feat!: omit constructor parameters overloads for interfaces and types with only parameterless constructors

[vbreuss]

This PR updates the Mockolate source generator to stop emitting public CreateMock(... constructorParameters ...) overloads for interfaces and for classes that only have a parameterless constructor, reducing the generated API surface for types that don’t need constructor forwarding.

Changes:

• Add generator tests asserting that constructor-parameters overloads are omitted for parameterless-only and implicit-ctor classes.
• Update mock class source generation to only emit constructor-parameter overloads when a type has at least one accessible parameterized constructor.
• Make the internal “core” CreateMock(MockBehavior?, setup?, object?[]?) helper private for types without parameterized constructors.

[Copilot]

Pull request overview

This PR updates the Mockolate source generator to stop emitting public CreateMock(... constructorParameters ...) overloads for interfaces and for classes that only have a parameterless constructor, reducing the generated API surface for types that don’t need constructor forwarding.

Changes:

• Add generator tests asserting that constructor-parameters overloads are omitted for parameterless-only and implicit-ctor classes.
• Update mock class source generation to only emit constructor-parameter overloads when a type has at least one accessible parameterized constructor.
• Make the internal “core” CreateMock(MockBehavior?, setup?, object?[]?) helper private for types without parameterized constructors.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 1 comment.

File	Description
Tests/Mockolate.SourceGenerators.Tests/MockTests.cs	Adds coverage for omitting constructor-parameter overloads on parameterless-only classes.
Source/Mockolate.SourceGenerators/Sources/Sources.MockClass.cs	Gates constructor-parameter overload generation based on presence of accessible parameterized constructors; adjusts helper visibility accordingly.

Comments suppressed due to low confidence (1)

Source/Mockolate.SourceGenerators/Sources/Sources.MockClass.cs:130

• By omitting the public CreateMock(..., object?[] ...) overloads for parameterless-only classes, calls like MyType.CreateMock(new object?[]{ }) can now bind to the generic fallback overload emitted in Mock.g.cs (extension<T>(T _)), which compiles but always throws at runtime. To avoid this regression, consider also preventing the fallback overload from being applicable (e.g., remove the fallback constructor-parameters overloads altogether) or emit a type-specific overload that fails at compile time (such as [Obsolete(..., error: true)]) for types where constructor parameters are not supported.

		}
		createMockRemarks.Add("</list>");
		createMockRemarks.Add("With the default behavior, un-configured members return <c>default</c> values (empty collections / strings, completed tasks, <see langword=\"null\" /> otherwise) and base-class implementations are invoked for class mocks. Use one of the overloads that accepts a <see cref=\"global::Mockolate.MockBehavior\" /> to customize this (for example to make un-configured calls throw or to skip the base class).");
		createMockRemarks.Add("Overloads allow you to additionally pass constructor parameters (for class mocks), apply an initial <c>setup</c> callback before the instance is returned, or combine both.");

		sb.AppendXmlSummary(
			$"Creates a new mock of <see cref=\"{escapedClassName}\" /> with the default <see cref=\"global::Mockolate.MockBehavior\" />.");
		sb.AppendXmlRemarks(createMockRemarks.ToArray());

[github-actions]

🚀 Benchmark Results

Details

BenchmarkDotNet v0.15.8, Linux Ubuntu 24.04.4 LTS (Noble Numbat)

AMD EPYC 7763 2.45GHz, 1 CPU, 4 logical and 2 physical cores

.NET SDK 10.0.203

[Host] : .NET 10.0.7 (10.0.7, 10.0.726.21808), X64 RyuJIT x86-64-v3
Job=InProcess  Toolchain=InProcessEmitToolchain  IterationCount=15

LaunchCount=1  WarmupCount=10

Method	Mean	Error	StdDev	Ratio	RatioSD	Gen0	Gen1	Allocated	Alloc Ratio
Event_Mockolate	422.1 ns	8.25 ns	7.72 ns	1.00	0.02	0.0849	-	1.39 KB	1.00
Event_Moq	16,183.9 ns	288.34 ns	255.60 ns	38.35	0.89	0.7324	-	12.51 KB	9.00
Event_NSubstitute	5,487.3 ns	65.07 ns	60.87 ns	13.00	0.27	0.5493	0.0076	9.05 KB	6.51
Event_FakeItEasy	211,459.9 ns	1,563.23 ns	1,462.24 ns	501.10	9.42	0.7324	0.4883	15.39 KB	11.06
Event_Imposter	1,432.6 ns	51.00 ns	47.71 ns	3.39	0.12	0.5379	0.0153	8.8 KB	6.33
Event_TUnitMocks	183.6 ns	4.21 ns	3.73 ns	0.44	0.01	0.0837	0.0002	1.37 KB	0.98

