[dotnet] Fix loading oldest reference assemblies for library projects. Fixes #24043. #24181

rolfbjarne · 2025-11-05T10:30:01Z

Since this may result in unintuitive behavior (library projects are built differently than executable projects, so code that works in an executable project may not compile when moved to a library project), an escape hatch was implemented as well.

One unintuitive behavior was when building an executable project with a library project from Windows: if the library project needs the remote connection, it would use a different workload, and different remote connection, than the executable project, which just wouldn't work. So we don't enable this new behavior when library projects need the remote connection (which is when bundle resources are precompiled for the library project; aka when BundleOriginalResources=false - note that it's enabled by default in .NET 10, so developers must opt in to run into this problem and thus not getting this new behavior).

Fixes #24043.

…Fixes #24043. Since this may result in unintuitive behavior (library projects are built differently than executable projects, so code that works in an executable project may not compile when moved to a library project), an escape hatch was implemented as well. Fixes #24043.

Copilot

Pull Request Overview

This PR introduces a default Target Platform Version (TPV) for library projects across all Apple platforms (iOS, tvOS, macOS, MacCatalyst). When building a class library without an explicit TPV, the system now defaults to the lowest supported TPV for the current .NET version. This allows libraries to be built without specifying a TPV while maintaining compatibility.

Key changes:

Modified build system to set default TPV for libraries via new Makefile variables
Updated workload manifest generator to recognize lowest TPV per .NET version and conditionally import it for libraries
Enhanced test infrastructure to validate the default TPV behavior
Consolidated MyClassLibrary test projects to use shared source files

Reviewed Changes

Copilot reviewed 14 out of 14 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
tests/dotnet/UnitTests/ProjectTest.cs	Added assertions to verify default TPV is correctly applied to library builds
tests/Makefile	Added export of `*_TARGET_PLATFORM_VERSION_LIBRARY` variables to test configurations
scripts/generate-workloadmanifest-targets/generate-workloadmanifest-targets.cs	Added logic to compute lowest TPV per .NET version and conditionally import for libraries
tests/dotnet/MyClassLibrary/shared.csproj	New shared project file for consolidating common source files
tests/dotnet/MyClassLibrary/*/MyClassLibrary.csproj	Updated to import shared project instead of duplicating code
tests/dotnet/MyClassLibrary/*/MyClass.cs	Removed platform-specific duplicates
tests/dotnet/MyClassLibrary/MyClass.cs	Now inherits from NSObject to ensure platform-specific behavior

scripts/generate-workloadmanifest-targets/generate-workloadmanifest-targets.cs

dalexsoto · 2025-11-06T16:37:18Z

@rolfbjarne backport all the things!

vs-mobiletools-engineering-service2 · 2025-11-06T19:27:09Z

✅ [CI Build #502b6aa] Build passed (Build packages) ✅

Pipeline on Agent
Hash: 502b6aab7c2e6bfb894688297b47cf811a5fbc1a [PR build]

vs-mobiletools-engineering-service2 · 2025-11-06T19:53:00Z

✅ [PR Build #502b6aa] Build passed (Detect API changes) ✅

Pipeline on Agent
Hash: 502b6aab7c2e6bfb894688297b47cf811a5fbc1a [PR build]

vs-mobiletools-engineering-service2 · 2025-11-06T20:04:25Z

✅ [CI Build #502b6aa] Build passed (Build macOS tests) ✅

Pipeline on Agent
Hash: 502b6aab7c2e6bfb894688297b47cf811a5fbc1a [PR build]

vs-mobiletools-engineering-service2 · 2025-11-06T20:12:37Z

💻 [CI Build #502b6aa] Tests on macOS X64 - Mac Sonoma (14) passed 💻

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

Pipeline on Agent
Hash: 502b6aab7c2e6bfb894688297b47cf811a5fbc1a [PR build]

