bugfix: fix incorrect dynamic array marshalling by ODtian · Pull Request #70 · MikhailGorobets/Diligent-SharpGenTools

ODtian · 2026-02-18T08:42:22Z

Related: DiligentGraphics/DiligentCore#766

Root Cause & Context:
When a user configures <map override-native-type="true" /> for an array field (e.g., mapping byte[] to a different native type), two cascading issues occur:

Incorrect Marshaller Selection: RemappedTypeMarshaller incorrectly claimed responsibility for the field. Since it lacks array handling capabilities, it generated code that completely missed the array marshalling logic.
Defective Dynamic Array Logic: Even when ValueTypeArrayMarshaller was correctly forced to handle the field, its implementation for Dynamic Arrays was flawed:
- Memory Corruption: It reused GenerateCopyMemory (designed for Constant Arrays), which unconditionally took the address of the target field (&@ref.Ptr). For dynamic arrays (which are pointers), this caused the marshaller to overwrite the pointer variable itself and adjacent struct fields (e.g., array length), leading to Access Violations.
- Missing Logic: It failed to generate code to assign the managed array's length to the native struct's length field (defined by LengthRelation), leaving the native API with a zero or uninitialized length.

Fix:

Correct Marshaller Routing:
- Modified RemappedTypeMarshaller.CanMarshal to explicitly exclude array types, preventing incorrect interception.
- Modified ValueTypeArrayMarshaller.CanMarshal to allow handling of fields that are mapped to different public types (MappedToDifferentPublicType).
Fix Memory Corruption:
- Refactored GenerateCopyMemory to accept a bool takeAddress parameter.
- For Dynamic Arrays, passed takeAddress = false to use the pointer directly as the destination, bypassing the incorrect address-taking.
Complete Length Assignment:
- Added the missing logic to assign the array length to the corresponding native length field (based on ArraySpecification) during dynamic array marshalling.

MikhailGorobets · 2026-02-18T09:10:35Z

@ODtian Unit tests are failing

Copilot

Pull request overview

Fixes incorrect codegen for dynamic array marshalling when an array field is remapped via override-native-type="true" (issue #766), ensuring the correct marshaller is selected and preventing pointer/length field corruption during managed→native copies.

Changes:

Prevent RemappedTypeMarshaller from intercepting array types; allow ValueTypeArrayMarshaller to handle value-type arrays even when remapped.
Refactor ValueTypeArrayMarshaller.GenerateCopyMemory to optionally avoid taking the address of the native destination for dynamic arrays.
Add missing dynamic-array length assignment to the related native length field during managed→native marshalling.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
SharpGen/Generator/Marshallers/ValueTypeArrayMarshaller.cs	Routes remapped value-type arrays to this marshaller and adds dynamic-array length assignment; uses `takeAddress:false` for managed→native dynamic copies.
SharpGen/Generator/Marshallers/ValueTypeArrayMarshaller.Copy.cs	Refactors copy helper to optionally skip address-of on the native side.
SharpGen/Generator/Marshallers/RemappedTypeMarshaller.cs	Stops remapped-type marshaller from claiming array marshalling.

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Copilot · 2026-02-18T09:16:30Z

SharpGen/Generator/Marshallers/ValueTypeArrayMarshaller.cs

                                MemberAccessExpression(SyntaxKind.SimpleMemberAccessExpression, IdentifierName(MarshalParameterRefName), IdentifierName(csElement.Name)),
                                ParseExpression($"({csElement.PublicType.QualifiedName}*)System.Runtime.InteropServices.NativeMemory.Alloc((nuint) (System.Runtime.CompilerServices.Unsafe.SizeOf<{csElement.PublicType.QualifiedName}>() * {csElement.Name}.Length))"))), 
-                         GenerateCopyMemory(csElement, ArrayCopyDirection.ManagedToNative)
+                          GenerateCopyMemory(csElement, ArrayCopyDirection.ManagedToNative, takeAddress: false),
+                          ExpressionStatement(AssignmentExpression(SyntaxKind.SimpleAssignmentExpression, MemberAccessExpression(SyntaxKind.SimpleMemberAccessExpression, IdentifierName(MarshalParameterRefName), IdentifierName(csElement.ArraySpecification?.SizeIdentifier)), ParseExpression($"({csElement.ArraySpecification?.TypeSizeIdentifier}){csElement.Name}.Length")))


GenerateCopyMemory(..., takeAddress: false) is applied for the dynamic-array Managed→Native path, but the dynamic-array Native→Managed path still calls GenerateCopyMemory(csElement, ArrayCopyDirection.NativeToManaged) with the default takeAddress=true. Since GetMarshalStorageLocation(csElement) is a pointer field for dynamic arrays, taking its address yields a T** and will copy from/to the pointer variable itself rather than the pointed-to array. Pass takeAddress: false for the dynamic Native→Managed case as well (and consider restricting takeAddress based on ArraySpecificationType.Dynamic inside GenerateCopyMemory to avoid future call-site mistakes).

