feat(tracing): sync JS scope propagation context to native scope by alwx · Pull Request #6686 · getsentry/sentry-react-native

alwx · 2026-09-08T12:30:38Z

📢 Type of change

Bugfix
New feature
Enhancement
Refactoring

📜 Description

Adds a new setCurrentScopePropagationContext bridge method that pushes the active JS root span's traceId, spanId, sampled, and sampleRand to the native SDK scope whenever a new root span starts. Wired up automatically via a spanStart hook in reactNativeTracingIntegration.

💡 Motivation and Context

Fixes #6237.

Native HTTP spans (OkHttp on Android, URLSession on iOS) were always orphaned — they had no knowledge of the active JS trace and ended up as standalone transactions in Sentry. After this change, native spans automatically share the same trace_id as the JS navigation transaction that triggered them.

JS: syncPropagationContextToNative(client) registers a spanStart hook (root spans only) and calls NATIVE.setCurrentScopePropagationContext({ traceId, spanId, sampled, sampleRand }).
Android: PropagationContext.fromExistingTrace(traceId, spanId, sampled, sampleRand) applied via Sentry.configureScope.
iOS: SentrySDK.internal.setTrace(_:spanId:) called through RNSentryInternal.swift using the existing @_spi(Private) bridge.

💚 How did you test it?

5 unit tests in test/tracing/nativeScopeSync.test.ts: root span sync, child span skip, SentryNonRecordingSpan skip, sampled/sampleRand propagation, per-span firing.
Full test suite: 1718 tests pass.

📝 Checklist

I added tests to verify changes.
No new PII added or SDK only sends newly added PII if sendDefaultPII is enabled.
I updated the docs if needed.
I updated the wizard if needed.
All tests passing.
Public API changes reviewed by another Mobile SDK team member or implemented according to the develop docs spec.
No breaking changes.

🔮 Next steps

DSC/baggage propagation and iOS sampled flag — SentrySDK.internal.setTrace sets traceId+spanId only; follow up with sentry-cocoa once the API is extended.

When a new JS root span starts, push its traceId, spanId, sampled, and sampleRand to the native SDK scope via a new bridge method. Native HTTP instrumentation (OkHttp on Android, URLSession on iOS) then attaches the correct sentry-trace header, linking native spans to the JS trace. Fixes #6237 Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

github-actions · 2026-09-08T12:30:58Z

Semver Impact of This PR

⚪ None (no version bump detected)

📋 Changelog Preview

This is how your changes will appear in the changelog.
Entries from this PR are highlighted with a left border (blockquote style).

feat(tracing): sync JS scope propagation context to native scope by alwx in #6686

fix(android): identify the screen appear event by name instead of class by TaduJR in #6692
chore(deps): update Android SDK to v8.56.0 by github-actions in #6694
ci: reduce sample app build matrix to production-only by alwx in #6687
chore(deps): update JavaScript SDK to v10.74.0 by github-actions in #6695
chore(deps): update Cocoa SDK to v9.28.0 by github-actions in #6693
test(e2e): Evaluate replay assertion on Android by antonis in #6684
test(e2e): Restore iOS replay assertion in captureReplay test by antonis in #6683
feat(visionos): Add visionOS sample app by antonis in #6676
fix(core): Align beforeBreadcrumb and tracesSampler error fallbacks with spec by antonis in #6675
chore(replay): Mark mobileReplayIntegration as stable by antonis in #6679
feat(sample): Add tvOS sample app by antonis in #6677
fix(e2e): Pin json gem < 3.0 for RN < 0.72 iOS builds by antonis in #6678
feat(ios): Expose enableMemoryIntrospection option by antonis in #6674
feat(android): Add anrProfilingSampleRate option by antonis in #6673
ci: Unpin Android E2E emulator build by antonis in #6672
ref(ios): Remove deprecated private SDK API usage by philprime in #6647
chore(deps): update Cocoa SDK to v9.27.0 by github-actions in #6670
chore(deps): update Sentry Android Gradle Plugin to v6.21.0 by github-actions in #6671
chore(deps): Bump fast-uri to ^3.1.6 to resolve security alerts by antonis in #6662
chore(deps): Bump qs to ^6.16.0 to resolve security alerts by antonis in #6663
chore(deps): Bump @xmldom/xmldom pins to patched versions to resolve security alerts by antonis in #6664
docs: Revamp root and nested AGENTS.md by antonis in #6666

