[Core] Explicitly Support gzip & deflate for Encodings in Aiohttp by kashifkhan · Pull Request #48388 · Azure/azure-sdk-for-python

kashifkhan · 2026-07-31T14:56:36Z

This PR addresses an issue with aiohttp and core. Today aiohttp automatically appends br (Brotli) and zstd to the Accept-Encoding request header when it detects the corresponding optional library (e.g. brotli / brotlicffi ) installed in the environment.

When the service honors that and returns a Brotli-encoded response, azure-core can't decode it: the aiohttp transport runs with auto_decompress=False and decompresses manually, supporting only gzip / deflate , so the raw bytes reach response.text() and raise a UnicodeDecodeError

Request does similar, but lets requests/urllib3 decompress the response itself, so it decodes whatever it advertised

We do the following:

Explicitly pass in gzip and deflate for aiohttp
Move the aiohttp body helper into the aiohttp section; its not generic and used only by aiohttp
Update tests

azure-pipelines · 2026-07-31T14:57:23Z

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Pull request overview

Restricts AioHttpTransport to supported response encodings, preventing decoding failures when optional aiohttp codecs are installed.

Changes:

Defaults Accept-Encoding to gzip, deflate while preserving caller overrides.
Relocates the aiohttp-specific body helper.
Adds tests and updates package metadata.

Reviewed changes

Copilot reviewed 6 out of 6 changed files in this pull request and generated 1 comment.

Show a summary per file

File	Description
`azure/core/pipeline/transport/_aiohttp.py`	Sets supported encodings and hosts the body helper.
`azure/core/rest/_aiohttp.py`	Imports the relocated helper.
`azure/core/utils/_pipeline_transport_rest_shared.py`	Removes aiohttp-specific logic.
`tests/async_tests/test_universal_http_async.py`	Tests defaults and caller overrides.
`CHANGELOG.md`	Documents the fix.
`azure/core/_version.py`	Bumps the version to 1.42.0.

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Pull request overview

Copilot reviewed 6 out of 6 changed files in this pull request and generated no new comments.

JennyPng

looks good to me

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Pull request overview

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Copilot

Pull request overview

Copilot reviewed 5 out of 5 changed files in this pull request and generated no new comments.

Suppressed comments (1)

sdk/core/azure-core/azure/core/pipeline/transport/_aiohttp.py:345

A preconfigured ClientSession can supply its own default Accept-Encoding (for example, identity or an encoding supported by its custom decompressor). aiohttp gives these per-request headers precedence over session defaults, so this unconditional request default silently replaces that user configuration. Check the session headers before adding the transport fallback, and add coverage for an injected session with a custom default header.

        request.headers.setdefault("Accept-Encoding", _SUPPORTED_ACCEPT_ENCODING)

Copilot

Pull request overview

Copilot reviewed 5 out of 5 changed files in this pull request and generated no new comments.

Suppressed comments (1)

sdk/core/azure-core/azure/core/pipeline/transport/_aiohttp.py:191

This only constrains sessions created by the transport. An injected aiohttp.ClientSession(auto_decompress=False) with no explicit Accept-Encoding still falls back to ClientRequest.DEFAULT_HEADERS, so environments with Brotli/Zstandard installed can continue advertising br/zstd; send() then selects azure-core's gzip/deflate-only manual decompression and the original decode failure remains. When auto_decompress is false, set the supported header at request time only if neither the request nor the injected session supplies one, and add coverage for that injected-session case.

                    "headers": {"Accept-Encoding": _SUPPORTED_ACCEPT_ENCODING},

github-actions · 2026-08-03T19:01:51Z

[Pilot] PR Pipeline Failure Analysis

A CI pipeline failed on this pull request. Here is an automated analysis of what went wrong and how to get the build green.

