Http-client-csharp server alloy rewrite

[timotheeguerin]

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[Copilot]

Pull request overview

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Copilot was unable to run its full agentic suite in this review.

This PR rewrites the @typespec/http-server-csharp emitter to use Alloy/JSX components and the TypeSpec emitter-framework, alongside updates to build/test configuration and supporting utilities.

Changes:

• Replaces the legacy asset-emitter–based implementation with a new Alloy-based emitter entrypoint and JSX component set.
• Updates TypeScript/Vitest/build configuration to support TSX, Alloy build, and colocated src/**/*.test.* tests.
• Adds new utilities (naming, scalar/type mapping, HTTP helpers, port selection) with unit tests, while removing large legacy implementation files.

Reviewed changes

Copilot reviewed 57 out of 58 changed files in this pull request and generated 4 comments.

Show a summary per file

File	Description
tsconfig.ws.json	Removes the http-server-csharp project reference from the workspace TS build graph.
packages/http-server-csharp/vitest.config.ts	Updates Vitest discovery/setup and adds Alloy Rollup plugin + resolve conditions.
packages/http-server-csharp/tsconfig.json	Switches to NodeNext + TSX settings and declaration-only emit.
packages/http-server-csharp/tsconfig.build.json	Narrows build include/exclude for TS/TSX and omits tests/testing helpers.
packages/http-server-csharp/test/test-host.ts	Adjusts import path for CSharpServiceEmitterOptions.
packages/http-server-csharp/src/utils/type-mapping.ts	Adds intrinsic-scalar→C# mapping and collection type resolution helpers.
packages/http-server-csharp/src/utils/type-mapping.test.ts	Adds unit tests for scalar mapping, collection type, and well-known types.
packages/http-server-csharp/src/utils/port.ts	Adds helper to pick a free TCP port by probing.
packages/http-server-csharp/src/utils/naming.ts	Adds C# identifier casing/escaping and invalid-identifier transformation helpers.
packages/http-server-csharp/src/utils/naming.test.ts	Adds unit tests for naming and identifier validation helpers.
packages/http-server-csharp/src/utils/http-helpers.ts	Adds HTTP verb/status/parameter binding helpers for ASP.NET generation.
packages/http-server-csharp/src/utils/http-helpers.test.ts	Adds unit tests for HTTP helper functions.
packages/http-server-csharp/src/testing/vitest.setup.ts	Adds Alloy testing setup import for Vitest.
packages/http-server-csharp/src/testing/tester.ts	Adds shared TypeSpec Tester instance factory for emitter tests.
packages/http-server-csharp/src/testing/index.ts	Exposes $lib under a ./testing entrypoint.
packages/http-server-csharp/src/lib/type-helpers.ts	Removes legacy type helpers (now replaced by new utilities/components).
packages/http-server-csharp/src/lib/service.ts	Removes the legacy asset-emitter–based server emitter implementation.
packages/http-server-csharp/src/lib/scaffolding.ts	Removes legacy scaffolding generator implementation.
packages/http-server-csharp/src/lib/project.ts	Removes legacy project file generator implementation.
packages/http-server-csharp/src/lib/lib.ts	Updates option docs and removes CSharpServiceOptions singleton.
packages/http-server-csharp/src/lib/interfaces.ts	Removes legacy C# type/attribute/asset-emitter interface layer.
packages/http-server-csharp/src/lib/index.ts	Redirects $onEmit export to the new ./emitter.js.
packages/http-server-csharp/src/lib/doc.ts	Removes legacy docs generator implementation.
packages/http-server-csharp/src/lib/boilerplate.ts	Removes legacy C# boilerplate + converter source file generator.
packages/http-server-csharp/src/lib/attributes.ts	Removes legacy attribute computation implementation.
packages/http-server-csharp/src/emitter.tsx	Adds new Alloy/TypeSpec emitter-framework $onEmit entrypoint.
packages/http-server-csharp/src/components/type-expression.tsx	Adds a C# server-specific TypeSpec type→C# type expression renderer.
packages/http-server-csharp/src/components/type-expression.test.tsx	Adds tests for TypeExpression scalar/array/record/nullable/literal mappings.
packages/http-server-csharp/src/components/serialization/json-converters.tsx	Adds Alloy components emitting static C# JSON helper files.
packages/http-server-csharp/src/components/serialization/json-converters.test.tsx	Adds render tests ensuring helper files are emitted.
packages/http-server-csharp/src/components/scaffolding/mock-scaffolding.tsx	Adds Alloy components emitting mock scaffolding C# files.
packages/http-server-csharp/src/components/scaffolding/mock-scaffolding.test.tsx	Adds render tests for mock scaffolding files.
packages/http-server-csharp/src/components/project/program.tsx	Adds Alloy component emitting ASP.NET Program.cs.
packages/http-server-csharp/src/components/project/program.test.tsx	Adds render tests for Program.cs variations.
packages/http-server-csharp/src/components/project/launch-settings.tsx	Adds Alloy components emitting appsettings + launchSettings.json.
packages/http-server-csharp/src/components/project/launch-settings.test.tsx	Adds render tests for launch settings + appsettings.
packages/http-server-csharp/src/components/project/csproj.tsx	Adds Alloy component emitting a .csproj file.
packages/http-server-csharp/src/components/project/csproj.test.tsx	Adds render tests for .csproj (with/without Swagger package).
packages/http-server-csharp/src/components/output.tsx	Adds small wrapper around emitter-framework Output.
packages/http-server-csharp/src/components/models.tsx	Adds model enumeration + per-model file emission scaffolding.
packages/http-server-csharp/src/components/models.test.tsx	Adds tests using emitter-framework ClassDeclaration for models.
packages/http-server-csharp/src/components/interfaces.tsx	Adds business-logic interface generation component.
packages/http-server-csharp/src/components/interfaces.test.tsx	Adds tests for business-logic interface generation.
packages/http-server-csharp/src/components/enums.tsx	Adds enum enumeration + per-enum file emission scaffolding.
packages/http-server-csharp/src/components/enums.test.tsx	Adds tests using emitter-framework EnumDeclaration.
packages/http-server-csharp/src/components/controllers.tsx	Adds ASP.NET controller class generation component.
packages/http-server-csharp/src/components/controllers.test.tsx	Adds tests for controller class generation.
packages/http-server-csharp/src/components/controller-action.tsx	Adds per-operation controller action generation component.
packages/http-server-csharp/src/components/controller-action.test.tsx	Adds tests for controller actions (GET, DELETE with path param).
packages/http-server-csharp/src/cli/cli.ts	Updates CLI to use new port utility path.
packages/http-server-csharp/package.json	Switches build to alloy build, updates exports/main, adds Alloy deps.
AGENTS.md	Adds repo guidance pointing to installed Alloy docs.
.github/agents/alloy-style.agent.md	Adds an Alloy style-review agent configuration.
.github/agents/alloy-language-package-reviewer.agent.md	Adds an Alloy language package reviewer agent configuration.
.github/agents/alloy-debugger.agent.md	Adds an Alloy debugging agent configuration and guidance.
.github/agents/alloy-architect.agent.md	Adds an Alloy architecture agent configuration and guidance.

