[tools/msbuild] Add support for mergeable libraries. Fixes #20262. by rolfbjarne · Pull Request #24710 · dotnet/macios

rolfbjarne · 2026-02-13T15:11:20Z

WIP WIP WIP.

Fixes #20262.

Add support for detecting and stripping mergeable library metadata (LC_ATOM_INFO) from frameworks embedded in app bundles. Mergeable libraries are dylibs/frameworks built with -make_mergeable that contain extra static linking metadata, roughly doubling their size. When used as dynamic libraries, this metadata is unnecessary. Changes: - Add LC_ATOM_INFO (0x36) to LoadCommands enum in MachO.cs - Add HasAtomInfo property and IsMergeableLibrary() method for detection - Add -no_atom_info flag to SymbolStrip task when stripping frameworks - Add tests for detection and stripping of mergeable libraries Fixes #20262

Add a new StripMergeableLibraries MSBuild property that controls whether LC_ATOM_INFO (mergeable library metadata) is stripped from frameworks during symbol stripping. The property defaults to the value of Optimize, so Release builds strip the metadata (reducing app size) while Debug builds preserve it. Changes: - SymbolStrip task: add StripMergeableLibraries property, conditionally pass -no_atom_info to strip. - Xamarin.Shared.props: define StripMergeableLibraries defaulting to Optimize. - Xamarin.Shared.targets: pass StripMergeableLibraries to SymbolStrip. - test-libraries: add XMergeableTest framework built with -Wl,-make_mergeable, including plists for all RIDs. - NativeMergeableFrameworkReferencesApp: test app that references the mergeable framework. - ProjectTest.cs: add test cases for building the mergeable framework app and verifying atom info stripping behavior. - MergeableLibraryTests.cs: add test for preserving atom info when StripMergeableLibraries is false.

Add a binding project that embeds the XMergeableTest mergeable framework, with pack tests verifying the nupkg contains the framework correctly. - bindings-framework-test/dotnet-mergeable: binding project referencing XMergeableTest.framework with IsBindingProject=true. - PackTest.cs: BindingMergeableFrameworksProject test verifying dotnet pack produces correct nupkg structure with the mergeable framework. - ProjectTest.cs: BuildNativeMergeableFrameworkReferencesApp_AtomInfoStripping test verifying atom info is stripped when Optimize=true and preserved when Optimize=false.

Add a new StripMergeableLibraryMetadata MSBuild task and target that strips LC_ATOM_INFO from frameworks in the app bundle. This runs independently of the regular symbol stripping (_NativeStripFiles), which is disabled for simulator builds, debug builds, and macOS/MacCatalyst. The new task: - Scans the app bundle's Frameworks directory for .framework directories - Checks each framework executable with MachO.IsMergeableLibrary() - Only strips frameworks that actually have LC_ATOM_INFO - Runs strip -no_atom_info on matching frameworks This ensures mergeable library metadata is stripped when StripMergeableLibraries=true (i.e. Optimize=true), regardless of whether NoSymbolStrip is enabled.

- Remove RuntimeIdentifier from NativeMergeableFrameworkReferencesApp platform projects (default values are chosen automatically). - Add NativeMergeableDylibReferencesApp test app referencing a standalone mergeable dylib (libMergeableFramework.dylib). - Add libMergeableFramework.dylib build rule in test-libraries Makefile. - Extend StripMergeableLibraryMetadata task to also scan dylib directories (e.g. MonoBundle) for mergeable libraries. - Add BuildNativeMergeableDylibReferencesApp_AtomInfoStripping test verifying dylib atom info stripping behavior. All 8 integration tests and 10 unit tests pass.

