fix: support mocking types from extern-aliased references by vbreuss · Pull Request #921 · Testably/Mockolate

vbreuss · 2026-10-31T08:11:15Z

Types from a reference that is only reachable through an extern alias (for example <Aliases>Legacy</Aliases> on a PackageReference/ProjectReference, typically used to consume two versions of the same assembly) do not resolve under global::. The generated mock therefore failed to compile with CS0400, so such types could not be mocked at all.

Changes

Types from an assembly that is reachable only through an extern alias are now qualified with that alias (Legacy::Ns.IFoo) instead of global::. This covers mocked types, member signatures, containing types of explicit implementations, generic constraints, enum default values and attribute arguments.
Each generated file that uses an alias declares it (extern alias Legacy;) directly after the auto-generated header. Every generator output receives the alias list, so no file can use an alias without declaring it.
Assemblies that are also reachable through global (a second reference without an alias, or Aliases="global,Legacy") keep the global:: qualification.
Attribute array arguments are now serialized element by element with the same rules as single arguments. Before, enum elements were emitted as plain numbers (new Color[]{1}, CS0266) and Type elements as bare names (new Type[]{string}, CS1525), independent of extern aliases. A null array argument now becomes null.

Tests

An extern-aliased reference: interfaces, abstract classes, delegates, Implementing<T>() combinations, indexers, events, enum defaults and attributes (including enum and typeof values inside arrays) are qualified with the alias. Every file using the alias also declares it.
A reference that is also reachable through global, as a separate reference and via global,Alias, keeps global::.
An unresolved type in a mocked member while an extern alias is present no longer makes the generator throw (CS8785) and drop all other mocks.
Attribute array arguments with enum, Type, mixed object[] and null values compile.

Types from a reference that is only reachable through an extern alias do not resolve under `global::`, so the generated mock failed to compile (CS0400). The generator now qualifies such types with their alias and declares it in the generated file.

github-actions · 2026-10-31T08:17:37Z

Test Results

31 files ± 0 31 suites ±0 48m 15s ⏱️ + 10m 23s
4 536 tests + 5 4 536 ✅ + 5 0 💤 ±0 0 ❌ ±0
28 837 runs +15 28 837 ✅ +15 0 💤 ±0 0 ❌ ±0

Results for commit 22ade35. ± Comparison against base commit 797cfc2.

This pull request removes 22 and adds 21 tests. Note that renamed tests count towards both.

 x-myHeader3: baz, True)
)
Mockolate.Internal.Tests.Internals.WildcardTests ‑ ShouldSupportMultilineStrings(
Mockolate.Internal.Tests.Internals.WildcardTests ‑ ShouldSupportMultilineStrings(
Mockolate.SourceGenerators.Tests.MethodSetupsTests ‑ WhenImplementingObjectMethods_ShouldUseSpecialInterfaces(bool Equals(object obj);
Mockolate.SourceGenerators.Tests.MethodSetupsTests ‑ WhenImplementingObjectMethods_ShouldUseSpecialInterfaces(bool Equals(object obj);
Mockolate.SourceGenerators.Tests.MethodSetupsTests ‑ WhenImplementingObjectMethods_ShouldUseSpecialInterfaces(string ToString();
Mockolate.SourceGenerators.Tests.MethodSetupsTests ‑ WhenImplementingObjectMethods_ShouldUseSpecialInterfaces(string ToString();
Mockolate.Tests.Web.ItExtensionsTests+IsHttpContentTests+WithHeadersTests ‑ ShouldVerifyStringHeaders(x-myHeader1 : foo
Mockolate.Tests.Web.ItExtensionsTests+IsHttpContentTests+WithHeadersTests ‑ ShouldVerifyStringHeaders(x-myHeader1 : foo
…