Details

BenchmarkDotNet v0.15.8, Linux Ubuntu 24.04.4 LTS (Noble Numbat)

Intel Xeon Platinum 8370C CPU 2.80GHz (Max: 2.88GHz), 1 CPU, 4 logical and 2 physical cores

.NET SDK 10.0.203

[Host] : .NET 10.0.7 (10.0.7, 10.0.726.21808), X64 RyuJIT x86-64-v4
Job=InProcess  Toolchain=InProcessEmitToolchain  IterationCount=15

LaunchCount=1  WarmupCount=10

Method	N	Mean	Error	StdDev	Ratio	RatioSD	Gen0	Gen1	Allocated	Alloc Ratio
Indexer_Mockolate	1	828.8 ns	9.60 ns	8.98 ns	1.00	0.01	0.0944	-	2.32 KB	1.00
Indexer_Moq	1	138,199.8 ns	693.70 ns	579.27 ns	166.77	1.88	0.4883	0.2441	14.57 KB	6.28
Indexer_NSubstitute	1	6,210.8 ns	14.75 ns	13.80 ns	7.49	0.08	0.3815	-	9.39 KB	4.05
Indexer_FakeItEasy	1	6,295.6 ns	59.11 ns	52.40 ns	7.60	0.10	0.3281	0.0153	8.1 KB	3.49
Indexer_Imposter	1	944.3 ns	31.70 ns	29.65 ns	1.14	0.04	0.1965	0.0019	4.84 KB	2.09
Indexer_Mockolate	10	3,067.1 ns	10.82 ns	10.12 ns	1.00	0.00	0.1526	-	3.83 KB	1.00
Indexer_Moq	10	144,370.7 ns	806.18 ns	714.66 ns	47.07	0.27	0.7324	0.4883	18.47 KB	4.83
Indexer_NSubstitute	10	8,793.4 ns	51.09 ns	47.79 ns	2.87	0.02	0.4730	-	11.85 KB	3.10
Indexer_FakeItEasy	10	9,776.8 ns	123.62 ns	115.63 ns	3.19	0.04	0.6409	-	15.81 KB	4.13
Indexer_Imposter	10	1,656.4 ns	30.47 ns	28.51 ns	0.54	0.01	0.2594	0.0038	6.39 KB	1.67

Details

BenchmarkDotNet v0.15.8, Linux Ubuntu 24.04.4 LTS (Noble Numbat)

AMD EPYC 7763 2.45GHz, 1 CPU, 4 logical and 2 physical cores

.NET SDK 10.0.203

[Host] : .NET 10.0.7 (10.0.7, 10.0.726.21808), X64 RyuJIT x86-64-v3
Job=InProcess  Toolchain=InProcessEmitToolchain  IterationCount=15

LaunchCount=1  WarmupCount=10

Method	N	Mean	Error	StdDev	Ratio	RatioSD	Gen0	Gen1	Allocated	Alloc Ratio
Method_Mockolate	1	628.3 ns	6.98 ns	6.53 ns	1.00	0.01	0.1364	-	2.23 KB	1.00
Method_Moq	1	183,104.7 ns	754.08 ns	668.48 ns	291.48	3.10	0.4883	-	14.73 KB	6.59
Method_NSubstitute	1	5,820.5 ns	43.43 ns	38.50 ns	9.27	0.11	0.5569	0.0076	9.12 KB	4.08
Method_FakeItEasy	1	6,239.9 ns	24.35 ns	22.78 ns	9.93	0.11	0.4959	-	8.11 KB	3.63
Method_Imposter	1	591.1 ns	4.73 ns	4.42 ns	0.94	0.01	0.2470	0.0029	4.04 KB	1.81
Method_TUnitMocks	1	689.6 ns	13.26 ns	12.40 ns	1.10	0.02	0.1774	0.0010	2.9 KB	1.30
Method_Mockolate	10	2,258.1 ns	24.83 ns	23.23 ns	1.00	0.01	0.3357	-	5.5 KB	1.00
Method_Moq	10	187,682.8 ns	1,230.79 ns	1,151.29 ns	83.12	0.96	0.9766	0.7324	18.64 KB	3.39
Method_NSubstitute	10	8,711.0 ns	48.90 ns	45.74 ns	3.86	0.04	0.7324	0.0153	12.07 KB	2.19
Method_FakeItEasy	10	9,576.0 ns	57.83 ns	54.09 ns	4.24	0.05	0.9766	0.0305	16.05 KB	2.92
Method_Imposter	10	1,237.8 ns	13.93 ns	13.03 ns	0.55	0.01	0.3376	0.0057	5.52 KB	1.00
Method_TUnitMocks	10	1,707.5 ns	12.04 ns	10.68 ns	0.76	0.01	0.2747	0.0019	4.49 KB	0.82

