[python] add support for exact client name

[iscai-msft]

cc @dargilco @howieleung

Once this is in, you can add @clientName(exact("stream"), "python") to your stream parameter and it won't get padded. It will also help with other instances where you don't want case conversion or padding. We will generate exactly what's passed into the exact function, we won't do any snake casing either.

[github-actions]

All changed packages have been documented.

• ✅ @typespec/http-client-python

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@typespec/http-client-python - feature ✏️

add support for exact client names

[pkg-pr-new]

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npm i https://pkg.pr.new/@typespec/http-client-python@10750

commit: 577830b

[azure-sdk-automation]

You can try these changes here

🛝 Playground	🌐 Website	🛝 VSCode Extension

[dargilco]

That's awesome! thank you @iscai-msft !!!

[tadelesh]

Can we move the judgement to a helper function and do not repeat in every place?

[Copilot]

Pull request overview

Adds support in the Python emitter/generator pipeline for “exact” client names so a @clientName(exact("..."), "python") override can bypass snake_case conversion and reserved-word padding (notably enabling stream without auto-suffixing).

Changes:

• Emit and propagate an isExactName flag for parameters/properties and use it to choose between exact vs snake_case client naming.
• Update Python preprocessing/codegen to skip lowercasing/padding when isExactName is set, and avoid consuming the internal stream kwarg when a parameter is exactly named stream.
• Add a Chronus changelog entry for @typespec/http-client-python.

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
packages/http-client-python/generator/pygen/preprocess/init.py	Skips lowercasing/padding for exact names; updates property-to-parameter mapping handling.
packages/http-client-python/generator/pygen/codegen/serializers/builder_serializer.py	Attempts to adjust kwargs popping behavior for exact-name params.
packages/http-client-python/generator/pygen/codegen/models/parameter.py	Adds is_exact_name on parameters from YAML.
packages/http-client-python/generator/pygen/codegen/models/operation.py	Adds exact_name_params helper and uses it to avoid stream kwarg consumption.
packages/http-client-python/emitter/src/utils.ts	Introduces getClientName() helper and includes isExactName in param base emission.
packages/http-client-python/emitter/src/types.ts	Emits model property isExactName and uses getClientName() for property client names.
packages/http-client-python/emitter/src/http.ts	Propagates isExactName for flattened/body parameters and uses getClientName() for body param naming.
.chronus/changes/python-addExactSupport-2026-4-20-15-34-6.md	Adds changelog entry for the feature.