[Akash Sarangi (Roxen-AS)]

Fixes #12356

Description

When a bytes body is used with a binary content type (such as application/octet-stream), the compiler sets the default byte encoding to "none". However, @typespec/http-client-js's scalar-transform.tsx only explicitly handled "base64" and "base64url", falling through to emit an unknown-encoding warning for "none".

This PR:

1. Handles case "none": return passthroughTransformer(itemRef); in both toTransport and toApplication byte transforms in scalar-transform.tsx.
2. Adds unit test coverage verifying that an operation with a bytes body and binary content type emits cleanly without any unknown-encoding diagnostics.
3. Adds a Chronus changelog entry.

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[Copilot]

🟡 Changes recommended

The unsupported-encoding test does not trigger its expected diagnostic, and response-side warning regression coverage is missing.

2 open issues

• Property-level encoding bypasses the byte transformer · New
• Tests do not assert diagnostics for the toApplication branch · New

What changed in this PR

Fixes #12356 by treating "none" as a supported byte encoding in the JavaScript HTTP client emitter, avoiding warnings for raw binary bodies.

Changes:

• Adds passthrough handling for byte serialization and deserialization.
• Adds tests for binary-body diagnostics and unsupported encodings.
• Adds a Chronus fix entry.

File	Description
packages/​http-client-js/​test/​bytes-none-encoding.test.ts	Adds encoding diagnostic tests.
packages/​http-client-js/​src/​components/​transforms/​scalar-transform.tsx	Handles "none" encoding in both transform directions.
.chronus/​changes/​fix-http-client-js-bytes-none-encoding.md	Documents the warning fix.

_{Review effort: Balanced}

[Copilot]

🟢 Approval recommended

The focused change preserves byte handling and covers both transformation directions, with no unresolved blocking issues from static review; tests were not executed.

1 open issue

• Tests do not assert diagnostics for the toApplication branch

1 resolved since last review

• Property-level encoding bypasses the byte transformer

_{Review effort: Balanced}

[Copilot]

🟢 Approval recommended

The narrow fix preserves byte passthrough behavior, covers both affected directions, and has no identified blocking issues.

No open issues 🎉

1 resolved since last review

• Tests do not assert diagnostics for the toApplication branch

_{Review effort: Balanced}

[pkg-pr-new]

Open in StackBlitz

npm i https://pkg.pr.new/microsoft/typespec/@typespec/http-client-js@12371

commit: d59d4d3

[github-actions]

All changed packages have been documented.

• ✅ @typespec/http-client-js

Show changes

@typespec/http-client-js - fix ✏️

Prevent reporting spurious unknown-encoding warnings for raw bytes body with none encoding (e.g. binary content types such as application/octet-stream).

[Jeff Fisher (xirzec)]

Overall, a good change, but I'd appreciate the commented cleanups before merging.

[Copilot]

🟢 Approval recommended

The focused fix preserves byte passthrough behavior, covers both transformation directions, and retains warnings for unsupported encodings.

No open issues 🎉

_{Review effort: Balanced}

[Copilot]

🟢 Approval recommended

No active review issues are reported for the change supporting raw bytes with "none" encoding.

No open issues 🎉

_{Review effort: Balanced}