_{🤖 This preview updates automatically when you update the PR.}

github-actions · 2026-09-08T12:31:13Z

	Messages
📖	Do not forget to update Sentry-docs with your feature once the pull request gets approved.

Generated by 🚫 dangerJS against dbcdc7d

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

cursor

Stale Bugbot comment from a previous run.

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

@ReactMethod

…ridge modules - Add missing @ReactMethod wrapper in oldarch RNSentryModule - Add missing @OverRide wrapper in newarch RNSentryModule - Guard against null ctx/traceId/spanId in RNSentryModuleImpl - Pass null instead of sampled boolean as sample rate; the Java SDK expects the actual configured rate (0.0–1.0), not a boolean flag Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

- Update native context for all root spans including non-recording (unsampled) ones to prevent stale traceId lingering from a previous navigation - Make setCurrentScopePropagationContext synchronous on iOS (RCT_EXPORT_SYNCHRONOUS_TYPED_METHOD) and Android (boolean return) to eliminate race with native URLSession/OkHttp - Update NativeRNSentry spec return type void→boolean to match synchronous codegen path - Document that iOS setTrace does not accept sampled/sampleRand (Cocoa SDK limitation) Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

cursor

Cursor Bugbot has reviewed your changes and found 1 potential issue.

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^{Reviewed by Cursor Bugbot for commit ae93384. Configure here.}

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

…ive scope sync - RNSentryInternal: reformat 32-char hex traceId to hyphenated UUID before passing to SentryId(uuidString:); without hyphens it silently produces an empty SentryId and trace linking breaks on iOS. - syncPropagationContextToNative: skip root spans that are not the active span so inactive forceTransaction roots (app start, expo-updates) do not clobber the native propagation context of an in-flight navigation span. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

…sync - span.ts: revert getActiveSpan() guard — spanStart fires before idle spans are made active, so the guard was skipping every navigation span and the feature never synced. All root spans now trigger a sync; the JSDoc explains the timing constraint. - RNSentryModuleImpl: read the JS `sampled` boolean and apply it via PropagationContext.setSampled() so OkHttp spans carry the correct isSampled decision, not just sampleRand. Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

sentry · 2026-09-10T07:50:13Z

+    const ctx = span.spanContext();
+    const propagationCtx = getCurrentScope().getPropagationContext();
+    NATIVE.setCurrentScopePropagationContext({
+      traceId: ctx.traceId,
+      spanId: ctx.spanId,
+      sampled: spanIsSampled(span),
+      sampleRand: propagationCtx.sampleRand ?? Math.random(),


Bug: Root spans created without startIdleSpan can cause a mismatched propagation context, combining a new traceId with a stale sampleRand, leading to incorrect native sampling.
_{Severity: MEDIUM}

Suggested Fix

Ensure that code paths creating root spans, like startInactiveSpan({ forceTransaction: true }), explicitly update the propagation context with a new traceId and sampleRand before the span starts, similar to how startIdleSpan does. This will prevent syncPropagationContextToNative from using stale data.

Prompt for AI Agent

Review the code at the location below. A potential bug has been identified by an AI agent. Verify if this is a real issue. If it is, propose a fix; if not, explain why it's not valid. Location: packages/core/src/js/tracing/span.ts#L223-L229 Potential issue: For root spans not created via `startIdleSpan`, such as those for app-start using `startInactiveSpan({ forceTransaction: true })`, the native scope synchronization logic can create a mismatched propagation context. When `syncPropagationContextToNative` is triggered, it uses the `traceId` from the new span but may use a stale `sampleRand` value from the previous trace's scope. This sends a mismatched context to the native layer, potentially causing incorrect sampling decisions for downstream native HTTP calls.