Mockolate.Internal.Tests.Internals.WildcardTests ‑ ShouldSupportMultilineStrings(
)
Mockolate.Internal.Tests.Internals.WildcardTests ‑ ShouldSupportMultilineStrings(
)
Mockolate.SourceGenerators.Tests.GeneralTests ‑ WithArrayAttributeArguments_ShouldSerializeEachElementByItsKind
Mockolate.SourceGenerators.Tests.MethodSetupsTests ‑ WhenImplementingObjectMethods_ShouldUseSpecialInterfaces(bool Equals(object obj);
int GetHashCode();, public override bool Equals(object obj), public override int GetHashCode())
Mockolate.SourceGenerators.Tests.MethodSetupsTests ‑ WhenImplementingObjectMethods_ShouldUseSpecialInterfaces(bool Equals(object obj);
int GetHashCode();, public override bool Equals(object obj), public override int GetHashCode())
Mockolate.SourceGenerators.Tests.MethodSetupsTests ‑ WhenImplementingObjectMethods_ShouldUseSpecialInterfaces(string ToString();
bool Equals(object obj);, public override string ToString(), public override bool Equals(object obj))
Mockolate.SourceGenerators.Tests.MethodSetupsTests ‑ WhenImplementingObjectMethods_ShouldUseSpecialInterfaces(string ToString();
bool Equals(object? obj);
int GetHashCode();, public override string ToString(), public override int GetHashCode(), public override bool Equals(object? obj))
Mockolate.SourceGenerators.Tests.MethodSetupsTests ‑ WhenImplementingObjectMethods_ShouldUseSpecialInterfaces(string ToString();
int GetHashCode();, public override string ToString(), public override int GetHashCode())
Mockolate.SourceGenerators.Tests.MethodSetupsTests ‑ WhenImplementingObjectMethods_ShouldUseSpecialInterfaces(string ToString();
bool Equals(object obj);, public override string ToString(), public override bool Equals(object obj))
Mockolate.SourceGenerators.Tests.MethodSetupsTests ‑ WhenImplementingObjectMethods_ShouldUseSpecialInterfaces(string ToString();
bool Equals(object? obj);
int GetHashCode();, public override string ToString(), public override int GetHashCode(), public override bool Equals(object? obj))
…

♻️ This comment has been updated with latest results.

github-actions · 2026-10-31T08:21:32Z

🚀 Benchmark Results

Details

BenchmarkDotNet v0.15.8, Linux Ubuntu 26.04.1 LTS (Resolute Raccoon)

AMD EPYC 9V45 4.37GHz, 1 CPU, 4 logical and 2 physical cores

.NET SDK 10.0.303

[Host] : .NET 10.0.14 (10.0.14, 10.0.1426.52326), X64 RyuJIT x86-64-v4
Job=InProcess  Toolchain=InProcessEmitToolchain  IterationCount=15

LaunchCount=1  WarmupCount=10

Method	N	Mean	Error	StdDev	Ratio	Allocated	Alloc Ratio
baseline*	1	199.8 ns	4.53 ns	4.02 ns	0.97	1976 B	1.00
Mockolate	1	207.0 ns	5.14 ns	4.55 ns	1.00	1976 B	1.00
Imposter	1	141.8 ns	3.81 ns	3.57 ns	0.69	928 B	0.47
TUnitMocks	1	301.2 ns	11.40 ns	10.10 ns	1.46	2088 B	1.06
Moq	1	58,198.3 ns	1,328.62 ns	1,177.79 ns	281.23	14944 B	7.56
NSubstitute	1	3,421.0 ns	75.32 ns	70.45 ns	16.53	9336 B	4.72
FakeItEasy	1	3,428.2 ns	95.20 ns	89.05 ns	16.57	8244 B	4.17

baseline*	10	457.5 ns	5.51 ns	4.60 ns	0.91	2192 B	1.00
Mockolate	10	502.0 ns	9.73 ns	8.62 ns	1.00	2192 B	1.00
Imposter	10	365.1 ns	8.35 ns	7.81 ns	0.73	1792 B	0.82
TUnitMocks	10	1,035.3 ns	26.78 ns	23.74 ns	2.06	3840 B	1.75
Moq	10	56,967.6 ns	993.54 ns	929.36 ns	113.52	18930 B	8.64
NSubstitute	10	4,761.8 ns	66.17 ns	61.90 ns	9.49	12360 B	5.64
FakeItEasy	10	5,238.5 ns	62.28 ns	55.21 ns	10.44	15786 B	7.20

Details

BenchmarkDotNet v0.15.8, Linux Ubuntu 26.04.1 LTS (Resolute Raccoon)

AMD EPYC 7763 2.61GHz, 1 CPU, 4 logical and 2 physical cores

.NET SDK 10.0.303

[Host] : .NET 10.0.14 (10.0.14, 10.0.1426.52326), X64 RyuJIT x86-64-v3
Job=InProcess  Toolchain=InProcessEmitToolchain  IterationCount=15