vs-mobiletools-engineering-service2 · 2025-11-06T20:15:10Z

💻 [CI Build #502b6aa] Tests on macOS M1 - Mac Monterey (12) passed 💻

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

Pipeline on Agent
Hash: 502b6aab7c2e6bfb894688297b47cf811a5fbc1a [PR build]

vs-mobiletools-engineering-service2 · 2025-11-06T20:17:34Z

💻 [CI Build #502b6aa] Tests on macOS M1 - Mac Ventura (13) passed 💻

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

Pipeline on Agent
Hash: 502b6aab7c2e6bfb894688297b47cf811a5fbc1a [PR build]

vs-mobiletools-engineering-service2 · 2025-11-06T20:18:50Z

💻 [CI Build #502b6aa] Tests on macOS arm64 - Mac Tahoe (26) passed 💻

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

Pipeline on Agent
Hash: 502b6aab7c2e6bfb894688297b47cf811a5fbc1a [PR build]

vs-mobiletools-engineering-service2 · 2025-11-06T20:19:31Z

💻 [CI Build #502b6aa] Tests on macOS arm64 - Mac Sequoia (15) passed 💻

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

Pipeline on Agent
Hash: 502b6aab7c2e6bfb894688297b47cf811a5fbc1a [PR build]

vs-mobiletools-engineering-service2 · 2025-11-06T20:41:18Z

✅ API diff for current PR / commit

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 )

✅ 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 )

ℹ️ Generator diff

Generator Diff: vsdrops (html) vsdrops (raw diff) gist (raw diff) - Please review changes)

Pipeline on Agent
Hash: 502b6aab7c2e6bfb894688297b47cf811a5fbc1a [PR build]

vs-mobiletools-engineering-service2 · 2025-11-06T22:32:35Z

🚀 [CI Build #502b6aa] Test results 🚀

Test results

✅ All tests passed on VSTS: test results.

🎉 All 117 tests passed 🎉

Tests counts

✅ 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. [attempt 2] 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 4 tests passed. Html Report (VSDrops) Download
✅ linker: All 44 tests passed. Html Report (VSDrops) Download
✅ monotouch (iOS): All 8 tests passed. Html Report (VSDrops) Download
✅ monotouch (MacCatalyst): All 11 tests passed. Html Report (VSDrops) Download
✅ monotouch (macOS): All 9 tests passed. Html Report (VSDrops) Download
✅ monotouch (tvOS): All 10 tests passed. Html Report (VSDrops) Download
✅ msbuild: All 2 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

Pipeline on Agent
Hash: 502b6aab7c2e6bfb894688297b47cf811a5fbc1a [PR build]

…Fixes #24043. (#24181) Since this may result in unintuitive behavior (library projects are built differently than executable projects, so code that works in an executable project may not compile when moved to a library project), an escape hatch was implemented as well. One unintuitive behavior was when building an executable project with a library project from Windows: if the library project needs the remote connection, it would use a different workload, and different remote connection, than the executable project, which just wouldn't work. So we don't enable this new behavior when library projects need the remote connection (which is when bundle resources are precompiled for the library project; aka when `BundleOriginalResources=false` - note that it's enabled by default in .NET 10, so developers must opt in to run into this problem and thus not getting this new behavior). Fixes #24043. --------- Co-authored-by: GitHub Copilot <copilot@github.com> Co-authored-by: GitHub Actions Autoformatter <github-actions-autoformatter@xamarin.com>

rolfbjarne requested a review from Copilot November 5, 2025 10:30

rolfbjarne marked this pull request as draft November 5, 2025 10:30

rolfbjarne mentioned this pull request Nov 5, 2025

[release/9.0.1xx] [dotnet] Fix loading oldest reference assemblies for library projects. Fixes #24043. #24079

Closed

rolfbjarne added this to the xcode26.1 milestone Nov 5, 2025

Document UseFloatingTargetPlatformVersion property

cea3c13

Copilot AI reviewed Nov 5, 2025

View reviewed changes

scripts/generate-workloadmanifest-targets/generate-workloadmanifest-targets.cs Outdated Show resolved Hide resolved

scripts/generate-workloadmanifest-targets/generate-workloadmanifest-targets.cs Outdated Show resolved Hide resolved

Auto-format source code

0ac5110

This comment has been minimized.

