chore(contexts): Remove default-trace-ID option by thetruecpaul · Pull Request #5979 · getsentry/relay

thetruecpaul · 2026-05-11T22:08:55Z

Shipped this a week ago and have seen no problems. 👍

shashjar · 2026-05-11T22:43:33Z

        // If the event lacks a TraceContext, add a random one.

-        if config.derive_trace_id && !contexts.contains::<TraceContext>() {
+        if !contexts.contains::<TraceContext>() {


raised discussion about this in Slack: https://sentry.slack.com/archives/C09QBCVRCAU/p1778539337468769

That's a good catch, also replied to it on Slack.

tldr; the SchemaProcessor will remove the TraceContext if the trace_id is missing. To not be order dependent, you probably always want to create the context and insert a trace id if it is missing.

As an example: If an SDK sends an invalid trace id, it may be empty, but with metadata attached that there was an invalid trace id.

This comes back to a previous discussion, where it would be better if the downstream consumers gracefully handle missing trace ids.

Dav1dde

Thanks, for coming back and cleaning this up.

You accidentally updated/reverted the submodules, sentry-conventions and sentry-native. You might be missing a git submodule update --recursive --init.

Dav1dde · 2026-05-12T08:32:37Z

        // If the event lacks a TraceContext, add a random one.

-        if config.derive_trace_id && !contexts.contains::<TraceContext>() {
+        if !contexts.contains::<TraceContext>() {


That's a good catch, also replied to it on Slack.

tldr; the SchemaProcessor will remove the TraceContext if the trace_id is missing. To not be order dependent, you probably always want to create the context and insert a trace id if it is missing.

As an example: If an SDK sends an invalid trace id, it may be empty, but with metadata attached that there was an invalid trace id.

This comes back to a previous discussion, where it would be better if the downstream consumers gracefully handle missing trace ids.

Dav1dde · 2026-05-12T08:33:22Z

 - Bump `sentry-conventions` to 0.6.0-4. ([#5944](https://github.com/getsentry/relay/pull/5944))
 - Enable compression for forwarded uploads. ([#5965](https://github.com/getsentry/relay/pull/5965))
 - Change the default partitioning for the envelope buffer from semantic to round-robin. ([#5967](https://github.com/getsentry/relay/pull/5967))
+- Remove option gating default-trace-ID behavior. ([#5979](https://github.com/getsentry/relay/pull/5979))


Suggested change

- Remove option gating default-trace-ID behavior. ([#5979](https://github.com/getsentry/relay/pull/5979))

- Unconditionally create a trace context with a trace id for errors. ([#5979](https://github.com/getsentry/relay/pull/5979))

I'd phrase it more to what effect the change has on users/downstream consumers.

I chose to focus on the removal of the option, rather than the trace context / trace ID, because the option has already been launched to 100% — so there should be no effect on users/downstream consumers.

That said, this is your repo — I'll defer to your suggestion. :-)

thetruecpaul · 2026-05-12T21:04:54Z

+        if !contexts.contains::<TraceContext>()
+            || contexts
+                .get_or_default::<TraceContext>()
+                .trace_id
+                .0
+                .is_none()
+        {


See changes

shashjar · 2026-05-12T21:10:08Z

+                .0
+                .is_none()
+        {
            contexts.add(TraceContext::random(event_id))


If there's a TraceContext with valid information but it's missing trace_id (not sure if this actually occurs in practice) - I think we'll end up overriding the entire context with a new one that has only trace_id? I think we want to get_or_default the trace context, then check whether trace_context.trace_id is null, and then set only trace_context.trace_id if so

shashjar · 2026-05-12T21:10:25Z

        // If the event lacks a TraceContext, add a random one.

-        if config.derive_trace_id && !contexts.contains::<TraceContext>() {
+        if !contexts.contains::<TraceContext>()


Can we add unit tests for this logic somewhere?

Updating the tests is what I'm working on now! :-)

Just a drive by comment before bed, an integration test (if it doesn't already exist) would be great, we do have a decent framework for them and they work great for regression tests.

cursor

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

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^{Reviewed by Cursor Bugbot for commit 9942b0b. Configure here.}

cursor · 2026-05-12T23:32:07Z

+            let trace_ctx = contexts.get_or_default::<TraceContext>();
+            if trace_ctx.trace_id.0.is_none() {
+                trace_ctx.trace_id = Annotated::new(TraceId::random())
+            }


Inconsistent trace ID derivation between if/else branches

Medium Severity

When no TraceContext exists, TraceContext::random(event_id) derives the trace ID deterministically from the event_id (using TraceId::from(event_id)) and attaches a trace_id.missing remark. But when a TraceContext exists with a missing trace_id, the else branch uses TraceId::random() which generates a truly random UUID via Uuid::new_v4() and attaches no remark. This means the trace ID strategy differs depending on whether an SDK sent an empty TraceContext or none at all, and the provenance metadata is lost in the else case.

^{Reviewed by Cursor Bugbot for commit 9942b0b. Configure here.}

Dav1dde · 2026-05-13T06:30:35Z

        // If the event lacks a TraceContext, add a random one.

-        if config.derive_trace_id && !contexts.contains::<TraceContext>() {
+        if !contexts.contains::<TraceContext>() {


You can unify the branches with let trace_ctx = contexts.get_or_default::<TraceContext>()

thetruecpaul requested a review from a team May 11, 2026 22:08

thetruecpaul requested a review from a team as a code owner May 11, 2026 22:08

thetruecpaul force-pushed the cpaul/051126/ship-default-trace-id branch from 04f1690 to a55366d Compare May 11, 2026 22:12

shashjar approved these changes May 11, 2026

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Dav1dde requested changes May 12, 2026

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thetruecpaul force-pushed the cpaul/051126/ship-default-trace-id branch 2 times, most recently from 274748d to 4654bdc Compare May 12, 2026 17:50

cursor Bot reviewed May 12, 2026

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Comment thread relay-event-normalization/src/event.rs

thetruecpaul force-pushed the cpaul/051126/ship-default-trace-id branch from 4654bdc to de252d4 Compare May 12, 2026 19:38

sentry Bot reviewed May 12, 2026

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Comment thread relay-event-normalization/src/event.rs Outdated

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Comment thread relay-event-normalization/src/event.rs Outdated

thetruecpaul commented May 12, 2026

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shashjar reviewed May 12, 2026

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chore(contexts): Remove default-trace-ID option

9942b0b

thetruecpaul force-pushed the cpaul/051126/ship-default-trace-id branch from de252d4 to 9942b0b Compare May 12, 2026 23:27

cursor Bot reviewed May 12, 2026

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Dav1dde reviewed May 13, 2026

View reviewed changes

	- Remove option gating default-trace-ID behavior. ([#5979](https://github.com/getsentry/relay/pull/5979))
	- Unconditionally create a trace context with a trace id for errors. ([#5979](https://github.com/getsentry/relay/pull/5979))

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thetruecpaul commented May 11, 2026

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shashjar May 12, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Inconsistent trace ID derivation between if/else branches

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shashjar May 12, 2026 •

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