LaunchCount=1  WarmupCount=10

CreateMock	Mean	Error	StdDev	Ratio	Allocated	Alloc Ratio
baseline*	18.49 ns	0.421 ns	0.394 ns	1.03	160 B	1.00
Mockolate	18.03 ns	0.863 ns	0.807 ns	1.00	160 B	1.00
Imposter	115.61 ns	1.393 ns	1.235 ns	6.43	576 B	3.60
TUnitMocks	36.95 ns	1.739 ns	1.627 ns	2.05	216 B	1.35
Moq	1,389.58 ns	5.271 ns	4.402 ns	77.23	2096 B	13.10
NSubstitute	2,038.38 ns	30.450 ns	26.993 ns	113.29	5048 B	31.55
FakeItEasy	1,774.55 ns	19.039 ns	17.809 ns	98.62	2763 B	17.27

Details

BenchmarkDotNet v0.15.8, Linux Ubuntu 26.04.1 LTS (Resolute Raccoon)

AMD EPYC 7763 3.04GHz, 1 CPU, 4 logical and 2 physical cores

.NET SDK 10.0.303

[Host] : .NET 10.0.14 (10.0.14, 10.0.1426.52326), X64 RyuJIT x86-64-v3
Job=InProcess  Toolchain=InProcessEmitToolchain  IterationCount=15

LaunchCount=1  WarmupCount=10

Event	Mean	Error	StdDev	Ratio	Allocated	Alloc Ratio
baseline*	374.3 ns	5.72 ns	5.35 ns	1.30	1744 B	1.00
Mockolate	287.0 ns	11.32 ns	10.59 ns	1.00	1744 B	1.00
Imposter	188.5 ns	4.30 ns	4.02 ns	0.66	512 B	0.29
TUnitMocks	192.1 ns	7.25 ns	6.79 ns	0.67	1392 B	0.80
Moq	15,784.2 ns	42.94 ns	40.16 ns	55.06	12810 B	7.35
NSubstitute	5,946.4 ns	31.69 ns	29.64 ns	20.74	9264 B	5.31
FakeItEasy	220,082.4 ns	868.45 ns	725.19 ns	767.77	15755 B	9.03

Details

BenchmarkDotNet v0.15.8, Linux Ubuntu 26.04.1 LTS (Resolute Raccoon)

AMD EPYC 7763 3.24GHz, 1 CPU, 4 logical and 2 physical cores

.NET SDK 10.0.303

[Host] : .NET 10.0.14 (10.0.14, 10.0.1426.52326), X64 RyuJIT x86-64-v3
Job=InProcess  Toolchain=InProcessEmitToolchain  IterationCount=15

LaunchCount=1  WarmupCount=10

Property	N	Mean	Error	StdDev	Ratio	Allocated	Alloc Ratio
baseline*	1	546.3 ns	18.66 ns	17.45 ns	0.90	2472 B	1.00
Mockolate	1	606.0 ns	11.03 ns	10.32 ns	1.00	2472 B	1.00
Imposter	1	186.0 ns	1.95 ns	1.83 ns	0.31	664 B	0.27
TUnitMocks	1	466.6 ns	5.66 ns	5.02 ns	0.77	1696 B	0.69
Moq	1	12,091.4 ns	90.19 ns	79.95 ns	19.96	10641 B	4.30
NSubstitute	1	8,039.8 ns	87.89 ns	82.21 ns	13.27	11720 B	4.74
FakeItEasy	1	8,977.6 ns	37.20 ns	31.06 ns	14.82	11508 B	4.66

baseline*	10	1,071.9 ns	11.62 ns	9.71 ns	0.94	2976 B	1.00
Mockolate	10	1,141.1 ns	6.93 ns	6.48 ns	1.00	2976 B	1.00
Imposter	10	363.4 ns	2.16 ns	2.02 ns	0.32	952 B	0.32
TUnitMocks	10	1,607.6 ns	19.31 ns	18.07 ns	1.41	4048 B	1.36
Moq	10	19,131.0 ns	83.02 ns	77.65 ns	16.77	18721 B	6.29
NSubstitute	10	18,147.3 ns	87.00 ns	81.38 ns	15.90	21585 B	7.25
FakeItEasy	10	20,723.4 ns	123.50 ns	109.48 ns	18.16	31546 B	10.60

Details

BenchmarkDotNet v0.15.8, Linux Ubuntu 26.04.1 LTS (Resolute Raccoon)

