opentelemetry-instrumentation-pika: prevent duplicate consumer spans

[aivinay]

Description

Updates opentelemetry-instrumentation-pika so consumer callbacks that were already decorated by the instrumentation are not wrapped again when channel consumers are re-instrumented.

This keeps newly registered consumers decorated while preventing stacked callback wrappers from producing duplicate consumer spans.

Fixes #4667

Type of change

• Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

• uvx --with tox-uv tox -e py314-test-instrumentation-sio-pika-1-wrapt2 -- instrumentation/opentelemetry-instrumentation-pika/tests/test_pika_instrumentation.py
• uvx --with tox-uv tox -e py314-test-instrumentation-sio-pika-0-wrapt1 -- instrumentation/opentelemetry-instrumentation-pika/tests/test_pika_instrumentation.py
• uvx --with tox-uv tox -e lint-instrumentation-sio-pika
• uvx ruff check instrumentation/opentelemetry-instrumentation-pika/src/opentelemetry/instrumentation/pika/pika_instrumentor.py instrumentation/opentelemetry-instrumentation-pika/tests/test_pika_instrumentation.py
• uvx ruff format --check instrumentation/opentelemetry-instrumentation-pika/src/opentelemetry/instrumentation/pika/pika_instrumentor.py instrumentation/opentelemetry-instrumentation-pika/tests/test_pika_instrumentation.py

Does This PR Require a Core Repo Change?

• No.

Checklist:

• Followed the style guidelines of this project
• Changelogs have been updated
• Unit tests have been added
• Documentation update is not required

[linux-foundation-easycla]

The committers listed above are authorized under a signed CLA.

• ✅ login: aivinay / name: Vinay Gupta (5fe700f)

[herin049]

Can we include a test case which is similar to the reproduction example in the original issue?

[Copilot]

Pull request overview

This PR updates the opentelemetry-instrumentation-pika consumer callback instrumentation to avoid re-wrapping callbacks that were already decorated, preventing stacked wrappers from emitting duplicate nested CONSUMER spans when basic_consume is invoked multiple times on the same channel.

Changes:

• Skip decorating consumer callbacks in _instrument_channel_consumers when they already carry the _original_callback marker.
• Adjust and add unit tests to verify already-decorated callbacks are not wrapped again.
• Add a changelog fragment documenting the fix.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated no comments.

File	Description
instrumentation/opentelemetry-instrumentation-pika/src/opentelemetry/instrumentation/pika/pika_instrumentor.py	Adds a guard to prevent double-wrapping already-instrumented consumer callbacks.
instrumentation/opentelemetry-instrumentation-pika/tests/test_pika_instrumentation.py	Updates existing assertions and adds a targeted regression test for the duplicate-span scenario.
.changelog/4740.fixed	Records the bug fix in the changelog fragments.

[aivinay]

Can we include a test case which is similar to the reproduction example in the original issue?

Thanks, @herin049! Added a regression test based on the issue reproduction: three consumers on one channel, one q1 delivery, and an assertion that only one q1 receive CONSUMER span is emitted.