feat: Streamline isolation scope handling & reset in isolation scopes by mydea · Pull Request #22890 · getsentry/sentry-javascript

mydea · 2026-07-31T07:19:51Z

This PR does two things:

Removes any usage of propagation context on isolation scope. We never really need/read this, as the current scope one will always overwrite this. Generally we should only ever set/read propagation context on current scope.
Adjust server-side withIsolationScope to reset the propagation context unless it is continuing a trace. Today, this kind of works in otel-based places because we wrap root spans in startNewTrace. But this does not align with core/browser handling, so going forward this will be removed. instead, we want this logic to be applied in an isolation scope, so the following code will result in separate traces:

Sentry.withIsolationScope(() => {
  Sentry.startSpan({ name: 'process 1' }, () => ...);
});

Sentry.withIsolationScope(() => {
  Sentry.startSpan({ name: 'process 2' }, () => ...);
});

without this change, both of these spans would be part of the same trace, which is not what we want in server.

note: In browser, we do not actually fork the isolation scope, there is just a single one, so this does not apply.

github-actions · 2026-07-31T07:27:41Z

size-limit report 📦

Path	Size	% Change	Change
@sentry/browser	29.91 kB	-	-
@sentry/browser - with treeshaking flags	28.11 kB	-	-
@sentry/browser (incl. Tracing)	47.35 kB	-0.05%	-22 B 🔽
@sentry/browser (incl. Tracing + Span Streaming)	47.36 kB	-0.05%	-22 B 🔽
@sentry/browser (incl. Tracing, Profiling)	52.13 kB	-0.04%	-18 B 🔽
@sentry/browser (incl. Tracing, Replay)	86.69 kB	-0.03%	-21 B 🔽
@sentry/browser (incl. Tracing, Replay) - with treeshaking flags	76.13 kB	-0.03%	-18 B 🔽
@sentry/browser (incl. Tracing, Replay with Canvas)	91.41 kB	-0.02%	-18 B 🔽
@sentry/browser (incl. Tracing, Replay, Feedback)	104.05 kB	-0.02%	-18 B 🔽
@sentry/browser (incl. Feedback)	47.22 kB	-	-
@sentry/browser (incl. sendFeedback)	34.76 kB	-	-
@sentry/browser (incl. FeedbackAsync)	39.86 kB	-	-
@sentry/browser (incl. Metrics)	30.99 kB	-	-
@sentry/browser (incl. Logs)	31.22 kB	-	-
@sentry/browser (incl. Metrics & Logs)	31.89 kB	-	-
@sentry/react	31.73 kB	-	-
@sentry/react (incl. Tracing)	49.61 kB	-0.07%	-32 B 🔽
@sentry/vue	34.98 kB	-0.03%	-9 B 🔽
@sentry/vue (incl. Tracing)	49.34 kB	-0.05%	-20 B 🔽
@sentry/svelte	29.94 kB	-	-
CDN Bundle	31.98 kB	-	-
CDN Bundle (incl. Tracing)	47.72 kB	-0.04%	-19 B 🔽
CDN Bundle (incl. Logs, Metrics)	33.55 kB	-	-
CDN Bundle (incl. Tracing, Logs, Metrics)	49.07 kB	-0.04%	-17 B 🔽
CDN Bundle (incl. Replay, Logs, Metrics)	72.9 kB	-	-
CDN Bundle (incl. Tracing, Replay)	85.34 kB	-0.03%	-18 B 🔽
CDN Bundle (incl. Tracing, Replay, Logs, Metrics)	86.64 kB	-0.03%	-19 B 🔽
CDN Bundle (incl. Tracing, Replay, Feedback)	91.13 kB	-0.03%	-22 B 🔽
CDN Bundle (incl. Tracing, Replay, Feedback, Logs, Metrics)	92.44 kB	-0.03%	-23 B 🔽
CDN Bundle - uncompressed	95.49 kB	-	-
CDN Bundle (incl. Tracing) - uncompressed	143.08 kB	-0.12%	-171 B 🔽
CDN Bundle (incl. Logs, Metrics) - uncompressed	100.2 kB	-	-
CDN Bundle (incl. Tracing, Logs, Metrics) - uncompressed	147.06 kB	-0.12%	-171 B 🔽
CDN Bundle (incl. Replay, Logs, Metrics) - uncompressed	224.96 kB	-	-
CDN Bundle (incl. Tracing, Replay) - uncompressed	262.34 kB	-0.07%	-171 B 🔽
CDN Bundle (incl. Tracing, Replay, Logs, Metrics) - uncompressed	266.3 kB	-0.07%	-171 B 🔽
CDN Bundle (incl. Tracing, Replay, Feedback) - uncompressed	276.04 kB	-0.07%	-171 B 🔽
CDN Bundle (incl. Tracing, Replay, Feedback, Logs, Metrics) - uncompressed	280 kB	-0.07%	-171 B 🔽
@sentry/nextjs (client)	52.2 kB	-0.03%	-11 B 🔽
@sentry/sveltekit (client)	47.8 kB	-0.04%	-17 B 🔽
@sentry/core/server	80 kB	+0.02%	+8 B 🔺
@sentry/core/browser	51.96 kB	+0.08%	+37 B 🔺
@sentry/node	121.89 kB	+0.04%	+39 B 🔺
@sentry/node/import (ESM hook with diagnostics-channel injection)	0 B	added	added
@sentry/node - without tracing	85.36 kB	+0.06%	+48 B 🔺
@sentry/aws-serverless	94.01 kB	+0.06%	+54 B 🔺
@sentry/cloudflare (withSentry) - minified	199.28 kB	+0.05%	+90 B 🔺
@sentry/cloudflare (withSentry)	490.77 kB	+0.05%	+213 B 🔺

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Lms24

I think this is a good change!

