Add diagnostic analyzer for service registration validation by pwelter34 · Pull Request #298 · loresoft/Injectio

pwelter34 · 2026-04-03T00:28:15Z

Summary

Introduces a new diagnostic analyzer (ServiceRegistrationAnalyzer) that validates Injectio service registration attributes and methods at compile-time, providing developers with immediate feedback on configuration errors.

Key Changes

New ServiceRegistrationAnalyzer class: A Roslyn-based diagnostic analyzer that validates:
- [RegisterServices] method signatures (must have IServiceCollection as first parameter, optional string collection as second)
- Service registration attributes ([RegisterSingleton], [RegisterScoped], [RegisterTransient])
- Factory method existence, static modifier, and signature validation
- Service type assignability (implementation must implement/inherit from declared service types)
- Abstract type instantiation without factory methods
- Non-static [RegisterServices] methods on abstract classes
New DiagnosticDescriptors class: Defines 9 diagnostic rules (INJECT0001-INJECT0009) with appropriate severity levels and user-friendly messages
Comprehensive test suite (ServiceRegistrationDiagnosticTests): 14 test cases covering:
- Invalid method signatures and parameters
- Factory method validation scenarios
- Service type mismatch detection
- Valid registration patterns (no false positives)

Implementation Details

Analyzer registers symbol actions for both SymbolKind.Method and SymbolKind.NamedType
Validates generic type arguments and named parameters from registration attributes
Supports multiple registration strategies (Self, ImplementedInterfaces, SelfWithInterfaces, SelfWithProxyFactory)
Uses fully qualified type names with nullable reference type modifiers for accurate type comparison
Validates factory method signatures support both keyed and non-keyed service registration patterns

https://claude.ai/code/session_01FpKv78qmKTTnNZAGyXxGwv

Introduce compile-time diagnostics (INJECT0001-INJECT0009) that warn about invalid RegisterServices method signatures, missing/invalid factory methods, service-implementation type mismatches, and abstract type issues. Diagnostics are captured as equatable DiagnosticInfo records during the semantic transform phase to maximize incremental generator pipeline caching. https://claude.ai/code/session_01FpKv78qmKTTnNZAGyXxGwv

Reporting diagnostics inside the source generator prevents pipeline caching from working optimally. Move all validation into a dedicated ServiceRegistrationAnalyzer (DiagnosticAnalyzer) that runs independently, keeping the generator focused on pure code generation. - Add ServiceRegistrationAnalyzer with RegisterSymbolAction for methods and named types - Revert ServiceRegistrationGenerator to original (no diagnostic logic) - Remove DiagnosticInfo.cs (no longer needed without generator-side serialization) - Revert ServiceRegistrationContext (remove Diagnostics property) - Update tests to use CompilationWithAnalyzers https://claude.ai/code/session_01FpKv78qmKTTnNZAGyXxGwv

Move duplicated helper methods (IsMethodAttribute, IsKnownAttribute, IsServiceCollection, IsStringCollection, IsServiceProvider, ResolveRegistrationStrategy, FullyQualifiedNullableFormat) into a shared SymbolHelpers class used by both the generator and analyzer. https://claude.ai/code/session_01FpKv78qmKTTnNZAGyXxGwv

Update package reference from xunit 2.9.3 to xunit.v3 1.1.0 to match the v3 runner already in use. Replace Xunit.Abstractions usings with Xunit (ITestOutputHelper moved in v3). https://claude.ai/code/session_01FpKv78qmKTTnNZAGyXxGwv

…generic validation - Replace Verify.Xunit (pulls xunit v2 transitively) with Verify.XunitV3 - Remove xunit.runner.visualstudio (bundled in xunit v3) - Add AnalyzerReleases.Shipped.md and AnalyzerReleases.Unshipped.md for RS2008 release tracking compliance - Move ToUnboundGenericType to shared SymbolHelpers - Fix false positive INJECT0007 for open generic registrations by comparing unbound generic forms of interfaces and base types https://claude.ai/code/session_01FpKv78qmKTTnNZAGyXxGwv

…on warnings - Remove ITestOutputHelper parameter from test base classes (XUnit.Hosting v4 TestHostBase constructor takes only the fixture) - Use SymbolEqualityComparer.Default.Equals instead of != for ISymbol comparisons to fix RS1024 warnings https://claude.ai/code/session_01FpKv78qmKTTnNZAGyXxGwv

Copilot

Pull request overview

Adds a Roslyn diagnostic analyzer to validate Injectio service registration patterns at compile time, and updates the test projects to use xUnit v3 while refactoring shared symbol/type helpers used by the generator/analyzer.

Changes:

Added ServiceRegistrationAnalyzer + DiagnosticDescriptors (INJECT0001–INJECT0009) and Roslyn analyzer release tracking files.
Refactored generator symbol/type utilities into new SymbolHelpers and updated ServiceRegistrationGenerator to use it.
Added analyzer-focused unit tests and migrated test projects/packages to xUnit v3 + Verify.XunitV3.