INTEL XEON PLATINUM 8573C 3.05GHz, 1 CPU, 4 logical and 2 physical cores

.NET SDK 10.0.303

[Host] : .NET 10.0.14 (10.0.14, 10.0.1426.52326), X64 RyuJIT x86-64-v4
Job=InProcess  Toolchain=InProcessEmitToolchain  IterationCount=15

LaunchCount=1  WarmupCount=10

Callback	Mean	Error	StdDev	Ratio	Allocated	Alloc Ratio
baseline*	330.2 ns	5.30 ns	4.70 ns	0.82	1608 B	1.00
Mockolate	401.1 ns	4.42 ns	3.92 ns	1.00	1608 B	1.00
Imposter	266.3 ns	1.20 ns	1.12 ns	0.66	744 B	0.46
TUnitMocks	614.5 ns	5.32 ns	4.98 ns	1.53	2064 B	1.28
Moq	43,867.7 ns	215.45 ns	190.99 ns	109.38	9073 B	5.64
NSubstitute	4,191.4 ns	22.37 ns	19.83 ns	10.45	7896 B	4.91
FakeItEasy	3,804.9 ns	13.67 ns	12.78 ns	9.49	6964 B	4.33

Details

BenchmarkDotNet v0.15.8, Linux Ubuntu 26.04.1 LTS (Resolute Raccoon)

INTEL XEON PLATINUM 8573C 3.20GHz, 1 CPU, 4 logical and 2 physical cores

.NET SDK 10.0.303

[Host] : .NET 10.0.14 (10.0.14, 10.0.1426.52326), X64 RyuJIT x86-64-v4
Job=InProcess  Toolchain=InProcessEmitToolchain  IterationCount=15

LaunchCount=1  WarmupCount=10

Indexer	N	Mean	Error	StdDev	Ratio	Allocated	Alloc Ratio
baseline*	1	946.9 ns	33.78 ns	31.60 ns	0.99	3.81 KB	1.00
Mockolate	1	952.6 ns	23.30 ns	21.79 ns	1.00	3.81 KB	1.00
Imposter	1	349.6 ns	7.96 ns	6.65 ns	0.37	1.19 KB	0.31
Moq	1	98,959.9 ns	832.42 ns	737.92 ns	103.94	20.38 KB	5.35
NSubstitute	1	9,447.5 ns	81.81 ns	76.52 ns	9.92	12.78 KB	3.35
FakeItEasy	1	7,601.3 ns	107.84 ns	100.88 ns	7.98	13.62 KB	3.57

baseline*	10	2,508.8 ns	17.38 ns	16.26 ns	0.94	4.87 KB	1.00
Mockolate	10	2,664.2 ns	21.08 ns	19.72 ns	1.00	4.87 KB	1.00
Imposter	10	815.8 ns	16.03 ns	14.21 ns	0.31	2.24 KB	0.46
Moq	10	103,639.3 ns	787.92 ns	698.47 ns	38.90	29.88 KB	6.14
NSubstitute	10	21,718.6 ns	167.87 ns	148.81 ns	8.15	25.58 KB	5.26
FakeItEasy	10	18,292.6 ns	126.69 ns	112.31 ns	6.87	32.98 KB	6.78

baseline* rows show the corresponding Mockolate benchmark from the most recent successful main branch build with results, for regression comparison.

An unresolved namespace-qualified type in a mocked member made the generator throw whenever an extern alias was present, dropping every mock. Attribute array elements ignored their kind, so non-zero enums and types inside arrays did not compile. Every output now receives the aliases explicitly so no file can miss the directive.

sonarqubecloud · 2026-10-31T10:13:45Z

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
97.1% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

…aliased references (#921) by Valentin Breuß

vbreuss self-assigned this Oct 31, 2026

vbreuss merged commit db4bb6c into main Oct 31, 2026
21 checks passed

vbreuss deleted the fix/extern-alias-types branch October 31, 2026 10:33

github-actions Bot added a commit that referenced this pull request Oct 31, 2026

Update benchmark for db4bb6c: fix: support mocking types from extern-…

ace196d

…aliased references (#921) by Valentin Breuß

github-actions Bot added a commit that referenced this pull request Oct 31, 2026

Update benchmark for db4bb6c: fix: support mocking types from extern-…

1fa3cf1

…aliased references (#921) by Valentin Breuß

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fix: support mocking types from extern-aliased references - #921

fix: support mocking types from extern-aliased references#921
vbreuss merged 2 commits into
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fix/extern-alias-types

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