Lms24 · 2026-07-31T08:33:31Z


  if (!hasSpansEnabled()) {
-    const scopePropagationContext = { ...isolationScope.getPropagationContext(), ...scope.getPropagationContext() };
+    const scopePropagationContext = scope.getPropagationContext();


it seems like this removes a footgun where we potentially incorrectly merged a propagation context before here. I like it!

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There was still a missed case where the isolation scop's propagation context was (now incorrectly) being used. Test verifies the resulting mismatched behavior.

isaacs

This is a good change, but there are a few gaps, which I think would result in bugs in trace propagation.

I rebased it onto develop, which picked up the fix for one missing case, which was fixed on 46f7431 as part of #22889.

For the others, I added commits with tests and fixes here: https://gist.github.com/isaacs/790e2d23abeebddf5b9079f53e4fbf45 or on the isaacs/fix-fn/streamline-acs-isolation-scope branch.

I figured this is probably more useful than just comments, since I'm going to be out next 2 weeks, so whoever picks this up can inspect and land with those additions, or go a different direction if you decide. 👍

isaacs · 2026-07-31T23:34:36Z

Should this also be updated to just scope.getPropagationContext()?

Suggested change

} = scope.getPropagationContext();

or:

Suggested change

} = {

...scope.getPropagationContext(),

};

cursor Bot reviewed Jul 31, 2026

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Comment thread packages/server-utils/src/async-context.ts

mydea force-pushed the fn/streamline-acs-isolation-scope branch from 2cab26a to 1eda574 Compare July 31, 2026 07:32

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Comment thread packages/server-utils/src/async-context.ts

Comment thread packages/server-utils/test/async-context.test.ts

mydea force-pushed the fn/streamline-acs-isolation-scope branch from 1eda574 to ccf3b05 Compare July 31, 2026 07:57

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Comment thread packages/server-utils/src/async-context.ts

Comment thread packages/server-utils/src/async-context.ts

mydea force-pushed the fn/streamline-acs-isolation-scope branch from ccf3b05 to 8979856 Compare July 31, 2026 08:15

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mydea force-pushed the fn/streamline-acs-isolation-scope branch from 8979856 to 8196869 Compare July 31, 2026 08:46

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Comment thread packages/core/src/exports.ts Outdated

mydea force-pushed the fn/streamline-acs-isolation-scope branch from a2496b8 to 7e8cef9 Compare July 31, 2026 09:07

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Comment thread packages/core/src/monitor.ts Outdated

mydea force-pushed the fn/streamline-acs-isolation-scope branch from 7e8cef9 to dea8d51 Compare July 31, 2026 09:32

mydea force-pushed the fn/streamline-acs-isolation-scope branch from dea8d51 to d1f9cac Compare July 31, 2026 09:39

mydea force-pushed the fn/streamline-acs-isolation-scope branch from d1f9cac to 2efb184 Compare July 31, 2026 10:10

mydea marked this pull request as ready for review July 31, 2026 10:21

mydea requested review from a team as code owners July 31, 2026 10:21

mydea requested review from JPeer264, isaacs, logaretm and msonnb and removed request for a team July 31, 2026 10:21

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Comment thread packages/core/src/monitor.ts

Base automatically changed from fn/acs-server-utils to develop July 31, 2026 18:41

mydea and others added 6 commits July 31, 2026 16:52

feat: Streamline isolation scope handling & reset in isolation scopes

1aecbfa

monitor change

d01ded9

fix: remove remaining getIsolationScope propagation context

d2d0d34

There was still a missed case where the isolation scop's propagation context was (now incorrectly) being used. Test verifies the resulting mismatched behavior.

fix: prevent carrying old context into new trace

e3528d3

fix: detect continuation of a trace based on propagationSpanId or dsc

b6e8f43

fix(core): do not share monitor scope's context with parent

867164f

isaacs force-pushed the fn/streamline-acs-isolation-scope branch from 65c8a4c to d01ded9 Compare August 1, 2026 00:30

isaacs reviewed Aug 1, 2026

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Gate the monitor trace restore on isContinuingTrace

f90718e

andreiborza approved these changes Aug 3, 2026

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andreiborza merged commit ae3de33 into develop Aug 3, 2026
514 of 518 checks passed

andreiborza deleted the fn/streamline-acs-isolation-scope branch August 3, 2026 09:35

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feat: Streamline isolation scope handling & reset in isolation scopes - #22890

feat: Streamline isolation scope handling & reset in isolation scopes#22890
andreiborza merged 7 commits into
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fn/streamline-acs-isolation-scope

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+} = {
+  ...scope.getPropagationContext(),
+};

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github-actions Bot commented Jul 31, 2026 •

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