Copilot · 2026-02-18T09:16:33Z

SharpGen/Generator/Marshallers/ValueTypeArrayMarshaller.cs

            CsField { ArraySpecification.Type: ArraySpecificationType.Dynamic } =>
                 IfStatement(BinaryExpression(SyntaxKind.GreaterThanExpression, GeneratorHelpers.NullableLengthExpression(IdentifierName(csElement.Name)), ZeroLiteral),
                     Block(
                          ExpressionStatement(
                            AssignmentExpression(SyntaxKind.SimpleAssignmentExpression,
                                MemberAccessExpression(SyntaxKind.SimpleMemberAccessExpression, IdentifierName(MarshalParameterRefName), IdentifierName(csElement.Name)),
                                ParseExpression($"({csElement.PublicType.QualifiedName}*)System.Runtime.InteropServices.NativeMemory.Alloc((nuint) (System.Runtime.CompilerServices.Unsafe.SizeOf<{csElement.PublicType.QualifiedName}>() * {csElement.Name}.Length))"))), 
-                         GenerateCopyMemory(csElement, ArrayCopyDirection.ManagedToNative)
+                          GenerateCopyMemory(csElement, ArrayCopyDirection.ManagedToNative, takeAddress: false),
+                          ExpressionStatement(AssignmentExpression(SyntaxKind.SimpleAssignmentExpression, MemberAccessExpression(SyntaxKind.SimpleMemberAccessExpression, IdentifierName(MarshalParameterRefName), IdentifierName(csElement.ArraySpecification?.SizeIdentifier)), ParseExpression($"({csElement.ArraySpecification?.TypeSizeIdentifier}){csElement.Name}.Length")))


This change introduces new dynamic-array behavior for value-type arrays when the element type is remapped (MappedToDifferentPublicType) and adds length-field assignment during marshalling. There doesn't appear to be an integration test covering a struct field dynamic array with override-native-type="true" + length(...) (e.g., PointerSizeMemberExtended::byteCode in SdkTests/Struct/Mapping.xml). Adding an SdkTests/Struct test that exercises round-tripping (pointer + length) would help prevent regressions like the reported memory corruption and missing length assignment.

ODtian · 2026-02-18T09:33:21Z

@ODtian Unit tests are failing

The tests pass successfully on my local machine. I suspect this is caused by a misconfiguration in the GitHub Actions workflow, as the output seems to indicate that the .NET 6.0 environment is missing. 🥲

Testhost process for source(s) 'D:\a\Diligent-SharpGenTools\Diligent-SharpGenTools\SharpGen.UnitTests\bin\Release\net6.0\SharpGen.UnitTests.dll' exited with error: You must install or update .NET to run this application.
App: D:\a\Diligent-SharpGenTools\Diligent-SharpGenTools\SharpGen.UnitTests\bin\Release\net6.0\testhost.exe
Architecture: x64
Framework: 'Microsoft.NETCore.App', version '6.0.0' (x64)
.NET location: C:\Program Files\dotnet
The following frameworks were found:
  8.0.6 at [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  8.0.22 at [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  8.0.23 at [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  9.0.6 at [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  9.0.12 at [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  10.0.2 at [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
The following frameworks for other architectures were found:
  x86
    8.0.23 at [C:\Program Files (x86)\dotnet\shared\Microsoft.NETCore.App]
    9.0.12 at [C:\Program Files (x86)\dotnet\shared\Microsoft.NETCore.App]
Learn more:
https://aka.ms/dotnet/app-launch-failed
To install missing framework, download:
https://aka.ms/dotnet-core-applaunch?framework=Microsoft.NETCore.App&framework_version=6.0.0&arch=x64&rid=win-x64&os=win10
. Please check the diagnostic logs for more information.
Results File: D:\a\Diligent-SharpGenTools\Diligent-SharpGenTools/artifacts/test-results/UnitTests.trx

Test Run Aborted.
Write-Error: D:\a\_temp\36b38049-476c-453f-8eee-1d7380766f74.ps1:2
Line |
   2 |  ./build.ps1 -Configuration Release
     |  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     | Unit Tests Failed
Error: Process completed with exit code 1.

MikhailGorobets · 2026-02-18T09:40:09Z

@ODtian Unit tests are failing

The tests pass successfully on my local machine. I suspect this is caused by a misconfiguration in the GitHub Actions workflow, as the output seems to indicate that the .NET 6.0 environment is missing. 🥲

