profilingOptions" : @ {
+                @"profileSessionSampleRate" : @1.0,
+                @"lifecycle" : @"trace",
+                @"startOnAppStart" : @YES,
+            },
+        },
+    };
+    [RNSentryStart startWithOptions:mockedReactNativeDictionary error:&error];
+    SentryOptions *actualOptions = PrivateSentrySDKOnly.options;
+
+    XCTAssertNotNil(actualOptions, @"Did not create sentry options");
+    XCTAssertNil(error, @"Should not pass no error");
+    XCTAssertNotNil(actualOptions.configureProfiling,
+        @"configureProfiling must be installed after startWithOptions when profilingOptions is "
+        @"present");
+}
+
+- (void)testStartCreateOptionsWithDictionaryProfilingOptionsInstallsConfigureProfiling
+{
+    NSError *error = nil;
+
+    NSDictionary *_Nonnull mockedReactNativeDictionary = @{
+        @"dsn" : @"https://abcd@efgh.ingest.sentry.io/123456",
+        @"_experiments" : @ {
+            @"profilingOptions" : @ {
+                @"profileSessionSampleRate" : @1.0,
+                @"lifecycle" : @"trace",
+                @"startOnAppStart" : @YES,
+            },
+        },
+    };
+    SentryOptions *actualOptions =
+        [RNSentryStart createOptionsWithDictionary:mockedReactNativeDictionary error:&error];
+
+    XCTAssertNotNil(actualOptions, @"Did not create sentry options");
+    XCTAssertNil(error, @"Should not pass no error");
+    XCTAssertNotNil(actualOptions.configureProfiling,
+        @"configureProfiling callback should be installed when profilingOptions is present");
+}
+
+- (void)testStartCreateOptionsWithDictionaryProfilingOptionsMissingDoesNotInstallConfigureProfiling
+{
+    NSError *error = nil;
+
+    NSDictionary *_Nonnull mockedReactNativeDictionary = @{
+        @"dsn" : @"https://abcd@efgh.ingest.sentry.io/123456",
+    };
+    SentryOptions *actualOptions =
+        [RNSentryStart createOptionsWithDictionary:mockedReactNativeDictionary error:&error];
+
+    XCTAssertNotNil(actualOptions, @"Did not create sentry options");
+    XCTAssertNil(error, @"Should not pass no error");
+    XCTAssertNil(actualOptions.configureProfiling,
+        @"configureProfiling callback should not be installed without profilingOptions");
+}
+
+- (void)testStartCreateOptionsWithDictionaryEmptyExperimentsDoesNotInstallConfigureProfiling
+{
+    NSError *error = nil;
+
+    NSDictionary *_Nonnull mockedReactNativeDictionary = @{
+        @"dsn" : @"https://abcd@efgh.ingest.sentry.io/123456",
+        @"_experiments" : @ { },
+    };
+    SentryOptions *actualOptions =
+        [RNSentryStart createOptionsWithDictionary:mockedReactNativeDictionary error:&error];
+
+    XCTAssertNotNil(actualOptions, @"Did not create sentry options");
+    XCTAssertNil(error, @"Should not pass no error");
+    XCTAssertNil(actualOptions.configureProfiling,
+        @"configureProfiling callback should not be installed when profilingOptions is absent");
+}
+#endif
+
 - (void)testStartEventFromSentryCocoaReactNativeHasOriginAndEnvironmentTags
 {
     SentryEvent *testEvent = [[SentryEvent alloc] init];

packages/core/ios/RNSentryStart.m

@@ -100,6 +100,16 @@ + (SentryOptions *_Nullable)createOptionsWithDictionary:(NSDictionary *_Nonnull)
         }
     }
 
+    // Configure iOS UI Profiling from _experiments.profilingOptions
+    NSDictionary *experiments = mutableOptions[@"_experiments"];
+    if (experiments != nil && [experiments isKindOfClass:[NSDictionary class]]) {
+        NSDictionary *profilingOptions = experiments[@"profilingOptions"];
+        if (profilingOptions != nil && [profilingOptions isKindOfClass:[NSDictionary class]]) {
+            [RNSentryExperimentalOptions configureProfilingWithOptions:profilingOptions
+                                                         sentryOptions:sentryOptions];
+        }
+    }
+
     // Set strict trace continuation options
     if ([mutableOptions valueForKey:@"strictTraceContinuation"] != nil) {
         sentryOptions.strictTraceContinuation =