Remove the obsolete AndroidClientHandler class

[simonrozsival]

This PR removes the obsolete AndroidClientHandler class and leaves just the AndroidMessageHandler class as the native http handler. The $(AndroidHttpClientHandlerType) property and the XA_HTTP_CLIENT_HANDLER_TYPE environment variable are now ignored.

[Copilot]

Pull request overview

Removes the deprecated Xamarin.Android.Net.AndroidClientHandler class so only AndroidMessageHandler remains as the native HTTP handler. The $(AndroidHttpClientHandlerType) MSBuild property and the XA_HTTP_CLIENT_HANDLER_TYPE environment variable are now ignored (with the property producing a build error if set), and the related MSBuild plumbing, error codes (XA1031/XA1032/XA1033), runtime selection logic, docs, and tests are deleted. A small unrelated tweak in AndroidMessageHandler.HandleRedirect short-circuits cross-scheme redirects to let the client decide.

Changes:

• Delete AndroidClientHandler (and its .Legacy.cs), update public API baselines on API-35/36/36.1/37, and add API-compat acceptable-breakages entries.
• Remove CheckClientHandlerType task, XA1031/1032/1033 resources/docs, HttpClientHandlerType task properties, XA_HTTP_CLIENT_HANDLER_TYPE env injection, AndroidEnvironment.GetHttpMessageHandler selection logic, and related tests.
• Refactor _CheckAndroidHttpClientHandlerType target to emit an MSBuild <Error/> when the property is set; add cross-scheme redirect handling in AndroidMessageHandler; split HttpClientIntegrationTests into a single AndroidMessageHandlerIntegrationTests fixture.

Reviewed changes

Copilot reviewed 44 out of 46 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
src/Mono.Android/Xamarin.Android.Net/AndroidClientHandler.cs, AndroidClientHandler.Legacy.cs	Delete the deprecated wrapper and its legacy implementation
src/Mono.Android/Xamarin.Android.Net/AndroidMessageHandler.cs	Drop unused *Internal shims; add cross-scheme redirect short-circuit
src/Mono.Android/Android.Runtime/AndroidEnvironment.cs	Replace XA_HTTP_CLIENT_HANDLER_TYPE-based selection with a hard-coded new AndroidMessageHandler()
src/Mono.Android/Mono.Android.csproj	Drop AndroidClientHandler.cs from compilation
src/Mono.Android/PublicAPI/API-3{5,6,6.1,7}/PublicAPI.{Shipped,Unshipped}.txt	Move AndroidClientHandler API surface to REMOVED
src/Microsoft.Android.Sdk.ILLink/MarkJavaObjects.cs	Remove custom HTTP handler preservation logic
src/Xamarin.Android.Build.Tasks/Xamarin.Android.Common.targets	Drop CheckClientHandlerType UsingTask; replace check target body with an <Error/>; stop forwarding HttpClientHandlerType
src/Xamarin.Android.Build.Tasks/Microsoft.Android.Sdk/targets/*.targets	Drop HttpClientHandlerType parameter wiring and the default AndroidHttpClientHandlerType / UseNativeHttpHandler derivation
src/Xamarin.Android.Build.Tasks/Tasks/CheckClientHandlerType.cs	Remove obsolete task
src/Xamarin.Android.Build.Tasks/Tasks/Generate*Sources.cs	Drop HttpClientHandlerType task property and threading through AddDefaultEnvironmentVariables
src/Xamarin.Android.Build.Tasks/Utilities/Environment{Builder,FilesParser}.cs	Remove AddHttpClientHandlerType/HaveHttpMessageHandler plumbing
src/Xamarin.Android.Build.Tasks/Properties/Resources.Designer.cs	Remove XA1031/XA1031_HCH/XA1032/XA1033 accessors
src/Xamarin.Android.Build.Tasks/Tests/.../CheckClientHandlerTypeTests.cs, LinkerTests.cs, EnvironmentContentTests.cs	Delete tests that exercised the removed plumbing
src/profiled-aot/dotnet.aotprofile.txt	Drop IsAcceptableHttpMessageHandlerType entry
tests/api-compatibility/acceptable-breakages-vReference-net11.0.txt	Empty out the compat exception list (now reset to just the header)
tests/Mono.Android-Tests/.../{HttpClientIntegrationTests.cs,AndroidClientHandlerTests.cs,Android.Runtime/AndroidEnvironmentTest.cs}	Remove handler-agnostic integration tests and AndroidEnvironment unit test
tests/Mono.Android-Tests/.../AndroidMessageHandlerIntegrationTests.cs	New consolidated integration test fixture targeting only AndroidMessageHandler
tests/Mono.Android-Tests/Mono.Android-Tests/Mono.Android.NET-Tests.csproj	Update compile list and remove AndroidClientHandler category from exclusions
tests/Mono.Android-Tests/Mono.Android-Tests/TrimmerRoots.xml	Stop preserving AndroidClientHandler
Documentation/docs-mobile/{messages/{xa1031,xa1032,xa1033}.md,index.md,TOC.yml,building-apps/build-properties.md}	Remove docs for retired error codes and the AndroidHttpClientHandlerType property
.github/skills/tests/references/test-catalog.md	Drop references to AndroidClientHandler test/category