Testhost process for source(s) 'D:\a\Diligent-SharpGenTools\Diligent-SharpGenTools\SharpGen.UnitTests\bin\Release\net6.0\SharpGen.UnitTests.dll' exited with error: You must install or update .NET to run this application.
App: D:\a\Diligent-SharpGenTools\Diligent-SharpGenTools\SharpGen.UnitTests\bin\Release\net6.0\testhost.exe
Architecture: x64
Framework: 'Microsoft.NETCore.App', version '6.0.0' (x64)
.NET location: C:\Program Files\dotnet
The following frameworks were found:
  8.0.6 at [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  8.0.22 at [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  8.0.23 at [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  9.0.6 at [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  9.0.12 at [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  10.0.2 at [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
The following frameworks for other architectures were found:
  x86
    8.0.23 at [C:\Program Files (x86)\dotnet\shared\Microsoft.NETCore.App]
    9.0.12 at [C:\Program Files (x86)\dotnet\shared\Microsoft.NETCore.App]
Learn more:
https://aka.ms/dotnet/app-launch-failed
To install missing framework, download:
https://aka.ms/dotnet-core-applaunch?framework=Microsoft.NETCore.App&framework_version=6.0.0&arch=x64&rid=win-x64&os=win10
. Please check the diagnostic logs for more information.
Results File: D:\a\Diligent-SharpGenTools\Diligent-SharpGenTools/artifacts/test-results/UnitTests.trx

Test Run Aborted.
Write-Error: D:\a\_temp\36b38049-476c-453f-8eee-1d7380766f74.ps1:2
Line |
   2 |  ./build.ps1 -Configuration Release
     |  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     | Unit Tests Failed
Error: Process completed with exit code 1.

@ODtian Unit tests are failing

The tests pass successfully on my local machine. I suspect this is caused by a misconfiguration in the GitHub Actions workflow, as the output seems to indicate that the .NET 6.0 environment is missing. 🥲

Testhost process for source(s) 'D:\a\Diligent-SharpGenTools\Diligent-SharpGenTools\SharpGen.UnitTests\bin\Release\net6.0\SharpGen.UnitTests.dll' exited with error: You must install or update .NET to run this application.
App: D:\a\Diligent-SharpGenTools\Diligent-SharpGenTools\SharpGen.UnitTests\bin\Release\net6.0\testhost.exe
Architecture: x64
Framework: 'Microsoft.NETCore.App', version '6.0.0' (x64)
.NET location: C:\Program Files\dotnet
The following frameworks were found:
  8.0.6 at [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  8.0.22 at [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  8.0.23 at [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  9.0.6 at [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  9.0.12 at [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
  10.0.2 at [C:\Program Files\dotnet\shared\Microsoft.NETCore.App]
The following frameworks for other architectures were found:
  x86
    8.0.23 at [C:\Program Files (x86)\dotnet\shared\Microsoft.NETCore.App]
    9.0.12 at [C:\Program Files (x86)\dotnet\shared\Microsoft.NETCore.App]
Learn more:
https://aka.ms/dotnet/app-launch-failed
To install missing framework, download:
https://aka.ms/dotnet-core-applaunch?framework=Microsoft.NETCore.App&framework_version=6.0.0&arch=x64&rid=win-x64&os=win10
. Please check the diagnostic logs for more information.
Results File: D:\a\Diligent-SharpGenTools\Diligent-SharpGenTools/artifacts/test-results/UnitTests.trx

Test Run Aborted.
Write-Error: D:\a\_temp\36b38049-476c-453f-8eee-1d7380766f74.ps1:2
Line |
   2 |  ./build.ps1 -Configuration Release
     |  ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
     | Unit Tests Failed
Error: Process completed with exit code 1.

Try adding a .NET 6.0 setup step to the CI (it’s also possible to update the configuration files to the latest .NET version supported by GitHub Actions, but I think that would take a lot of time).

MikhailGorobets · 2026-02-18T09:46:49Z

There’s also another version of these bindings, but I haven’t tried it
https://github.com/rbnpontes/DiligentEngineNET

ODtian · 2026-02-18T10:22:53Z

There’s also another version of these bindings, but I haven’t tried it https://github.com/rbnpontes/DiligentEngineNET

Thanks for mentioning it, but the project doesn't seem to be officially supported or actively maintained. 😭

BTW, can you approve the awaiting action request? Thanks!

MikhailGorobets · 2026-02-18T11:42:30Z

There’s also another version of these bindings, but I haven’t tried it https://github.com/rbnpontes/DiligentEngineNET

Thanks for mentioning it, but the project doesn't seem to be officially supported or actively maintained. 😭

BTW, can you approve the awaiting action request? Thanks!

Could you also add a unit test for the case where the error occurred? (Also, please make the commit titles consistent with this repository’s commit history.)

MikhailGorobets requested a review from Copilot February 18, 2026 09:07

Copilot started reviewing on behalf of MikhailGorobets February 18, 2026 09:07 View session

Copilot AI reviewed Feb 18, 2026

View reviewed changes

ODtian force-pushed the main branch from 1c70b13 to 4d2e96a Compare February 18, 2026 10:11

ODtian added 2 commits February 18, 2026 20:29

Fixed dynamic array marshalling

2112ba5

Added dotnet6 environment in github actions and build scripts

776f6d2

ODtian force-pushed the main branch from 4d2e96a to 776f6d2 Compare February 18, 2026 12:31

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bugfix: fix incorrect dynamic array marshalling#70

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