Sign in to view

dalexsoto approved these changes Nov 6, 2025

View reviewed changes

This comment has been minimized.

Sign in to view

Don't load lowest if we're not bundling original resources.

502b6aa

This comment has been minimized.

Sign in to view

dalexsoto merged commit 60eda76 into main Nov 6, 2025
45 checks passed

dalexsoto mentioned this pull request Nov 6, 2025

[release/10.0.1xx] [dotnet] Fix loading oldest reference assemblies for library projects Fixes #24043. #24194

Merged

[dotnet] Fix loading oldest reference assemblies for library projects. Fixes #24043. #24181

[dotnet] Fix loading oldest reference assemblies for library projects. Fixes #24043. #24181

Uh oh!

Conversation

rolfbjarne commented Nov 5, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

Copilot AI left a comment

Choose a reason for hiding this comment

Pull Request Overview

Reviewed Changes

Uh oh!

Uh oh!

Uh oh!

This comment has been minimized.

This comment has been minimized.

This comment has been minimized.

This comment has been minimized.

This comment has been minimized.

This comment has been minimized.

This comment has been minimized.

This comment has been minimized.

This comment has been minimized.

This comment has been minimized.

This comment has been minimized.

This comment has been minimized.

This comment has been minimized.

This comment has been minimized.

This comment has been minimized.

This comment has been minimized.

This comment has been minimized.

This comment has been minimized.

This comment has been minimized.

This comment has been minimized.

This comment has been minimized.

This comment has been minimized.

This comment has been minimized.

dalexsoto commented Nov 6, 2025

Uh oh!

This comment has been minimized.

This comment has been minimized.

This comment has been minimized.

This comment has been minimized.

This comment has been minimized.

This comment has been minimized.

This comment has been minimized.

This comment has been minimized.

This comment has been minimized.

This comment has been minimized.

This comment has been minimized.

vs-mobiletools-engineering-service2 commented Nov 6, 2025

✅ [CI Build #502b6aa] Build passed (Build packages) ✅

Uh oh!

vs-mobiletools-engineering-service2 commented Nov 6, 2025

✅ [PR Build #502b6aa] Build passed (Detect API changes) ✅

Uh oh!

vs-mobiletools-engineering-service2 commented Nov 6, 2025

✅ [CI Build #502b6aa] Build passed (Build macOS tests) ✅

Uh oh!

This comment has been minimized.

vs-mobiletools-engineering-service2 commented Nov 6, 2025

💻 [CI Build #502b6aa] Tests on macOS X64 - Mac Sonoma (14) passed 💻

Uh oh!

vs-mobiletools-engineering-service2 commented Nov 6, 2025

💻 [CI Build #502b6aa] Tests on macOS M1 - Mac Monterey (12) passed 💻

Uh oh!

vs-mobiletools-engineering-service2 commented Nov 6, 2025

💻 [CI Build #502b6aa] Tests on macOS M1 - Mac Ventura (13) passed 💻

Uh oh!

vs-mobiletools-engineering-service2 commented Nov 6, 2025

💻 [CI Build #502b6aa] Tests on macOS arm64 - Mac Tahoe (26) passed 💻

Uh oh!

vs-mobiletools-engineering-service2 commented Nov 6, 2025

💻 [CI Build #502b6aa] Tests on macOS arm64 - Mac Sequoia (15) passed 💻

Uh oh!

vs-mobiletools-engineering-service2 commented Nov 6, 2025

✅ API diff for current PR / commit

✅ API diff vs stable

ℹ️ Generator diff

Uh oh!

rolfbjarne commented Nov 5, 2025 •

edited

Loading