Reviewed changes

Copilot reviewed 14 out of 14 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
tests/Injectio.Tests/ServiceRegistrationDiagnosticTests.cs	New tests validating analyzer diagnostics for common invalid/valid registration patterns
tests/Injectio.Tests/Injectio.Tests.csproj	Switch test dependencies to xUnit v3 and Verify.XunitV3
tests/Injectio.Acceptance.Tests/LocalServiceTests.cs	Update constructor/base usage to align with updated test host pattern
tests/Injectio.Acceptance.Tests/LibraryServiceTests.cs	Update constructor/base usage to align with updated test host pattern
tests/Injectio.Acceptance.Tests/Injectio.Acceptance.Tests.csproj	Switch acceptance tests to xUnit v3
tests/Injectio.Acceptance.Tests/DependencyInjectionBase.cs	Remove ITestOutputHelper plumbing and update TestHostBase inheritance
src/Injectio.Generators/SymbolHelpers.cs	New shared symbol/type helper utilities extracted for generator/analyzer use
src/Injectio.Generators/ServiceRegistrationGenerator.cs	Replace in-file helpers with `SymbolHelpers` usages
src/Injectio.Generators/ServiceRegistrationAnalyzer.cs	New analyzer implementing service/module registration validation diagnostics
src/Injectio.Generators/Injectio.Generators.csproj	Include analyzer release tracking files as AdditionalFiles
src/Injectio.Generators/DiagnosticDescriptors.cs	New centralized diagnostic descriptors for analyzer rules
src/Injectio.Generators/AnalyzerReleases.Unshipped.md	New (unshipped) analyzer rule tracking entries
src/Injectio.Generators/AnalyzerReleases.Shipped.md	New shipped analyzer rule tracking stub
Directory.Packages.props	Update package versions for Verify + xUnit v3 and remove xUnit v2 packages

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Copilot · 2026-04-03T02:59:56Z

src/Injectio.Generators/SymbolHelpers.cs

+    public static bool IsStringCollection(IParameterSymbol parameterSymbol)
+    {
+        var type = parameterSymbol?.Type as INamedTypeSymbol;
+
+        return type is
+        {
+            Name: "IEnumerable" or "IReadOnlySet" or "IReadOnlyCollection" or "ICollection" or "ISet" or "HashSet",
+            IsGenericType: true,
+            TypeArguments.Length: 1,
+            TypeParameters.Length: 1,
+            ContainingNamespace:
+            {
+                Name: "Generic",
+                ContainingNamespace:
+                {
+                    Name: "Collections",
+                    ContainingNamespace.Name: "System"
+                }
+            }
+        };
+    }


IsStringCollection only checks that the parameter type is a generic collection type, but it never verifies that the generic argument is string. This will incorrectly treat IEnumerable<int> (etc.) as a valid tags parameter for [RegisterServices], and both the generator and analyzer will then accept/assume string tags.

Copilot · 2026-04-03T02:59:56Z

src/Injectio.Generators/ServiceRegistrationAnalyzer.cs

+        if (context.Symbol is not INamedTypeSymbol classSymbol)
+            return;
+
+        if (classSymbol.IsAbstract || classSymbol.IsStatic)


AnalyzeNamedType returns early for classSymbol.IsAbstract, which makes the INJECT0008 (abstract implementation type) check in AnalyzeRegistrationAttribute unreachable for attributes applied to abstract types. If the intent is to warn on abstract registrations, remove/adjust this early return and ensure the diagnostic is emitted for abstract types without a factory.

Suggested change

if (classSymbol.IsAbstract || classSymbol.IsStatic)

if (classSymbol.IsStatic)

Copilot · 2026-04-03T02:59:56Z

src/Injectio.Generators/ServiceRegistrationAnalyzer.cs

+                    location,
+                    factoryMethodName,
+                    className));
+            }


ValidateFactoryMethod enforces parameter count and that the first parameter is IServiceProvider, but it does not validate the type of the optional second parameter (the descriptor message says it must be object?). As written, Factory(IServiceProvider, int) would be accepted; please validate the second parameter type when Parameters.Length == 2.

