[typemap] Diagnose unsupported export signatures - #12597
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Copilot review overview
🔵 Needs a closer look
Review tier: Lite
Findings: 1
New issues introduced by this change (1)
| Severity | Finding |
|---|---|
 |
src/Microsoft.Android.Sdk.TrimmableTypeMap/Scanner/JavaPeerScanner.cs — |
What changed in this PR
Adds early, localized diagnostics for unsupported [Export] / [ExportField] signature shapes in the trimmable typemap pipeline, so trimmable CoreCLR/NativeAOT fail deterministically (and before emitting typemap/Java/ACW-map outputs) instead of failing later in downstream steps.
Changes:
- Introduces XA4263 (“unsupported export signature type”) during trimmable scanning, while preserving XA4206 precedence for
[Export]on generic declaring types. - Tightens managed→JNI descriptor resolution to support “can we map this?” validation (via
TryManagedTypeToJniDescriptor) without changing the legacy fallback behavior used for signature generation. - Extends unit + integration parity fixtures to cover unsupported shapes and additional supported peer/interface/string-array/stream override cases, and documents XA4263.
| File | Description |
|---|---|
| tests/Microsoft.Android.Sdk.TrimmableTypeMap.Tests/TestFixtures/TestTypes.cs | Adds fixture types covering unsupported [Export]/[ExportField] shapes (managed-only types, generics). |
| tests/Microsoft.Android.Sdk.TrimmableTypeMap.Tests/Generator/TrimmableTypeMapGeneratorTests.cs | Adds generator-level assertions for XA4263/XA4206 and ensures unsupported members aren’t emitted into peers/Java sources. |
| tests/Microsoft.Android.Sdk.TrimmableTypeMap.Tests/Generator/ExportSignatureTests.cs | Adds focused fixture test ensuring unsupported signatures produce no generated members. |
| tests/Microsoft.Android.Sdk.TrimmableTypeMap.IntegrationTests/JavaSourceSemanticParityTests.cs | Extends semantic parity coverage for additional supported method shapes (peer/interface/string-array/stream mapping). |
| tests/Microsoft.Android.Sdk.TrimmableTypeMap.IntegrationTests/JavaSourceParityFixture/JavaSourceParityTypes.cs | Adds new exported members used by the semantic parity fixture (peer, listener, string array, stream mapping). |
| src/Xamarin.Android.Build.Tasks/Tests/Xamarin.Android.Build.Tests/TrimmableTypeMapBuildTests.cs | Adds build-matrix coverage for unsupported export shapes and expands “no partial outputs” checks to include acw-map.txt. |
| src/Xamarin.Android.Build.Tasks/Tasks/GenerateTrimmableTypeMap.cs | Implements new logger hooks for XA4206 and XA4263 in the MSBuild task. |
| src/Xamarin.Android.Build.Tasks/Properties/Resources.resx | Adds localized XA4263 message template. |
| src/Xamarin.Android.Build.Tasks/Properties/Resources.Designer.cs | Adds generated accessor for XA4263 resource. |
| src/Microsoft.Android.Sdk.TrimmableTypeMap/Scanner/JavaPeerScanner.cs | Adds export signature validation and refactors managed→JNI mapping into a Try* API for “supported mapping” checks. |
| src/Microsoft.Android.Sdk.TrimmableTypeMap/ITrimmableTypeMapLogger.cs | Adds logger interface hooks for XA4206 and XA4263. |
| Documentation/docs-mobile/TOC.yml | Wires XA4263 doc into the docs TOC. |
| Documentation/docs-mobile/messages/xa4263.md | Adds documentation for XA4263. |
| Documentation/docs-mobile/messages/index.md | Adds XA4263 to the error code index. |
Files not reviewed (1)
- src/Xamarin.Android.Build.Tasks/Properties/Resources.Designer.cs: Generated file
This was referenced Aug 31, 2026
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Reject unresolved managed, generic, and function-pointer export signatures during trimmable scanning with localized XA4263 diagnostics before any typemap, Java, or ACW-map output is written. Preserve legacy XA4206 precedence and supported Java mappings. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
Honor ExportParameter return mappings on exported fields, reject incompatible special mappings before generation, and resolve Java peer descriptors by assembly identity through type forwarders. Add semantic, cross-assembly, and three-runtime regressions. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
Require special ExportParameter mappings to target exact scalar Stream or XmlReader types, and match Export, ExportParameter, and ExportField attributes by full Java.Interop identity throughout scanner validation and collection. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
Ignore static exported constructors, diagnose unresolved instance constructor parameters without overlapping XA4260 shape ownership, preserve ExportParameter kinds through UCO activation, and resolve enum signatures by assembly identity. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
Ignore Export name overrides on metadata constructors, assert UCO dispatch calls the managed constructor rather than a virtual method, and recursively reserve nested structural parameter shapes for XA4260. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
Require Stream and XmlReader special export mappings to resolve from their framework assemblies or forwarders, preventing same-full-name user types from receiving framework adapters. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
Recognize System.Private.Xml as the canonical XmlReader definition and verify both direct and multi-facade mappings without accepting same-full-name user types. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
Exercise the resolved wrong-assembly branch by indexing a user assembly that defines System.Xml.XmlReader instead of relying on a missing assembly reference. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
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Summary
[Export]/[ExportField]signatures during trimmable scanning with localized XA4263 before typemap, Java, or ACW-map output[ExportParameter]mappingsJava.Interopidentity and resolve peer/enum/special framework types by assembly identity through forwardersFinal type-identity behavior
Special mappings require canonical framework identity, not just a managed full name:
System.IO.Stream:System.Runtimefacade or resolvedSystem.Private.CoreLibSystem.Xml.XmlReader:System.Xml.ReaderWriterfacade or resolvedSystem.Private.Xmlnetstandard → System.Xml.ReaderWriter → System.Private.Xmlare accepted through the existing cycle-safe forwarder resolverTests use minimal metadata assemblies for direct
System.Private.Xml, the two-hop facade chain, and a resolvedUser.Xmlassembly containingSystem.Xml.XmlReader. A separately compiled Android fixture and end-to-end builds retain the user-collision/no-output controls.Constructor diagnostics ownership
PR #12567 owns XA4260 for generic, byref, pointer, function-pointer, rectangular-array constructor parameters, including nested SZ-array forms. XA4263 owns unresolved managed types and invalid
[ExportParameter]kind/type/identity pairs. This PR does not duplicate XA4259/XA4261 analysis.An isolated composition with the latest #12567 reproduces its remaining follow-up: two XA4263-rejected overloads on the same type with default/missing
SuperArgumentsStringalso receive secondary XA4259 and XA4261. The coordinator will make that analyzer skip XA4263-rejected constructors after rebasing #12567 above this PR.Validation
GenerateExportedMembersgit diff --check; every added line at most 180 characters; full-name attribute audit cleanStacked on #12596. Tracks #12561.