fix(ktor): resolve client hang on streaming path with Ktor 3.5.0

[amccague]

#18779

Two changes to fix requests hanging when using prepareGet().execute {}:

1. Request pipeline: replace withContext(asContextElement()) { proceed() } with attribute-based context passing. Ktor 3.5.0 (KTOR-9546) added a responseJobHolder as a child of the call job in DefaultTransform, which delays call job completion. withContext wrapping proceed() at request pipeline scope prevents the call from returning promptly. The parent context is now passed via request attributes to the send pipeline where createSpan consumes it.

2. Receive pipeline: replace scope.launch { job.join(); endSpan() } with job.invokeOnCompletion { endSpan() }. The launched coroutine waited on the call job which no longer completes promptly due to KTOR-9546's responseJobHolder child. invokeOnCompletion fires synchronously when the job reaches terminal state without suspending or leaking coroutines.

[linux-foundation-easycla]

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• ✅ login: amccague / name: Adrian McCague (990ffb4)

[Copilot]

Pull request overview

This PR addresses Ktor 3.5.0 client hangs on streaming prepareGet().execute {} calls by avoiding coroutine context wrapping at request-pipeline scope and ending spans via job completion callbacks.

Changes:

• Pass the parent OpenTelemetry context through Ktor request attributes into span creation.
• Replace the receive-pipeline launch { job.join() } span-end flow with invokeOnCompletion.
• Add a streaming regression test and update Ktor 3 test/runtime dependencies to 3.5.0.

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
instrumentation/ktor/ktor-common-2.0/library/src/main/kotlin/io/opentelemetry/instrumentation/ktor/common/v2_0/internal/KtorClientTelemetryUtil.kt	Updates context propagation and span-ending logic for Ktor client instrumentation.
instrumentation/ktor/ktor-common-2.0/library/src/main/kotlin/io/opentelemetry/instrumentation/ktor/common/v2_0/AbstractKtorClientTelemetry.kt	Adds a createSpan overload accepting an explicit parent context.
instrumentation/ktor/ktor-3.0/testing/build.gradle.kts	Raises shared Ktor 3 testing dependencies to 3.5.0.
instrumentation/ktor/ktor-3.0/library/src/test/kotlin/io/opentelemetry/instrumentation/ktor/v3_0/KtorHttpClientStreamingTest.kt	Adds a regression test for streaming client requests with telemetry installed.
instrumentation/ktor/ktor-3.0/library/build.gradle.kts	Raises Ktor 3 library/test dependency version to 3.5.0.
instrumentation/ktor/ktor-3.0/javaagent/build.gradle.kts	Raises Ktor 3 javaagent library/test dependency version to 3.5.0.

Comments suppressed due to low confidence (1)

instrumentation/ktor/ktor-3.0/library/src/test/kotlin/io/opentelemetry/instrumentation/ktor/v3_0/KtorHttpClientStreamingTest.kt:75

• [Testing] This regression test only verifies that the streaming request returns; it does not assert that the client span is actually ended/exported after the invokeOnCompletion path runs. Since this PR changes span-ending behavior for this exact path, the test would still pass if the request completed but telemetry was silently dropped.

          client.prepareGet("http://localhost:$serverPort/success").execute { response ->
            response.bodyAsText()
          }

[Copilot]

Pull request overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated 2 comments.

[Copilot]

Pull request overview

Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.

[laurit]

did you consider adding this test to AbstractKtorHttpClientTest?

[amccague]

I've done this, I prefer it a bit more self-contained because of the pre-requisites but have a look at what I've done with comments to explain themselves.

[otelbot]

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