Use hybrid C# reference map for post-processing by live1206 · Pull Request #10976 · microsoft/typespec

live1206 · 2026-06-12T04:31:43Z

Summary

Replaces the C# generator's Roslyn-heavy generated-code reference-map construction with a provider/hybrid reference map while preserving generated-output correctness.

Why custom code still uses Roslyn

Generated code has provider metadata for signatures, body dependencies, serialization helpers, and known generated source patterns, so it can avoid building a full Roslyn reference map. Custom/shared code is arbitrary user C#: it can reference generated types through signatures, inheritance, generics, arrays, object creation, static members, extension methods, XML docs, or handwritten helper flows that provider metadata cannot see. This PR therefore keeps Roslyn semantic analysis for custom-code roots/references and uses the faster provider graph for generated-code reachability.

Latest benchmark data

Latest generator PR head: 48862512. Benchmark PR: #10885 (f4a1bbbec). Artifacts: /tmp/typespec-review-fix-bench-20260625-0637.

Scope	Roslyn	Provider/hybrid	Improvement
Full generation median	918.3 ms / 68.02 MB	738.2 ms / 48.48 MB	19.6% faster / 28.7% less allocation
Reference-map profile median	307.7 ms / 23.64 MB	112.3 ms / 7.83 MB	63.5% faster / 66.9% less allocation

Azure SDK local project-reference benchmark

Measured Azure SDK for .NET management-plane regeneration using the same local project-reference setup in both runs: /workspaces/azure-sdk-for-net was wired to the sibling /workspaces/typespec checkout via .NET project references, and only the TypeSpec checkout changed between main and this PR branch.

SDK package	TypeSpec main baseline	This PR branch	Improvement
Azure.ResourceManager.Network	00:37:01.9	00:17:23.9	53.0% faster / 2.13x speedup
Azure.ResourceManager.DataFactory	00:13:43.4	00:07:49.1	43.0% faster / 1.76x speedup

Validation

Latest Azure SDK full regen PR: [DO NOT MERGE] Preview Generator Version 1.0.0-alpha.20260625.1 (Azure data plane) Azure/azure-sdk-for-net#60254.
That regen showed no public API file changes, and all affected SDK services built successfully.
C# generator build and Cop checks passed after the latest changes.

pkg-pr-new · 2026-06-12T04:34:05Z

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npm i https://pkg.pr.new/@typespec/http-client-csharp@10976

commit: 4886251

github-actions · 2026-06-12T04:34:26Z

No changes needing a change description found.

This reverts commit ff55509.

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

ArcturusZhang · 2026-06-25T09:53:08Z

+
+        public static void Analyze(IReadOnlyList<TypeProvider> providers, Project project)
+        {
+            var generatedProviders = GetGeneratedProviders(providers);


I am not sure why we have to exclude the custom code - we might produce incorrect result if custom code is not considered.
Also I think we should do it for CanonicalView of each provider.

explained in PR description, and feel free to continue with this further improvement, I will not cover this part in current PR

Handle duplicate generated providers, avoid namespace-blind API baseline roots, and keep collection result constructors internal so implementation-only REST clients are not publicized. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

live1206 added 2 commits June 12, 2026 04:30

Profile C# post-processing benchmarks

ff55509

Add provider reference map shadow replacement

f022e78

microsoft-github-policy-service Bot added the emitter:client:csharp Issue for the C# client emitter: @typespec/http-client-csharp label Jun 12, 2026

live1206 added 25 commits June 12, 2026 06:31

Revert "Profile C# post-processing benchmarks"

f88a64a

This reverts commit ff55509.

Remove hybrid map diagnostics from generator

2d57265

Rename hybrid reference map components

dc145f4

Document hybrid reference map decisions

0cc3abf

Fix hybrid reference map CI failures

c2abe79

Track serialization providers in hybrid reference map

c463995

Handle model factory subclasses in reference map

9a1d1a1

Track generated body type references

2917111

Match Roslyn cleanup for body references

2cda184

Remove unused serialization providers

ce16922

Merge remote-tracking branch 'origin/main' into mtg-hybrid-reference-map

7a32814

Preserve public discriminator subtypes

5a8248f

Use explicit serialization helper dependencies

43529f3

Use explicit collection result dependencies

21ecc1a

Use explicit client body dependencies

f3259a4

Track rest client helper dependencies

b6e8aad

Skip stubbed client body dependencies

48885cb

Internalize models from final API reachability

c6539de

Update model root visibility test

f676243

Detect custom model factory providers

0a37522

Preserve file header when removing usings

582fa84

Limit derived public reachability to discriminators

74be26d

Ignore custom roots for derived public reachability

dc6f0f2

Propagate public discriminator reachability transitively

7c20ef2

Keep enum serialization helpers reachable

2e4af08

live1206 and others added 17 commits June 22, 2026 01:47

Merge remote-tracking branch 'origin/main' into mtg-hybrid-reference-map

11ac8ba

fix(http-client-csharp): preserve rest client helper references

ce1fef1

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

fix(http-client-csharp): limit helper reference fallback

281af2a

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

fix(http-client-csharp): preserve generated internal accessibility

12338c4

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

fix(http-client-csharp): preserve last contract roots

9bbb09c

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

perf(http-client-csharp): use current generated roots

47998b8

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

fix(http-client-csharp): preserve hybrid reference map parity

4117135

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

fix(http-client-csharp): keep non-azure union roots

fa09582

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

fix(http-client-csharp): keep enum serialization dependencies

d055a32

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

fix(http-client-csharp): retain custom enum serialization providers

0eb6ca5

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

fix(http-client-csharp): scan serialization provider references

b8a5c3a

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

fix(http-client-csharp): preserve base-kept dependencies

912ffe0

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

perf(http-client-csharp): reduce provider reference map analysis cost

88bea57

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

fix(http-client-csharp): preserve generated client helpers

18b8131

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Merge origin/main into mtg-hybrid-reference-map

4e4f67e

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

fix(http-client-csharp): add braces for cop check

d58bebe

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

fix(http-client-csharp): preserve provider map signature reachability

6fe237f

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

live1206 marked this pull request as ready for review June 25, 2026 08:58

live1206 requested review from JoshLove-msft, ShivangiReja, jorgerangel-msft, joseharriaga, jsquire and m-nash as code owners June 25, 2026 08:58

live1206 changed the title ~~[Draft] Use hybrid C# reference map for post-processing~~ Use hybrid C# reference map for post-processing Jun 25, 2026

fix(http-client-csharp): preserve custom array signature roots

70bc6ea

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

ArcturusZhang reviewed Jun 25, 2026

View reviewed changes

live1206 mentioned this pull request Jun 25, 2026

Track MPG body-only helper dependencies Azure/azure-sdk-for-net#60257

Draft

fix(http-client-csharp): keep paging collection constructors public

4886251

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

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Use hybrid C# reference map for post-processing#10976

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live1206 commented Jun 12, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Summary

Why custom code still uses Roslyn

Latest benchmark data

Azure SDK local project-reference benchmark

Validation

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live1206 commented Jun 12, 2026 •

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