This looks valid 👍
Also these background roots come from startInactiveSpan({ forceTransaction: true }) (appStart.ts:556/1019, expoupdateslistener.ts:207/224) and can start mid navigation, overwriting the native trace that in-flight native HTTP spans link to, with no restore when they end. Refreshing their propagation context (the suggested fix) keeps the pushed values consistent but still links native calls to the wrong trace.

The right fix would be to skip background/inactive roots (those created via startInactiveSpan that never become the active span). But distinguishing those from navigation roots at spanStart time is tricky so I will rather create a follow-up issue.

Sounds good 👍 Thank you 🙇

antonis · 2026-09-10T08:25:45Z

  }

-  @ReactMethod
+  @ReactMethod(isBlockingSynchronousMethod = true)


q: Why do we change this? I think it might degrade the performance

github-actions · 2026-09-10T08:31:23Z

Android (legacy) Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	485.26 ms	536.90 ms	51.63 ms
Size	50.56 MiB	56.47 MiB	5.91 MiB

Baseline results on branch: main

Startup times

Revision	Plain	With Sentry	Diff
`ae37560`+dirty	470.40 ms	564.12 ms	93.72 ms
`40c9884`+dirty	430.40 ms	497.76 ms	67.36 ms
`7ff4d0f`+dirty	413.81 ms	450.64 ms	36.83 ms
`580fb5c`+dirty	436.34 ms	471.63 ms	35.28 ms
`a5d243c`+dirty	424.52 ms	485.18 ms	60.66 ms
`4b87b12`+dirty	421.82 ms	413.60 ms	-8.22 ms
`bc8f61e`+dirty	442.98 ms	506.56 ms	63.58 ms
`774257e`+dirty	407.09 ms	447.46 ms	40.37 ms
`5257d80`+dirty	423.37 ms	467.54 ms	44.17 ms
`3817909`+dirty	406.67 ms	416.58 ms	9.91 ms

App size

Revision	Plain	With Sentry	Diff
`ae37560`+dirty	48.30 MiB	53.60 MiB	5.29 MiB
`40c9884`+dirty	49.74 MiB	55.09 MiB	5.34 MiB
`7ff4d0f`+dirty	48.30 MiB	53.60 MiB	5.30 MiB
`580fb5c`+dirty	49.74 MiB	54.79 MiB	5.05 MiB
`a5d243c`+dirty	48.30 MiB	53.54 MiB	5.23 MiB
`4b87b12`+dirty	43.75 MiB	48.14 MiB	4.39 MiB
`bc8f61e`+dirty	49.74 MiB	55.09 MiB	5.35 MiB
`774257e`+dirty	48.30 MiB	53.58 MiB	5.28 MiB
`5257d80`+dirty	48.30 MiB	53.58 MiB	5.28 MiB
`3817909`+dirty	43.75 MiB	48.08 MiB	4.33 MiB

sentry · 2026-09-10T08:32:35Z

📲 Install Builds

Android

🔗 App Name	App ID	Version	Configuration
Sentry RN	io.sentry.reactnative.sample	8.25.0 (105)	Release

⚙️ sentry-react-native Build Distribution Settings

github-actions · 2026-09-10T08:32:41Z

iOS (legacy) Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	3850.53 ms	1215.11 ms	-2635.42 ms
Size	5.15 MiB	6.89 MiB	1.74 MiB

