Add SystemObjectModelProvider for non-generated base type customization by live1206 · Pull Request #9862 · microsoft/typespec

live1206 · 2026-03-02T09:37:32Z

Summary

Adds SystemObjectModelProvider, a ModelProvider subclass for input models that map to existing framework/system model types such as TrackedResourceData and ResourceData. This lets downstream generators, especially the Azure Management generator, use non-generated framework types as model bases while still allowing the base generator to reason about inherited properties, constructors, and serialization.

Key changes

`SystemObjectModelProvider`

Represents a framework/system model type using a CSharpType plus the InputModelType it replaces.
Extends ModelProvider, unlike SystemObjectTypeProvider, so it can be used as BaseModelProvider for generated derived models.
Exposes SystemType and CrossLanguageDefinitionId for downstream generator logic.
Uses the framework type name/namespace and never writes a generated file.
Builds properties and constructors from the input model so derived models can correctly pass inherited constructor parameters such as id, name, resourceType, systemData, tags, and location.
Does not generate fields, serialization providers, or a raw data field because the framework type owns those implementation details.

Model inheritance handling

ModelProvider.BuildBaseModelProvider() now resolves customized base types through BaseType, including generated-model customizations and a name+namespace fallback for framework/non-framework CSharpType equality differences.
ModelProvider.Update(...) now accepts baseModelProvider, replacing the earlier dedicated setter API and resetting cached members when the base changes.
Property generation deduplicates against a SystemObjectModelProvider base chain, so derived generated models do not re-emit framework-owned properties.
Raw-data and serialization behavior now accounts for SystemObjectModelProvider bases.

Constructor initializer fix

Fixed base constructor initializer argument selection after public input parameters are substituted. This prevents generated code like : base(location0) when the actual constructor parameter is location.

Motivation

The Azure Management generator has ARM resource models that inherit from framework types such as TrackedResourceData and ResourceData. Previously it needed a local InheritableSystemObjectModelProvider with custom constructor and property handling. Moving this capability into the shared generator lets downstream generators reuse normal ModelProvider behavior for inheritance, property deduplication, serialization modifiers, and constructor generation.

Validation

npm run build:generator in packages/http-client-csharp passes.
Validated with the companion Azure SDK PR using the local TypeSpec checkout:
- eng/packages/http-client-csharp-mgmt/eng/scripts/Generate.ps1 completed successfully.
- dotnet test eng/packages/http-client-csharp-mgmt/generator/Azure.Generator.Management/test/Azure.Generator.Mgmt.Tests.csproj passed: 194/194 tests.

Companion PR

SDK: Fix: Respect custom base type override for inheritable system types in mgmt generator Azure/azure-sdk-for-net#56634

…ed fallback Add SystemObjectModelProvider extending ModelProvider for downstream generators that map input models to existing framework types (e.g., ARM Resource to ResourceData). Unlike SystemObjectTypeProvider which extends TypeProvider, this class can serve as BaseModelProvider for derived models. Fix BuildBaseModelProvider() to use name+namespace based CSharpTypeMap fallback when strict CSharpType equality fails. This resolves the case where custom code overrides a base type to an external type (e.g., TrackedResourceData) but the CSharpTypeMap lookup fails due to framework vs non-framework CSharpType mismatch. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

…ObjectModelProvider - Added CrossLanguageDefinitionId property (from input model) to support downstream generators that need to check the cross-language definition ID - Fixed BuildName() null safety: _systemType may be null when called from base constructor before field assignment (same pattern as BuildNamespace) Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

pkg-pr-new · 2026-03-02T09:39:36Z

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npm i https://pkg.pr.new/@typespec/http-client-csharp@9862

commit: 8239c8d

github-actions · 2026-03-02T09:40:06Z

No changes needing a change description found.

…ovider from upstream Use SystemObjectModelProvider from Microsoft.TypeSpec.Generator instead of the local InheritableSystemObjectModelProvider. This aligns with the upstream PR microsoft/typespec#9862 which adds SystemObjectModelProvider to the base generator. - ManagementTypeFactory: create SystemObjectModelProvider(replacedType, model) - InheritableSystemObjectModelVisitor: swap all type checks and property access - NameVisitor: use SystemObjectModelProvider pattern match - ManagementOutputLibrary: filter SystemObjectModelProvider Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

…zation, and constructors - SystemObjectModelProvider now returns empty for BuildProperties, BuildFields, BuildSerializationProviders, BuildConstructors, and null for BuildRawDataField - ModelProvider.BuildProperties skips base properties when base chain includes SystemObjectModelProvider - ModelProvider.BuildRawDataField changed to protected virtual - MrwSerializationTypeDefinition uses virtual (not override) for create/persist methods when base is SystemObjectModelProvider This enables downstream generators (mgmt) to handle framework type bases natively without post-processing visitors. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Tests demonstrate capabilities that SystemObjectModelProvider provides that are missing from SystemObjectTypeProvider: 1. Type hierarchy: SystemObjectModelProvider extends ModelProvider (not TypeProvider), so it can serve as BaseModelProvider for derived models 2. Property deduplication: derived models skip properties defined in framework base 3. Raw data field: SystemObjectModelProvider returns null, derived models create own 4. Empty members: no generated properties/fields/constructors/serialization 5. Serialization modifiers: correct virtual vs override for 4 serialization methods 6. Name/namespace from system CSharpType Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