Files not reviewed (1)

• pnpm-lock.yaml: Language not supported

Comments suppressed due to low confidence (8)

packages/http-server-csharp/src/emitter.tsx:1

• The new $onEmit currently writes only empty directories and does not invoke any of the new components (Models/Enums/Controllers/serialization/scaffolding/project files). This is a functional regression versus the previous emitter, because compiling with @typespec/http-server-csharp would produce no artifacts. Wire the new component tree into this output (e.g., render Models, Enums, controller/interface generation, and any required helper files) so the emitter actually generates source files.
  packages/http-server-csharp/test/test-host.ts:1
• This import path looks inconsistent with the new folder layout shown in this diff (src/lib/index.ts, src/lib/lib.ts, src/emitter.tsx). Unless a new src/lib.ts barrel exists elsewhere, ../src/lib.js won't resolve and will break test utilities at runtime. Update the import to the correct module that exports CSharpServiceEmitterOptions (or add a barrel file that actually compiles to dist/src/lib.js).
  packages/http-server-csharp/src/testing/index.ts:1
• This re-export targets ../lib.js, but the diff shows the library code living under src/lib/ (e.g., src/lib/index.ts, src/lib/lib.ts). If src/lib.ts / src/lib.js doesn't exist, the ./testing export will be broken. Point this to the actual compiled library entry (e.g., the src/lib/index.ts output) or introduce a barrel module that matches this export.
  packages/http-server-csharp/vitest.config.ts:1
• Using only the development condition for Vitest module resolution is likely incorrect for Alloy-based packages and can lead to duplicate framework instances or the wrong entrypoints being loaded during tests. Consider aligning Vitest's resolve conditions with the package's intended export conditions (commonly including a source condition for tests/dev) and ensure SSR resolve conditions are also configured if needed.
  packages/http-server-csharp/src/utils/port.ts:1
• Port selection has two concrete issues: (1) Math.random() * diff never selects max (range is effectively [min, max)), and (2) when tries is exhausted it returns min without verifying it's free, which can yield an in-use port and cause flaky failures. Make the range inclusive (or document exclusivity) and, on exhaustion, throw or deterministically scan the range and only return a verified free port.
  packages/http-server-csharp/src/utils/http-helpers.ts:1
• The comment claims this converts TypeSpec path params, but the implementation is currently a pure passthrough. Either implement the documented conversion (or validation/normalization) or update the comment to match the current behavior to avoid misleading future changes.
  tsconfig.ws.json:1
• Removing packages/http-server-csharp/tsconfig.build.json from the workspace references can cause this package to be skipped by root TS build workflows (e.g., tsc -b tsconfig.ws.json) and may lead to CI/build drift if other packages still depend on it. If the intent is to fully migrate away from TS project references, consider updating the root build pipeline accordingly; otherwise, re-add the reference.
  packages/http-server-csharp/src/utils/type-mapping.test.ts:1
• A new intrinsic scalar variant (unixTimestamp32) is added to scalarMap in type-mapping.ts, but the test suite here doesn’t assert its mapping. Add a focused test case for scalarMap.get(\"unixTimestamp32\") to prevent regressions in this server-specific scalar behavior.

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commit: deff9fa

[github-actions]

All changed packages have been documented.

• ✅ @typespec/emitter-framework
• ✅ @typespec/http-canonicalization
• ✅ @typespec/http-server-csharp

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@typespec/http-server-csharp - feature ✏️

Rewrite using alloy and emitter framework

@typespec/emitter-framework - internal ✏️

@typespec/http-canonicalization - internal ✏️

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