fix(ios): Honor shutdownTimeout on iOS

CHANGELOG.md

@@ -6,6 +6,12 @@
 > make sure you follow our [migration guide](https://docs.sentry.io/platforms/react-native/migration/) first.
 <!-- prettier-ignore-end -->
 
+## Unreleased
+
+### Fixes
+
+- Honor `shutdownTimeout` on iOS ([#6749](https://github.com/getsentry/sentry-react-native/pull/6749))
+
 ## 8.27.0
 
 > [!WARNING]

packages/core/RNSentryCocoaTester/RNSentryCocoaTesterTests/RNSentryStartTests.swift

@@ -245,6 +245,27 @@ final class RNSentryStartTests: XCTestCase {
         XCTAssertFalse(actualOptions.enableMemoryIntrospection)
     }
 
+    func testShutdownTimeoutMapsMillisecondsToSeconds() throws {
+        try startFromRN(options: [
+            "dsn": "https://abcd@efgh.ingest.sentry.io/123456",
+            // JS passes milliseconds; Cocoa's shutdownTimeInterval is in seconds
+            "shutdownTimeout": 5_000
+        ])
+
+        let actualOptions = SentrySDK.internal.options
+        XCTAssertEqual(actualOptions.shutdownTimeInterval, 5.0)
+    }
+
+    func testShutdownTimeoutDefault() throws {
+        try startFromRN(options: [
+            "dsn": "https://abcd@efgh.ingest.sentry.io/123456"
+        ])
+
+        let actualOptions = SentrySDK.internal.options
+        // Cocoa's default shutdownTimeInterval is 2 seconds
+        XCTAssertEqual(actualOptions.shutdownTimeInterval, 2.0)
+    }
+
     func startFromRN(options: [String: Any]) throws {
         var error: NSError?
         RNSentryStart.start(options: options, error: &error)

packages/core/ios/RNSentryStart.m

@@ -197,6 +197,15 @@ + (SentryOptions *_Nullable)createOptionsWithDictionary:(NSDictionary *_Nonnull)
         }
     }
 
+    // JS `shutdownTimeout` is in milliseconds (matching Android's `setShutdownTimeoutMillis`),
+    // while Cocoa's `shutdownTimeInterval` is an NSTimeInterval in seconds. The Cocoa dictionary
+    // parser only reads `shutdownTimeInterval`, so without this mapping the JS option is ignored on
+    // iOS and the native default is always used.
+    id shutdownTimeoutValue = [mutableOptions valueForKey:@"shutdownTimeout"];
+    if ([shutdownTimeoutValue isKindOfClass:[NSNumber class]]) {
+        sentryOptions.shutdownTimeInterval = [shutdownTimeoutValue doubleValue] / 1000.0;
+    }
+
     return sentryOptions;
 }