…braries

The XMergeableTest framework is always packaged as a .resources.zip in the nupkg, regardless of platform. Remove the per-platform symlink check that incorrectly expected individual files for iOS and tvOS.

msbuild/Xamarin.Shared/Xamarin.Shared.props

tests/dotnet/UnitTests/PackTest.cs

tests/msbuild/Xamarin.MacDev.Tasks.Tests/TaskTests/MergeableLibraryTests.cs

- Document StripMergeableLibraries property in build-properties.md - Remove [Category ("Multiplatform")] from BindingMergeableFrameworksProject test - Replace custom RunProcess with ExecutionHelper in MergeableLibraryTests

vs-mobiletools-engineering-service2 · 2026-02-19T11:49:12Z

✅ [CI Build #1a5150c] Build passed (Build packages) ✅

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vs-mobiletools-engineering-service2 · 2026-02-19T11:52:46Z

✅ [PR Build #1a5150c] Build passed (Detect API changes) ✅

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vs-mobiletools-engineering-service2 · 2026-02-19T12:30:14Z

✅ API diff for current PR / commit

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iOS: vsdrops gist ( No breaking changes )
tvOS: vsdrops gist ( No breaking changes )
MacCatalyst: vsdrops gist ( No breaking changes )
macOS: vsdrops gist ( No breaking changes )

✅ API diff vs stable

NET (empty diffs)

iOS: vsdrops gist ( No breaking changes )
tvOS: vsdrops gist ( No breaking changes )
MacCatalyst: vsdrops gist ( No breaking changes )
macOS: vsdrops gist ( No breaking changes )

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vs-mobiletools-engineering-service2 · 2026-02-19T12:47:50Z

✅ [CI Build #1a5150c] Build passed (Build macOS tests) ✅

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vs-mobiletools-engineering-service2 · 2026-02-19T12:56:23Z

💻 [CI Build #1a5150c] Tests on macOS X64 - Mac Sonoma (14) passed 💻

✅ All tests on macOS X64 - Mac Sonoma (14) passed.

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vs-mobiletools-engineering-service2 · 2026-02-19T13:01:02Z

💻 [CI Build #1a5150c] Tests on macOS M1 - Mac Monterey (12) passed 💻

✅ All tests on macOS M1 - Mac Monterey (12) passed.

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vs-mobiletools-engineering-service2 · 2026-02-19T13:02:11Z

💻 [CI Build #1a5150c] Tests on macOS M1 - Mac Ventura (13) passed 💻

✅ All tests on macOS M1 - Mac Ventura (13) passed.

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vs-mobiletools-engineering-service2 · 2026-02-19T13:02:30Z

💻 [CI Build #1a5150c] Tests on macOS arm64 - Mac Tahoe (26) passed 💻

✅ All tests on macOS arm64 - Mac Tahoe (26) passed.

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vs-mobiletools-engineering-service2 · 2026-02-19T13:03:09Z

💻 [CI Build #1a5150c] Tests on macOS arm64 - Mac Sequoia (15) passed 💻

✅ All tests on macOS arm64 - Mac Sequoia (15) passed.

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vs-mobiletools-engineering-service2 · 2026-02-19T13:15:46Z

🔥 [CI Build #1a5150c] Test results 🔥

Test results

❌ Tests failed on VSTS: test results

0 tests crashed, 3 tests failed, 128 tests passed.

Failures

❌ linker tests

3 tests failed, 41 tests passed.

Failed tests

link all/iOS - simulator/Release: LaunchFailure
trimmode copy/iOS - simulator/Release: LaunchFailure
trimmode link/iOS - simulator/Debug: LaunchFailure