Suggested change

}

}

if (method.Parameters.Length == 2 &&

method.Parameters[1].Type.SpecialType != SpecialType.System_Object)

{

context.ReportDiagnostic(Diagnostic.Create(

DiagnosticDescriptors.FactoryMethodInvalidSignature,

location,

factoryMethodName,

className));

}

Copilot · 2026-04-03T02:59:56Z

src/Injectio.Generators/ServiceRegistrationAnalyzer.cs

+        foreach (var method in factoryMethods)
+        {
+            if (!method.IsStatic)
+            {
+                context.ReportDiagnostic(Diagnostic.Create(
+                    DiagnosticDescriptors.FactoryMethodNotStatic,
+                    location,
+                    factoryMethodName,
+                    className));
+                return;
+            }
+
+            if (method.Parameters.Length is not (1 or 2))
+            {
+                context.ReportDiagnostic(Diagnostic.Create(
+                    DiagnosticDescriptors.FactoryMethodInvalidSignature,
+                    location,
+                    factoryMethodName,
+                    className));
+                return;
+            }
+
+            if (!SymbolHelpers.IsServiceProvider(method.Parameters[0]))
+            {
+                context.ReportDiagnostic(Diagnostic.Create(
+                    DiagnosticDescriptors.FactoryMethodInvalidSignature,
+                    location,
+                    factoryMethodName,
+                    className));
+            }
+        }


Factory method validation reports diagnostics based on the first overload encountered and can false-positive when multiple overloads share the same name (e.g., one non-static overload plus one valid static overload). Consider changing the logic to: (1) find at least one overload that is static and has a valid signature, and only (2) report a diagnostic if no valid overload exists.

Suggested change

foreach (var method in factoryMethods)

{

if (!method.IsStatic)

{

context.ReportDiagnostic(Diagnostic.Create(

DiagnosticDescriptors.FactoryMethodNotStatic,

location,

factoryMethodName,

className));

return;

}

if (method.Parameters.Length is not (1 or 2))

{

context.ReportDiagnostic(Diagnostic.Create(

DiagnosticDescriptors.FactoryMethodInvalidSignature,

location,

factoryMethodName,

className));

return;

}

if (!SymbolHelpers.IsServiceProvider(method.Parameters[0]))

{

context.ReportDiagnostic(Diagnostic.Create(

DiagnosticDescriptors.FactoryMethodInvalidSignature,

location,

factoryMethodName,

className));

}

}

var hasStaticOverload = false;

foreach (var method in factoryMethods)

{

if (!method.IsStatic)

continue;

hasStaticOverload = true;

if (method.Parameters.Length is not (1 or 2))

continue;

if (!SymbolHelpers.IsServiceProvider(method.Parameters[0]))

continue;

return;

}

context.ReportDiagnostic(Diagnostic.Create(

hasStaticOverload

? DiagnosticDescriptors.FactoryMethodInvalidSignature

: DiagnosticDescriptors.FactoryMethodNotStatic,

location,

factoryMethodName,

className));

Copilot · 2026-04-03T02:59:57Z

src/Injectio.Generators/ServiceRegistrationAnalyzer.cs

+        // validate abstract implementation type without factory
+        if (classSymbol.IsAbstract && implementationFactory.IsNullOrWhiteSpace() && implTypeName == classSymbol.ToDisplayString(SymbolHelpers.FullyQualifiedNullableFormat))
+        {
+            context.ReportDiagnostic(Diagnostic.Create(
+                DiagnosticDescriptors.AbstractImplementationType,
+                location,
+                implTypeName));
+        }


There’s no test exercising INJECT0008 (abstract implementation type without a factory). Since this analyzer rule is newly introduced, it should have a dedicated test case to prevent regressions once the abstract-type analysis logic is fixed/updated.

- Remove IsAbstract early return in AnalyzeNamedType so INJECT0008 is reachable for abstract types with registration attributes - Rewrite factory validation to find any valid overload before reporting, avoiding false positives with multiple overloads - Validate factory second parameter is object? (not arbitrary types) - Add string type argument check to IsStringCollection (reject IEnumerable<int> etc.) - Add tests for INJECT0008 (abstract type with/without factory) - Fix TestHostBase constructor for XUnit.Hosting v4 (single fixture parameter, no ITestOutputHelper) https://claude.ai/code/session_01FpKv78qmKTTnNZAGyXxGwv

claude added 6 commits April 2, 2026 20:30

Migrate from xunit v2 to xunit.v3

79f382e

Update package reference from xunit 2.9.3 to xunit.v3 1.1.0 to match the v3 runner already in use. Replace Xunit.Abstractions usings with Xunit (ITestOutputHelper moved in v3). https://claude.ai/code/session_01FpKv78qmKTTnNZAGyXxGwv

pwelter34 requested a review from Copilot April 3, 2026 02:54

Copilot started reviewing on behalf of pwelter34 April 3, 2026 02:55 View session

Copilot AI reviewed Apr 3, 2026

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Add diagnostic analyzer for service registration validation#298

Add diagnostic analyzer for service registration validation#298
pwelter34 wants to merge 7 commits intomainfrom
claude/add-source-generator-diagnostics-wB78i

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	if (classSymbol.IsAbstract \|\| classSymbol.IsStatic)
	if (classSymbol.IsStatic)

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pwelter34 commented Apr 3, 2026

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