Baseline results on branch: main

Startup times

Revision	Plain	With Sentry	Diff
`d200634`+dirty	3829.38 ms	1224.08 ms	-2605.30 ms
`3b6e9f9`+dirty	3851.90 ms	1233.33 ms	-2618.57 ms
`4e0b819`+dirty	3839.05 ms	1210.75 ms	-2628.30 ms
`1e5d96d`+dirty	3851.45 ms	1212.05 ms	-2639.41 ms
`0a9e622`+dirty	3835.87 ms	1221.07 ms	-2614.80 ms
`7ac3378`+dirty	1213.37 ms	1218.15 ms	4.78 ms
`9ad4522`+dirty	3850.40 ms	1222.40 ms	-2628.00 ms
`20fbd51`+dirty	3827.47 ms	1213.32 ms	-2614.15 ms
`d0e3b3e`+dirty	3854.77 ms	1218.58 ms	-2636.19 ms
`822d35b`+dirty	3830.64 ms	1209.20 ms	-2621.44 ms

App size

Revision	Plain	With Sentry	Diff
`d200634`+dirty	5.15 MiB	6.89 MiB	1.74 MiB
`3b6e9f9`+dirty	5.15 MiB	6.68 MiB	1.53 MiB
`4e0b819`+dirty	4.98 MiB	6.46 MiB	1.49 MiB
`1e5d96d`+dirty	4.98 MiB	6.46 MiB	1.49 MiB
`0a9e622`+dirty	4.98 MiB	6.51 MiB	1.53 MiB
`7ac3378`+dirty	3.38 MiB	4.76 MiB	1.38 MiB
`9ad4522`+dirty	4.98 MiB	6.56 MiB	1.58 MiB
`20fbd51`+dirty	4.98 MiB	6.46 MiB	1.49 MiB
`d0e3b3e`+dirty	4.98 MiB	6.51 MiB	1.53 MiB
`822d35b`+dirty	4.98 MiB	6.50 MiB	1.53 MiB

github-actions · 2026-09-10T08:44:12Z

iOS (new) Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	3862.89 ms	1238.78 ms	-2624.12 ms
Size	5.15 MiB	6.89 MiB	1.74 MiB

Baseline results on branch: main

Startup times

Revision	Plain	With Sentry	Diff
`68ae91b`+dirty	3836.36 ms	1222.04 ms	-2614.32 ms
`0b5a379`+dirty	3857.69 ms	1230.34 ms	-2627.35 ms
`bf168a4`+dirty	3846.83 ms	1221.33 ms	-2625.49 ms
`f170ec3`+dirty	3844.74 ms	1222.67 ms	-2622.07 ms
`68672fc`+dirty	3832.22 ms	1228.29 ms	-2603.93 ms
`84cba31`+dirty	3830.40 ms	1204.44 ms	-2625.96 ms
`2c735cc`+dirty	1223.33 ms	1224.38 ms	1.04 ms
`b9bebee`+dirty	3858.02 ms	1231.92 ms	-2626.11 ms
`a50b33d`+dirty	1207.11 ms	1212.10 ms	5.00 ms
`5569641`+dirty	3824.35 ms	1210.78 ms	-2613.57 ms

App size

Revision	Plain	With Sentry	Diff
`68ae91b`+dirty	4.98 MiB	6.46 MiB	1.48 MiB
`0b5a379`+dirty	5.15 MiB	6.70 MiB	1.54 MiB
`bf168a4`+dirty	4.98 MiB	6.47 MiB	1.49 MiB
`f170ec3`+dirty	5.15 MiB	6.69 MiB	1.53 MiB
`68672fc`+dirty	5.15 MiB	6.71 MiB	1.55 MiB
`84cba31`+dirty	4.98 MiB	6.55 MiB	1.57 MiB
`2c735cc`+dirty	3.38 MiB	4.74 MiB	1.35 MiB
`b9bebee`+dirty	5.15 MiB	6.68 MiB	1.53 MiB
`a50b33d`+dirty	3.38 MiB	4.73 MiB	1.35 MiB
`5569641`+dirty	5.15 MiB	6.67 MiB	1.51 MiB

antonis

Left a couple of comments that should be checked but nothing blocking on my side 👍

github-actions · 2026-09-10T09:02:34Z

Android (new) Performance metrics 🚀

	Plain	With Sentry	Diff
Startup time	426.06 ms	431.41 ms	5.35 ms
Size	50.56 MiB	56.47 MiB	5.91 MiB

