[SDT-0002]: move ServiceContext from SSC to SDT implementation by kukushechkin · Pull Request #240 · apple/swift-distributed-tracing

kukushechkin · 2026-09-09T14:59:26Z

Move ServiceContext from swift-service-context as Instrumentation.InstrumentationContext. Implements SDT-0002, companion to apple/swift-service-context#92.

Motivation:

ServiceContext lived in its own package mainly for swift-distributed-tracing users, adding release overhead for little benefit. The name also reads as server-specific, discouraging non-server adoption.

Modifications:

Moved ServiceContext to Instrumentation.
Renamed ServiceContext/ServiceContextKey/AnyServiceContextKey to InstrumentationContext/InstrumentationContextKey/AnyInstrumentationContextKey, keeping deprecated typealiases for old symbols.

Result:

Existing code keeps compiling unchanged. Direct dependents using the old names get a deprecation warning with a fix-it; swift-service-context dependents get none, by design.

diagnose-api-breaking-changes reports breaking changes across Tracing/Instrumentation/InMemoryTracing, all "type changed to Instrumentation.InstrumentationContext". This is expected — typealiases are transparent to the type system, so this shows up no matter which name call sites use, and we don't target ABI stability here, only source-compatibility.

czechboy0

Did we consider putting the new types into one of the existing modules? Why do we want it in a separate one?

heckj · 2026-09-24T16:54:35Z

@kukushechkin would you mind tacking on ContextStorage to the .spi.yaml as well, so that this module is included in SPI's documentation rendering.

diff --git a/.spi.yml b/.spi.yml
index 26f45b2..ea570cd 100644
--- a/.spi.yml
+++ b/.spi.yml
@@ -1,4 +1,4 @@
 version: 1
 builder:
   configs:
-    - documentation_targets: [Tracing, Instrumentation, InMemoryTracing]
+    - documentation_targets: [Tracing, Instrumentation, InMemoryTracing, ContextStorage]

Co-authored-by: Joseph Heck <j_heck@apple.com>

kukushechkin · 2026-09-25T11:51:29Z

Did we consider putting the new types into one of the existing modules? Why do we want it in a separate one?

@czechboy0 no, did not think about it. It feels it should be in a separate module. What is the downside of have a new module?

czechboy0 · 2026-09-25T12:59:24Z

Did we consider putting the new types into one of the existing modules? Why do we want it in a separate one?

@czechboy0 no, did not think about it. It feels it should be in a separate module. What is the downside of have a new module?

I feel that the default should be not to separate into a separate module, unless we have a good reason. Do we?

slashmo · 2026-09-25T13:04:20Z

Did we consider putting the new types into one of the existing modules? Why do we want it in a separate one?

I agree with Honza to put it in Tracing given it's now called TracingContext. If we change our mind down the line it's easy to split out TracingContext into a new target using exported imports. However, moving from two targets back to one is a bit more complex. I'd lean towards not adding the separate target unless we have a use-case outside the Tracing target.

kukushechkin · 2026-09-25T13:06:03Z

@czechboy0 @slashmo Tracing <-> TracingContext, I see the point. Will do.

UPD. Ah, wait, no, Instrumentation depends on ContextStorage. And Tracing depends on Instrumentation. Moving TracingContext to Tracing will create a circular dependency.

slashmo · 2026-09-25T13:14:46Z

Hm, yeah. We need it for the context propagation requirement of Instrument. In that case I'd put it in Instrumentation directly rather than ContextStorage. That being said, should it be called InstrumentationContext instead of TracingContext then?

kukushechkin · 2026-09-25T13:22:52Z

Hm, yeah. We need it for the context propagation requirement of Instrument. In that case I'd put it in Instrumentation directly rather than ContextStorage. That being said, should it be called InstrumentationContext instead of TracingContext then?

Also works. @czechboy0 wdyt?

czechboy0 · 2026-09-25T20:53:53Z

Works for me.

ktoso · 2026-09-28T19:57:09Z

Sounds fine to me, while keeping a typealias for compatibility I guess right?

czechboy0

One last docs fix, otherwise lgtm

Co-authored-by: Honza Dvorsky <honza@apple.com>

…tion (#92) Turn this package into a thin compatibility layer over swift-distributed-tracing. ## Motivation: Companion to apple/swift-distributed-tracing#240. `ServiceContext`'s implementation moved there, renamed to `TracingContext`. This package now re-exports it instead of owning it. ## Modifications: - Added a dependency on swift-distributed-tracing. - `ServiceContextModule` re-exports its `ContextStorage` module and declares its own non-deprecated `ServiceContext`/`ServiceContextKey`/`AnyServiceContextKey` typealiases. - Moved the behavior test suite to swift-distributed-tracing. - Add a compatibility smoke test. - Updated the README to point new adopters at swift-distributed-tracing directly. ## Result: `import ServiceContextModule` keeps working with no code changes and no deprecation warning, even in a file that also imports `Tracing` directly. New code should depend on swift-distributed-tracing and use `TracingContext` instead.

