[cDAC] Return E_FAIL when module metadata is unavailable#130904
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When a module's metadata is unavailable, several ISOS/IXCLRData/DacDbi COM methods relied on a null-forgiving MetadataReader (GetMetadata(...)!), which surfaced as a NullReferenceException (E_POINTER) rather than the E_FAIL the native DAC returns. Return E_FAIL at the high-confidence COM-boundary sites where the enclosing method already catches exceptions and returns ex.HResult, and where the native DAC returns E_FAIL when metadata is unavailable: - IXCLRDataModule.StartEnumMethodDefinitionsByName - ISOSDacInterface.GetFieldDescData - DacDbi GetObjectFields (enclosing-class metadata resolution) The metadata read now throws Marshal.GetExceptionForHR(HResults.E_FAIL) when GetMetadata returns null. Signature formatting / type-name building (SigFormat, TypeNameBuilder), the ClrDataFrame local-signature reader (whose null result is converted to a DEFAULT value flag), and the contract-layer metadata reads are intentionally left unchanged to keep this change to well-understood COM boundaries. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com> Copilot-Session: f2aa5dc4-0c99-43f0-af14-734143849c4a
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Tagging subscribers to this area: @steveisok, @tommcdon, @dotnet/dotnet-diag |
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Pull request overview
This PR aligns several cDAC COM-boundary implementations with native DAC behavior by returning E_FAIL (instead of surfacing NullReferenceException / E_POINTER) when module metadata cannot be obtained, and adds a targeted regression test for the IXCLRDataModule.StartEnumMethodDefinitionsByName scenario.
Changes:
- Replace null-forgiving
GetMetadata(... )!usages at selected COM boundaries with?? throw Marshal.GetExceptionForHR(HResults.E_FAIL)!so the enclosingcatch (Exception ex) { return ex.HResult; }paths returnE_FAIL. - Apply the same missing-metadata handling in
ISOSDacInterface.GetFieldDescDataand DacDbiGetObjectFields(enclosing-class metadata resolution). - Add a unit test validating
StartEnumMethodDefinitionsByNamereturnsE_FAILwhenIEcmaMetadata.GetMetadatareturnsnull.
Reviewed changes
Copilot reviewed 4 out of 4 changed files in this pull request and generated 1 comment.
| File | Description |
|---|---|
| src/native/managed/cdac/tests/UnitTests/ClrDataModuleMetadataTests.cs | Adds a regression test for IXCLRDataModule.StartEnumMethodDefinitionsByName when metadata is unavailable. |
| src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Legacy/ClrDataModule.cs | Returns E_FAIL for missing module metadata in StartEnumMethodDefinitionsByName by throwing an E_FAIL-HResult exception. |
| src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Legacy/SOSDacImpl.cs | Returns E_FAIL (instead of NRE/E_POINTER) when GetMetadata returns null in GetFieldDescData. |
| src/native/managed/cdac/Microsoft.Diagnostics.DataContractReader.Legacy/Dbi/DacDbiImpl.cs | Returns E_FAIL when enclosing-type metadata is unavailable in GetObjectFields. |
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| private static readonly MockTarget.Architecture s_arch = new() { IsLittleEndian = true, Is64Bit = true }; | ||
| private static readonly TargetPointer s_modulePointer = new(0x1000); | ||
| private static readonly ModuleHandle s_moduleHandle = new(new TargetPointer(0x2000)); | ||
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| [Fact] | ||
| public void StartEnumMethodDefinitionsByName_MissingMetadataReturnsEFail() | ||
| { | ||
| var loader = new Mock<ILoader>(); | ||
| loader.Setup(l => l.GetModuleHandleFromModulePtr(s_modulePointer)).Returns(s_moduleHandle); | ||
| var ecmaMetadata = new Mock<IEcmaMetadata>(); | ||
| ecmaMetadata.Setup(e => e.GetMetadata(s_moduleHandle)).Returns((MetadataReader?)null); | ||
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| TestPlaceholderTarget target = new TestPlaceholderTarget.Builder(s_arch) | ||
| .UseReader((ulong _, Span<byte> _) => -1) | ||
| .AddMockContract(loader) | ||
| .AddMockContract(ecmaMetadata) | ||
| .Build(); |
max-charlamb
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We should remove the null forgiving operator usage on the other GetMetadata calls as well. The goal is to make the error more clear if the method returns null.
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This test isn't important; we don't need to match the native error codes exactly. Let's remove it.
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Summary
When a module's metadata is unavailable, several
ISOS/IXCLRData/DacDbi COMmethods relied on a null-forgiving
MetadataReader(GetMetadata(...)!), whichsurfaced as a
NullReferenceException(E_POINTER) instead of theE_FAILthenative DAC returns.
Native semantic parity
At the high-confidence COM-boundary sites -- where the enclosing method already
catches exceptions and returns
ex.HResult, and the native DAC returnsE_FAILfor missing metadata -- the metadata read now throws
Marshal.GetExceptionForHR(HResults.E_FAIL)whenGetMetadatareturns null:IXCLRDataModule.StartEnumMethodDefinitionsByNameISOSDacInterface.GetFieldDescDataGetObjectFields(enclosing-class metadata resolution)Scope
To keep this change to well-understood COM boundaries, the following are
intentionally left unchanged:
SigFormat,TypeNameBuilder).ClrDataFramelocal-signature reader, whose null result is converted to aDEFAULTvalue flag rather than surfaced as an error.Signature_1,RuntimeTypeSystem_1) metadata reads.Testing
ClrDataModuleMetadataTests.StartEnumMethodDefinitionsByName_MissingMetadataReturnsEFail-- asserts the COM method returns
E_FAIL(notE_POINTER/InvalidOperationException) when metadata is unavailable.Note
This PR was generated with the assistance of GitHub Copilot.