[bgen] Propagate nullability information for generic type arguments. Fixes #16860#25541
[bgen] Propagate nullability information for generic type arguments. Fixes #16860#25541rolfbjarne wants to merge 8 commits into
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…ixes #16860. When a property has a generic type like Action<NSObject?, NSError?>, the C# compiler emits a [NullableAttribute(byte[])] where each byte encodes the nullability for the outer type and each generic argument in depth-first order. Previously, bgen only looked at the first byte (the outer type) and ignored nullability for generic type arguments. This change: - Adds GetNullabilityBytes() to AttributeManager to extract the full byte array - Adds a FormatType overload in TypeManager that processes the byte array to annotate each generic type argument with ? where appropriate - Uses the new method when rendering property type declarations Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
…onsumption. - Use braces for all if/else/for blocks in new code. - Add complex test samples with many generic args, value types, and alternating nullability patterns. - Fix bug where value types incorrectly consumed nullability bytes. - Only apply nullability for void-returning delegates (Action<>) in the non-wrap path to avoid Func<> covariance issues with trampolines. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
…tead. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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🔥 [CI Build #c698bc8] Test results 🔥Test results❌ Tests failed on VSTS: test results 29 tests crashed, 0 tests failed, 0 tests passed. Failures❌ cecil tests🔥 Failed catastrophically on VSTS: test results - cecil (no summary found). Html Report (VSDrops) Download ❌ dotnettests tests (iOS)🔥 Failed catastrophically on VSTS: test results - dotnettests_ios (no summary found). Html Report (VSDrops) Download ❌ dotnettests tests (MacCatalyst)🔥 Failed catastrophically on VSTS: test results - dotnettests_maccatalyst (no summary found). Html Report (VSDrops) Download ❌ dotnettests tests (macOS)🔥 Failed catastrophically on VSTS: test results - dotnettests_macos (no summary found). Html Report (VSDrops) Download ❌ dotnettests tests (Multiple platforms)🔥 Failed catastrophically on VSTS: test results - dotnettests_multiple (no summary found). Html Report (VSDrops) Download ❌ dotnettests tests (tvOS)🔥 Failed catastrophically on VSTS: test results - dotnettests_tvos (no summary found). Html Report (VSDrops) Download ❌ framework tests🔥 Failed catastrophically on VSTS: test results - framework (no summary found). Html Report (VSDrops) Download ❌ fsharp tests🔥 Failed catastrophically on VSTS: test results - fsharp (no summary found). Html Report (VSDrops) Download ❌ generator tests🔥 Failed catastrophically on VSTS: test results - generator (no summary found). Html Report (VSDrops) Download ❌ interdependent-binding-projects tests🔥 Failed catastrophically on VSTS: test results - interdependent-binding-projects (no summary found). Html Report (VSDrops) Download ❌ introspection tests🔥 Failed catastrophically on VSTS: test results - introspection (no summary found). Html Report (VSDrops) Download ❌ linker tests (iOS)🔥 Failed catastrophically on VSTS: test results - linker_ios (no summary found). Html Report (VSDrops) Download ❌ linker tests (MacCatalyst)🔥 Failed catastrophically on VSTS: test results - linker_maccatalyst (no summary found). Html Report (VSDrops) Download ❌ linker tests (macOS)🔥 Failed catastrophically on VSTS: test results - linker_macos (no summary found). Html Report (VSDrops) Download ❌ linker tests (tvOS)🔥 Failed catastrophically on VSTS: test results - linker_tvos (no summary found). Html Report (VSDrops) Download ❌ monotouch tests (iOS)🔥 Failed catastrophically on VSTS: test results - monotouch_ios (no summary found). Html Report (VSDrops) Download ❌ monotouch tests (MacCatalyst)🔥 Failed catastrophically on VSTS: test results - monotouch_maccatalyst (no summary found). Html Report (VSDrops) Download ❌ monotouch tests (macOS)🔥 Failed catastrophically on VSTS: test results - monotouch_macos (no summary found). Html Report (VSDrops) Download ❌ monotouch tests (tvOS)🔥 Failed catastrophically on VSTS: test results - monotouch_tvos (no summary found). Html Report (VSDrops) Download ❌ msbuild tests🔥 Failed catastrophically on VSTS: test results - msbuild (no summary found). Html Report (VSDrops) Download ❌ sharpie tests🔥 Failed catastrophically on VSTS: test results - sharpie (no summary found). Html Report (VSDrops) Download ❌ windows tests🔥 Failed catastrophically on VSTS: test results - windows (no summary found). Html Report (VSDrops) Download ❌ xcframework tests🔥 Failed catastrophically on VSTS: test results - xcframework (no summary found). Html Report (VSDrops) Download ❌ xtro tests🔥 Failed catastrophically on VSTS: test results - xtro (no summary found). Html Report (VSDrops) Download ❌ Tests on macOS Monterey (12) tests🔥 Failed catastrophically on VSTS: test results - mac_monterey (no summary found). Html Report (VSDrops) Download ❌ Tests on macOS Ventura (13) tests🔥 Failed catastrophically on VSTS: test results - mac_ventura (no summary found). Html Report (VSDrops) Download ❌ Tests on macOS Sonoma (14) tests🔥 Failed catastrophically on VSTS: test results - mac_sonoma (no summary found). Html Report (VSDrops) Download ❌ Tests on macOS Sequoia (15) tests🔥 Failed catastrophically on VSTS: test results - mac_sequoia (no summary found). Html Report (VSDrops) Download ❌ Tests on macOS Tahoe (26) tests🔥 Failed catastrophically on VSTS: test results - mac_tahoe (no summary found). Html Report (VSDrops) Download SuccessesmacOS testsLinux Build VerificationPipeline on Agent |
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Summary
When properties have generic delegate types (like
Action<NSObject?, NSError?>), bgen now correctly propagates the?nullability annotations on the generic type arguments in the generated C# code.Previously, bgen only read the first byte of the
[NullableAttribute(byte[])]array (for the outer type's nullability), ignoring the remaining bytes that encode nullability for generic type arguments. This caused properties likeAction<UIViewController?, NSError?>to be rendered asAction<UIViewController, NSError>— losing the nullability annotations.Changes
src/bgen/AttributeManager.cs: AddedGetNullabilityBytes()method that extracts the full byte array from[NullableAttribute].src/bgen/TypeManager.cs: AddedFormatType(Type?, Type?, byte[]?)overload and a recursiveFormatTypeUsedInhelper that consumes nullability bytes in depth-first traversal order, correctly skipping value types (which don't have bytes in the array).src/bgen/Generator.cs: Updated property rendering to pass nullability bytes. The "wrap" path applies nullability for all delegate types. The "non-wrap" path only applies for void-returning delegates (Action<>) to avoidFunc<>covariance issues with trampoline signatures.tests/bgen/BGenTests.cs: AddedGenericTypeNullabilitytest with 10 assertions.tests/bgen/tests/generic-type-nullability.cs: Test input covering nullable args, non-nullable args, value types, many args, mixed patterns, and alternating nullability.Key design decisions
NullableAttributearray. The fix correctly identifies value types and skips them during traversal.Func<>covariance guard: Trampolines use non-nullable generic args. This is fine forAction<in T>(contravariant) but breaks forFunc<out T>(covariant). The non-wrap path only applies nullability for void-returning delegates.Fixes #16860
🤖 Pull request created by Copilot