### Motivation `swift-distributed-tracing` 1.6.0 moved `ServiceContext` into its `Instrumentation` module and renamed it `InstrumentationContext` (apple/swift-distributed-tracing#240). `Tracing` no longer pulls in `swift-service-context`, so the Temporal target's `import ServiceContextModule`, which only worked because older `Tracing` versions brought that module in, now fails whenever the latest versions are resolved: ``` TemporalHeaderPropagation.swift:15:8: error: no such module 'ServiceContextModule' ``` This breaks CI on main and on every open PR. ### Modifications - Add `swift-service-context` as a direct dependency of `Temporal` and `TemporalTests`. - Import `ServiceContextModule` in every file that uses `ServiceContext`. `swift-service-context` 1.4.0 keeps `ServiceContext` as a non-deprecated alias for `InstrumentationContext`. Importing it makes that alias win over the deprecated one in `Tracing`. The SDK therefore keeps working with `swift-distributed-tracing` 1.2.0 and later, without requiring 1.6.0. ### Result The SDK builds again against both old and new `swift-distributed-tracing` versions, and adopters aren't forced to upgrade. ### Test Plan Built with `-warnings-as-errors` and ran the tracing interceptor and OTel tests against `swift-distributed-tracing` 1.6.0 with `swift-service-context` 1.4.0, and against 1.4.1 with 1.3.0.

kukushechkin added the 🆕 semver/minor Adds new public API. label Sep 9, 2026

kukushechkin added 4 commits September 23, 2026 13:34

[implementation] move ServiceContext to SDT

ecc5eb1

[proposal] move ServiceContext to SDT

67fba63

fixup! [implementation] move ServiceContext to SDT

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fixup! [proposal] move ServiceContext to SDT

2f61cd5

kukushechkin force-pushed the move-service-context-to-sdt branch from 72d78ea to 2f61cd5 Compare September 23, 2026 12:35

kukushechkin added 2 commits September 23, 2026 14:26

fixup! [implementation] move ServiceContext to SDT

8b27668

fixup! [implementation] move ServiceContext to SDT

349b064

kukushechkin mentioned this pull request Sep 23, 2026

[SDT-0002]: (SSC side) move ServiceContext from SSC to SDT implementation apple/swift-service-context#92

Merged

kukushechkin requested review from FranzBusch, czechboy0, heckj, ktoso and slashmo September 24, 2026 12:33

kukushechkin marked this pull request as ready for review September 24, 2026 12:33

FranzBusch approved these changes Sep 24, 2026

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czechboy0 reviewed Sep 24, 2026

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heckj reviewed Sep 24, 2026

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kukushechkin and others added 2 commits September 25, 2026 12:47

add the new module to the spi docs

cb10235

Apply batched suggestions from code review

f8d8e5b

Co-authored-by: Joseph Heck <j_heck@apple.com>

kukushechkin requested a review from heckj September 25, 2026 12:05

kukushechkin added 4 commits September 29, 2026 10:25

Rename to InstrumentationContext

c8b3ab0

fixup! Rename to InstrumentationContext

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fixup! Rename to InstrumentationContext

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Merge branch 'main' into move-service-context-to-sdt

b092fe8

kukushechkin requested a review from czechboy0 October 6, 2026 13:11

czechboy0 reviewed Oct 6, 2026

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Comment thread README.md Outdated

czechboy0 requested changes Oct 6, 2026

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rksharma-owg mentioned this pull request Oct 6, 2026

Add CMake build support #247

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Update README.md

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Co-authored-by: Honza Dvorsky <honza@apple.com>

kukushechkin enabled auto-merge (squash) October 7, 2026 08:55

kukushechkin requested a review from czechboy0 October 7, 2026 14:32

czechboy0 approved these changes Oct 8, 2026

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kukushechkin assigned czechboy0 Oct 9, 2026

czechboy0 disabled auto-merge October 12, 2026 12:13

czechboy0 merged commit 10eb1a1 into apple:main Oct 12, 2026
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williazz mentioned this pull request Oct 12, 2026

fix(deps): update swift-distributed-tracing to 1.6.0 open-telemetry/opentelemetry-swift#1228

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This was referenced Oct 13, 2026

Retry Temporal test / dev server startup apple/swift-temporal-sdk#198

Merged

Declare ServiceContextModule as an explicit dependency apple/swift-temporal-sdk#199

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kukushechkin linked an issue Oct 13, 2026 that may be closed by this pull request

Breaking change - dropped explicit export of ServiceContextModule #251

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