Html Report (VSDrops) Download

Successes

✅ cecil: All 1 tests passed. Html Report (VSDrops) Download
✅ dotnettests (iOS): All 1 tests passed. Html Report (VSDrops) Download
✅ dotnettests (MacCatalyst): All 1 tests passed. Html Report (VSDrops) Download
✅ dotnettests (macOS): All 1 tests passed. Html Report (VSDrops) Download
✅ dotnettests (Multiple platforms): All 1 tests passed. Html Report (VSDrops) Download
✅ dotnettests (tvOS): All 1 tests passed. Html Report (VSDrops) Download
✅ framework: All 2 tests passed. Html Report (VSDrops) Download
✅ fsharp: All 4 tests passed. Html Report (VSDrops) Download
✅ generator: All 5 tests passed. Html Report (VSDrops) Download
✅ interdependent-binding-projects: All 4 tests passed. Html Report (VSDrops) Download
✅ introspection: All 6 tests passed. Html Report (VSDrops) Download
✅ monotouch (iOS): All 11 tests passed. Html Report (VSDrops) Download
✅ monotouch (MacCatalyst): All 15 tests passed. Html Report (VSDrops) Download
✅ monotouch (macOS): All 12 tests passed. Html Report (VSDrops) Download
✅ monotouch (tvOS): All 11 tests passed. Html Report (VSDrops) Download
✅ msbuild: All 2 tests passed. Html Report (VSDrops) Download
✅ sharpie: All 1 tests passed. Html Report (VSDrops) Download
✅ windows: All 3 tests passed. Html Report (VSDrops) Download
✅ xcframework: All 4 tests passed. Html Report (VSDrops) Download
✅ xtro: All 1 tests passed. Html Report (VSDrops) Download

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rolfbjarne and others added 4 commits February 12, 2026 17:25

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rolfbjarne added the copilot label Feb 16, 2026

rolfbjarne added 4 commits February 17, 2026 11:21

[tests] Use arm64 runtime identifiers in mergeable library tests

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Merge remote-tracking branch 'origin/main' into dev/rolf/mergeable-li…

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[tests] Fix BindingMergeableFrameworksProject nupkg content assertions

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The XMergeableTest framework is always packaged as a .resources.zip in the nupkg, regardless of platform. Remove the per-platform symlink check that incorrectly expected individual files for iOS and tvOS.

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rolfbjarne commented Feb 19, 2026

View reviewed changes

msbuild/Xamarin.Shared/Xamarin.Shared.props Show resolved Hide resolved

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tests/msbuild/Xamarin.MacDev.Tasks.Tests/TaskTests/MergeableLibraryTests.cs Outdated Show resolved Hide resolved

[review] Address PR review comments

1a5150c

- Document StripMergeableLibraries property in build-properties.md - Remove [Category ("Multiplatform")] from BindingMergeableFrameworksProject test - Replace custom RunProcess with ExecutionHelper in MergeableLibraryTests

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vs-mobiletools-engineering-service2 commented Feb 19, 2026

✅ [CI Build #1a5150c] Build passed (Build packages) ✅

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vs-mobiletools-engineering-service2 commented Feb 19, 2026

✅ [PR Build #1a5150c] Build passed (Detect API changes) ✅

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vs-mobiletools-engineering-service2 commented Feb 19, 2026

✅ API diff for current PR / commit

✅ API diff vs stable

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vs-mobiletools-engineering-service2 commented Feb 19, 2026

✅ [CI Build #1a5150c] Build passed (Build macOS tests) ✅

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vs-mobiletools-engineering-service2 commented Feb 19, 2026

💻 [CI Build #1a5150c] Tests on macOS X64 - Mac Sonoma (14) passed 💻

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vs-mobiletools-engineering-service2 commented Feb 19, 2026

💻 [CI Build #1a5150c] Tests on macOS M1 - Mac Monterey (12) passed 💻

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vs-mobiletools-engineering-service2 commented Feb 19, 2026

💻 [CI Build #1a5150c] Tests on macOS M1 - Mac Ventura (13) passed 💻

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vs-mobiletools-engineering-service2 commented Feb 19, 2026

💻 [CI Build #1a5150c] Tests on macOS arm64 - Mac Tahoe (26) passed 💻

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vs-mobiletools-engineering-service2 commented Feb 19, 2026

💻 [CI Build #1a5150c] Tests on macOS arm64 - Mac Sequoia (15) passed 💻

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vs-mobiletools-engineering-service2 commented Feb 19, 2026

🔥 [CI Build #1a5150c] Test results 🔥

Test results

Failures

❌ linker tests

Failed tests

Successes