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

…se property dedup from SystemObjectModelProvider chain - SetBaseModelProvider: public method allowing visitors to replace a model's base - Reset override: clears rawDataField, additionalPropertyFields/Properties, fullConstructor - InputModel property: exposes the private _inputModel field for external use - BuildProperties: when base is SystemObjectModelProvider, also includes base properties from its InputModel chain for proper dedup when custom code overrides base type Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Remove BuildProperties() => [] and BuildConstructors() => [] overrides so that SystemObjectModelProvider builds properties and constructors from its input model. This allows derived models to correctly include base class parameters (e.g., id, name, resourceType, systemData, tags, location) in their constructors and generate proper :base() initializer calls. Without this fix, derived models lose all base class constructor parameters because the empty overrides make the base model invisible to the constructor building logic in ModelProvider.BuildConstructorParameters(). Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Access _inputModel directly in BuildProperties() since private members are accessible within the declaring class on any instance. This avoids adding unnecessary public API surface. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Fold base model provider changes into ModelProvider.Update() instead of a separate public SetBaseModelProvider() method. This follows the existing Update() pattern and automatically resets dependent members when the base model changes. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

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

…er' into feature/system-object-model-provider

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

jorgerangel-msft · 2026-05-12T17:30:04Z

                        {
                            outputProperty.Modifiers |= MethodSignatureModifiers.New;
-                            var fieldName = $"_{baseProperty.Name.ToVariableName()}";
+                            var fieldName = $"_{baseProperty.Property.Name.ToVariableName()}";


why are there so many changes here? Can we also get a regen preview please?

live1206 and others added 2 commits March 2, 2026 16:56

microsoft-github-policy-service Bot added the emitter:client:csharp Issue for the C# client emitter: @typespec/http-client-csharp label Mar 2, 2026

live1206 and others added 5 commits March 2, 2026 18:20

Fix spellcheck: replace 'dedup' with 'deduplication'

87b2621

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

live1206 mentioned this pull request Mar 5, 2026

Fix: Respect custom base type override for inheritable system types in mgmt generator Azure/azure-sdk-for-net#56634

Draft

live1206 and others added 2 commits March 5, 2026 16:10

microsoft-github-policy-service Bot added the stale Mark a PR that hasn't been recently updated and will be closed. label Apr 4, 2026

Merge branch 'main' into feature/system-object-model-provider

9985aa3

live1206 removed the stale Mark a PR that hasn't been recently updated and will be closed. label May 9, 2026

live1206 and others added 3 commits May 11, 2026 15:35

Merge remote-tracking branch 'origin/main' into feature/system-object…

7580c13

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

Merge remote-tracking branch 'live/feature/system-object-model-provid…

0603d4f

…er' into feature/system-object-model-provider

Fix base constructor initializer parameters

9449ee2

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

live1206 marked this pull request as ready for review May 11, 2026 09:21

live1206 requested review from JoshLove-msft, ShivangiReja, christothes, jorgerangel-msft, joseharriaga, jsquire and m-nash as code owners May 11, 2026 09:21

Consolidate constructor conversion helper

4ee286a

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

jorgerangel-msft reviewed May 11, 2026

View reviewed changes

Comment thread ...ges/http-client-csharp/generator/Microsoft.TypeSpec.Generator/src/Providers/ModelProvider.cs Outdated

Comment thread ...ges/http-client-csharp/generator/Microsoft.TypeSpec.Generator/src/Providers/ModelProvider.cs Outdated

Fix nullable enum constructor initializer conversion

fbcb1e0

JoshLove-msft reviewed May 12, 2026

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Comment thread ...ges/http-client-csharp/generator/Microsoft.TypeSpec.Generator/src/Providers/ModelProvider.cs Outdated

JoshLove-msft reviewed May 12, 2026

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Comment thread ...ges/http-client-csharp/generator/Microsoft.TypeSpec.Generator/src/Providers/ModelProvider.cs Outdated

Refine system object base provider handling

5d7dc77

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

JoshLove-msft reviewed May 12, 2026

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Comment thread ...tor/Microsoft.TypeSpec.Generator.ClientModel/src/Providers/MrwSerializationTypeDefinition.cs Outdated

live1206 and others added 2 commits May 12, 2026 12:09

Avoid concrete system model provider serialization check

1ce6f36

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

Keep JSON write core override for system bases

8239c8d

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

jorgerangel-msft reviewed May 12, 2026

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Add SystemObjectModelProvider for non-generated base type customization#9862

Add SystemObjectModelProvider for non-generated base type customization#9862
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Summary

Key changes

SystemObjectModelProvider

Model inheritance handling

Constructor initializer fix

Motivation

Validation

Companion PR

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live1206 commented Mar 2, 2026 •

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`SystemObjectModelProvider`

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