Baseline results on branch: main

Startup times

Revision	Plain	With Sentry	Diff
`f3215d3`+dirty	396.53 ms	436.66 ms	40.13 ms
`d0e3b3e`+dirty	443.19 ms	480.00 ms	36.81 ms
`a5d243c`+dirty	499.20 ms	525.62 ms	26.42 ms
`7fd0012`+dirty	422.41 ms	445.57 ms	23.17 ms
`0a147b2`+dirty	442.80 ms	522.24 ms	79.44 ms
`d7d54c6`+dirty	423.54 ms	498.56 ms	75.02 ms
`c823bb5`+dirty	468.26 ms	516.16 ms	47.90 ms
`5789645`+dirty	502.66 ms	594.19 ms	91.53 ms
`40c9884`+dirty	453.76 ms	478.98 ms	25.22 ms
`d771cd5`+dirty	432.29 ms	464.38 ms	32.09 ms

App size

Revision	Plain	With Sentry	Diff
`f3215d3`+dirty	48.30 MiB	53.49 MiB	5.19 MiB
`d0e3b3e`+dirty	49.74 MiB	55.09 MiB	5.34 MiB
`a5d243c`+dirty	48.30 MiB	53.54 MiB	5.23 MiB
`7fd0012`+dirty	50.56 MiB	56.46 MiB	5.90 MiB
`0a147b2`+dirty	49.74 MiB	55.08 MiB	5.34 MiB
`d7d54c6`+dirty	49.74 MiB	55.09 MiB	5.34 MiB
`c823bb5`+dirty	48.30 MiB	53.58 MiB	5.28 MiB
`5789645`+dirty	49.74 MiB	54.85 MiB	5.11 MiB
`40c9884`+dirty	49.74 MiB	55.09 MiB	5.34 MiB
`d771cd5`+dirty	49.74 MiB	55.36 MiB	5.62 MiB

JS callers declare it void and never use the return value, so blocking the JS thread was unnecessary overhead.

alwx and others added 2 commits September 8, 2026 14:42

docs: add changelog entry for native scope propagation context sync

b452c98

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

chore: merge main into alwx/feature/scope-propagation

2fe54fd

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

alwx marked this pull request as ready for review September 8, 2026 12:45

alwx requested review from antonis and lucas-zimerman as code owners September 8, 2026 12:45

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Comment thread packages/core/src/js/tracing/span.ts

fix(lint): remove unused Span import in nativeScopeSync test

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fix(lint): apply clang-format to RNSentry.mm and update API report

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fix(android): revert setActiveSpanId to async on old arch

dbcdc7d

JS callers declare it void and never use the return value, so blocking the JS thread was unnecessary overhead.

alwx mentioned this pull request Sep 10, 2026

fix(tracing): background root spans overwrite native propagation context #6697

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alwx merged commit 60ad791 into main Sep 10, 2026
71 of 83 checks passed

alwx deleted the alwx/feature/scope-propagation branch September 10, 2026 10:26

sentry-release-bot Bot mentioned this pull request Sep 10, 2026

publish: getsentry/sentry-react-native@8.26.0 getsentry/publish#9484

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github-actions Bot mentioned this pull request Sep 10, 2026

Sync JS scope propagation context to native scope (link native spans to JS trace) #6237

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alwx commented Sep 8, 2026

📢 Type of change

📜 Description

💡 Motivation and Context

💚 How did you test it?

📝 Checklist

🔮 Next steps

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github-actions Bot commented Sep 10, 2026

Android (legacy) Performance metrics 🚀

Baseline results on branch: main

Startup times

App size

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📲 Install Builds

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iOS (legacy) Performance metrics 🚀

Baseline results on branch: main

Startup times

App size

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iOS (new) Performance metrics 🚀

Baseline results on branch: main

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