Special casing System.Guid for COM VARIANT marshalling
#100377
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VARIANT marshalling in .NET 5+ requires a TLB for COM records (i.e., ValueType instances). This means that without a runtime provided TLB, users must define their own TLB for runtime types or define their own transfer types. We address this here by deferring to the NetFX mscorlib's TLB.
AaronRobinsonMSFT
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Well I've just locally done the refactor to convert VARIANT marshalling to mostly managed yesterday, for the follow up of #100176 |
AaronRobinsonMSFT
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@dotnet/interop-contrib @jkotas I've investigated various COM-RPC scenarios involving boxing and resulting I can't see any risks with this support other than enabling a tricky scenario that has impacted many large enterprise COM based products. |
Co-authored-by: Elinor Fung <elfung@microsoft.com>
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Do we want to add support in source-generated COM as well (as a separate PR, not in this one)? I'd rather not (as implementing it in a portable manner would be very difficult), but I wanted to raise the issue. |
I don't think so. Our model and expectations for the source generated approach seem different. It sounds like you would agree. I think we should look at the entire source generated solution as green field and we should create solutions that are tailored to its design. This is merely an affordance for built-in COM transitions from .NET Framework. |
...pServices.UnitTests/System/Runtime/InteropServices/Marshal/GetNativeVariantForObjectTests.cs
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...ibraries/System.Private.CoreLib/src/System/Runtime/InteropServices/Marshalling/ComVariant.cs
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...ibraries/System.Private.CoreLib/src/System/Runtime/InteropServices/Marshalling/ComVariant.cs
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Co-authored-by: Elinor Fung <elfung@microsoft.com>
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/backport to release/8.0-staging |
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Started backporting to release/8.0-staging: https://github.com/dotnet/runtime/actions/runs/8576746637 |
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@AaronRobinsonMSFT backporting to release/8.0-staging failed, the patch most likely resulted in conflicts: $ git am --3way --ignore-whitespace --keep-non-patch changes.patch
Applying: Support System.Guid marshalling via VARIANT
Applying: Add marshalling of System.Guid in the other direction.
Applying: Adding testing for COM VARIANT marshalling
Applying: Fix contract
Applying: Fix libraries tests
Applying: Apply suggestions from code review
Applying: Review feedback
Applying: Add Guid test for GetObjectForNativeVariant()
Applying: Handle the Nano server case.
Applying: Add test for dynamic scenarios
Using index info to reconstruct a base tree...
A src/libraries/Microsoft.CSharp/src/Microsoft/CSharp/RuntimeBinder/ComInterop/DynamicVariantExtensions.cs
A src/libraries/System.Private.CoreLib/src/System/Runtime/InteropServices/Marshalling/ComVariant.cs
M src/tests/Interop/COM/Dynamic/BasicTest.cs
Falling back to patching base and 3-way merge...
Auto-merging src/tests/Interop/COM/Dynamic/BasicTest.cs
CONFLICT (modify/delete): src/libraries/System.Private.CoreLib/src/System/Runtime/InteropServices/Marshalling/ComVariant.cs deleted in HEAD and modified in Add test for dynamic scenarios. Version Add test for dynamic scenarios of src/libraries/System.Private.CoreLib/src/System/Runtime/InteropServices/Marshalling/ComVariant.cs left in tree.
CONFLICT (modify/delete): src/libraries/Microsoft.CSharp/src/Microsoft/CSharp/RuntimeBinder/ComInterop/DynamicVariantExtensions.cs deleted in HEAD and modified in Add test for dynamic scenarios. Version Add test for dynamic scenarios of src/libraries/Microsoft.CSharp/src/Microsoft/CSharp/RuntimeBinder/ComInterop/DynamicVariantExtensions.cs left in tree.
error: Failed to merge in the changes.
hint: Use 'git am --show-current-patch=diff' to see the failed patch
Patch failed at 0010 Add test for dynamic scenarios
When you have resolved this problem, run "git am --continue".
If you prefer to skip this patch, run "git am --skip" instead.
To restore the original branch and stop patching, run "git am --abort".
Error: The process '/usr/bin/git' failed with exit code 128Please backport manually! |
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@AaronRobinsonMSFT an error occurred while backporting to release/8.0-staging, please check the run log for details! Error: git am failed, most likely due to a merge conflict. |
* Support System.Guid marshalling via VARIANT VARIANT marshalling in .NET 5+ requires a TLB for COM records (i.e., ValueType instances). This means that without a runtime provided TLB, users must define their own TLB for runtime types or define their own transfer types. We address this here by deferring to the NetFX mscorlib's TLB. Co-authored-by: Elinor Fung <elfung@microsoft.com>
* Support System.Guid marshalling via VARIANT VARIANT marshalling in .NET 5+ requires a TLB for COM records (i.e., ValueType instances). This means that without a runtime provided TLB, users must define their own TLB for runtime types or define their own transfer types. We address this here by deferring to the NetFX mscorlib's TLB. Co-authored-by: Elinor Fung <elfung@microsoft.com>
The majority of the PR contains tests changes.
This is a basic proposal for how marshalling of
System.Guidcould be supported for those porting from .NET Framework to .NET 8+. This PR also adds testing for the most basicVARIANTscenarios that would be supported.At present, marshalling of any .NET provided value type is difficult since .NET doesn't provide a TLB. This means that common "primitive" types like
System.Guidcan't be marshalled in anVARIANT(that is,object)./cc @dotnet/interop-contrib @jkotas