Details

BenchmarkDotNet v0.15.8, Linux Ubuntu 24.04.4 LTS (Noble Numbat)

Intel Xeon Platinum 8370C CPU 2.80GHz (Max: 2.71GHz), 1 CPU, 4 logical and 2 physical cores

.NET SDK 10.0.203

[Host] : .NET 10.0.7 (10.0.7, 10.0.726.21808), X64 RyuJIT x86-64-v4
Job=InProcess  Toolchain=InProcessEmitToolchain  IterationCount=15

LaunchCount=1  WarmupCount=10

Method	N	Mean	Error	StdDev	Ratio	RatioSD	Gen0	Gen1	Allocated	Alloc Ratio
Property_Mockolate	1	539.5 ns	28.91 ns	27.04 ns	1.00	0.07	0.0610	-	1.52 KB	1.00
Property_Moq	1	3,907.0 ns	41.72 ns	32.57 ns	7.26	0.35	0.2136	-	5.48 KB	3.61
Property_NSubstitute	1	4,863.3 ns	116.42 ns	108.90 ns	9.03	0.47	0.3510	-	8.63 KB	5.70
Property_FakeItEasy	1	4,197.1 ns	148.72 ns	139.11 ns	7.80	0.44	0.2594	-	6.4 KB	4.23
Property_Imposter	1	528.3 ns	41.40 ns	38.73 ns	0.98	0.08	0.1183	0.0010	2.91 KB	1.92
Property_TUnitMocks	1	643.5 ns	32.48 ns	30.38 ns	1.20	0.08	0.0820	-	2.03 KB	1.34
Property_Mockolate	10	2,050.9 ns	56.65 ns	52.99 ns	1.00	0.04	0.1526	-	3.8 KB	1.00
Property_Moq	10	5,452.9 ns	143.45 ns	134.19 ns	2.66	0.09	0.3204	-	7.96 KB	2.10
Property_NSubstitute	10	7,176.7 ns	164.00 ns	145.39 ns	3.50	0.11	0.4578	0.0076	11.3 KB	2.98
Property_FakeItEasy	10	7,353.0 ns	224.15 ns	198.70 ns	3.59	0.13	0.5341	-	13.41 KB	3.53
Property_Imposter	10	909.7 ns	47.55 ns	44.47 ns	0.44	0.02	0.1440	0.0010	3.55 KB	0.93
Property_TUnitMocks	10	1,753.0 ns	28.93 ns	27.06 ns	0.86	0.02	0.1202	-	2.97 KB	0.78

Details

BenchmarkDotNet v0.15.8, Linux Ubuntu 24.04.4 LTS (Noble Numbat)

Intel Xeon Platinum 8370C CPU 2.80GHz, 1 CPU, 4 logical and 2 physical cores

.NET SDK 10.0.203

[Host] : .NET 10.0.7 (10.0.7, 10.0.726.21808), X64 RyuJIT x86-64-v4
Job=InProcess  Toolchain=InProcessEmitToolchain  IterationCount=15

LaunchCount=1  WarmupCount=10

Method	Mean	Error	StdDev	Ratio	RatioSD	Gen0	Gen1	Allocated	Alloc Ratio
Callback_Mockolate	498.8 ns	3.98 ns	3.32 ns	1.00	0.01	0.0658	-	1.62 KB	1.00
Callback_Moq	71,165.7 ns	290.56 ns	242.63 ns	142.67	1.02	0.2441	-	8.88 KB	5.49
Callback_NSubstitute	4,482.2 ns	12.72 ns	11.28 ns	8.99	0.06	0.3128	0.0076	7.74 KB	4.79
Callback_FakeItEasy	4,673.0 ns	21.33 ns	19.95 ns	9.37	0.07	0.2747	-	6.8 KB	4.20
Callback_Imposter	530.5 ns	9.69 ns	9.06 ns	1.06	0.02	0.0963	-	2.38 KB	1.47
Callback_TUnitMocks	791.6 ns	4.89 ns	4.34 ns	1.59	0.01	0.1068	0.0010	2.63 KB	1.62

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
91.7% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[github-actions]

Test Results

    21 files      21 suites   7m 39s ⏱️
 3 285 tests  3 284 ✅ 1 💤 0 ❌
21 504 runs  21 503 ✅ 1 💤 0 ❌

Results for commit fa6f0fc.

[github-actions]

This is addressed in release v3.0.0.