What failed

Three distinct failure groups were detected:

[Build/Infrastructure] pnpm dependency resolution — Pipeline 6651431 failed during a build task with ERR_PNPM_BAD_CONFIG_DEP: Cannot resolve pnpm@9.5.0 as a package manager dependency because it has no integrity. This is a tooling/infrastructure issue unrelated to PR code changes.
[Test] azure-ai-textanalytics — 14 tests in tests.test_* (e.g., test_abstract_summary, test_recognize_entities, test_text_sentiment, etc.) failed consistently across macOS (Python 3.11), Ubuntu (Python 3.10), and Windows (Python 3.12) — all three platforms and all install modes (whl, sdist, mindependency). The breadth of failures across platforms and test categories suggests a service-side or environment issue rather than a regression from this PR.
[Test] azure-cosmos retry policies — TestServiceRetryPolicies.test_service_request_retry_policy (Python 3.10) and test_service_response_retry_policy (Python 3.11) failed on Windows Emulator tests. These are unrelated to the aiohttp Accept-Encoding changes in this PR.

Recommended next steps

For the pnpm failure: Re-run the pipeline — this is an infrastructure/dependency resolution issue (pnpm@9.5.0 integrity missing). No code changes should be required. If it recurs, it may need to be escalated to the engineering system team.
For the textanalytics and cosmos failures: Check whether these failures are pre-existing or appear on main as well. They span many unrelated test areas and all platforms, pointing to environment/service issues rather than a regression introduced by this PR.
See the CI troubleshooting guide: https://aka.ms/ci-fix
Push new commits to address any failures confirmed to be caused by this PR; this comment updates automatically on the next failing run.

Raw pipeline analysis (azsdk ci analyze)

Analyzing pipeline https://github.com/Azure/azure-sdk-for-python/pull/48388...
--------------------------------------------------------------------------------
Failed Tests
--------------------------------------------------------------------------------
Cosmos (Windows/Python3.10): tests.test_service_retry_policies.TestServiceRetryPolicies.test_service_request_retry_policy
Cosmos (Windows/Python3.11): tests.test_service_retry_policies.TestServiceRetryPolicies.test_service_response_retry_policy

azure-ai-textanalytics (macOS/Ubuntu/Windows, mindependency+whl+sdist):
  test_abstract_summary, test_extract_key_phrases, test_extract_summary,
  test_health_care_lro, test_language_detection, test_multi_label_classify,
  test_recognize_entities, test_recognize_entities_ner,
  test_recognize_linked_entities, test_recognize_pii,
  test_recognize_pii_confidence_score, test_recognize_pii_redaction_policies,
  test_single_label_classify, test_text_sentiment

--------------------------------------------------------------------------------
Failed Tasks
--------------------------------------------------------------------------------
### Errors:
ERR_PNPM_BAD_CONFIG_DEP
  × resolve package manager dependencies
  ╰─▶ Cannot resolve pnpm@9.5.0 as a package manager dependency because it has no integrity

### Pipeline: https://dev.azure.com/azure-sdk/public/_build/results?buildId=6651431

Copilot detected the failing pipeline and generated the analysis above. To have it attempt a fix automatically, reply with @copilot please fix the failing pipeline on this PR.

Generated by Pipeline Analysis - Next Steps · 28.6 AIC · ⌖ 6.32 AIC · ⊞ 6.6K · ◷

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Copilot AI review requested due to automatic review settings July 31, 2026 20:25

kashifkhan force-pushed the azcore_comp_hdr branch from a9f7bcf to 2d688d8 Compare July 31, 2026 20:25

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Copilot AI review requested due to automatic review settings August 3, 2026 14:34

kashifkhan added 8 commits August 3, 2026 09:35

update changelog

6813456

explicitly support gzip and deflate; move body helper method here

b660d50

update import

e3366c3

remove aiohttp specific helper from here

d0bd54f

update tests

05067cf

update changelog

79b182e

remove space in changelog

b39b2b6

fix mypy error by casting

c0dfaf1

Copilot started reviewing on behalf of kashifkhan August 3, 2026 14:35 View session

kashifkhan force-pushed the azcore_comp_hdr branch from 6b923f3 to c0dfaf1 Compare August 3, 2026 14:35

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ensure user provided overrides are honored

2bdb1e5

Copilot AI review requested due to automatic review settings August 3, 2026 15:45

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[Core] Explicitly Support gzip & deflate for Encodings in Aiohttp - #48388

[Core] Explicitly Support gzip & deflate for Encodings in Aiohttp#48388
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