Files not reviewed (1)

• src/Xamarin.Android.Build.Tasks/Properties/Resources.Designer.cs: Language not supported

[jonathanpeppers]

/review

[github-actions]

✅ Android PR Reviewer completed successfully!

[github-actions]

⚠️ Needs Changes

Clean PR that successfully removes the obsolete AndroidClientHandler class, simplifies GetHttpMessageHandler() to directly instantiate AndroidMessageHandler, and properly redirects users to $(UseNativeHttpHandler). The redirect behavior change for cross-scheme redirects is a nice alignment with SocketsHttpHandler. Public API tracking and API compatibility breakage files look correct.

However, the removal is incomplete — several references to the removed functionality were left behind:

Issues by severity

Severity	Count
❌ Error	1
⚠️ Warning	2
💡 Suggestion	3

Key issues

1. ❌ Build break: EnvironmentFilesParserTests.DetectsHttpMessageHandler still references the removed HaveHttpMessageHandler property — this will fail to compile.

2. ⚠️ Orphaned code: GenerateNativeApplicationConfigSources.HttpClientHandlerType property and EnvironmentBuilder.defaultHttpMessageHandler field are unused after this PR (the latter will trigger TreatWarningsAsErrors).

3. ⚠️ Orphaned resource entries: XA1031, XA1031_HCH, XA1032, XA1033 were removed from Resources.Designer.cs but still exist in Resources.resx.

Positive callouts

• The GetHttpMessageHandler() simplification is a great improvement — direct instantiation eliminates reflection, DynamicDependency, Type.GetType, and the XA_HTTP_CLIENT_HANDLER_TYPE env var indirection.
• Good use of <Error> in targets to give users a clear migration path.
• The redirect scheme change is well-isolated and the disposeRet = false pattern correctly delegates to the caller.

Generated by Android PR Reviewer for issue #11393 · ● 29.6M

[simonrozsival]

@copilot address review

[Copilot]

@copilot address review

Addressed the outstanding review items in afecf6a: removed stale HaveHttpMessageHandler test usage, removed orphaned HttpClientHandlerType/defaultHttpMessageHandler, and removed obsolete XA1031/XA1032/XA1033 entries from Resources.resx.

[simonrozsival]

@copilot fix build:

 (CoreCompile target) -> /Users/runner/work/1/s/tests/Mono.Android-Tests/Mono.Android-Tests/Xamarin.Android.Net/AndroidMessageHandlerTests.cs(19,44): error CS0246: The type or namespace name 'AndroidHandlerTestBase' could not be found (are you missing a using directive or an assembly reference?) [/Users/runner/work/1/s/tests/Mono.Android-Tests/Mono.Android-Tests/Mono.Android.NET-Tests.csproj]
141 Warning(s)
1 Error(s)
```

[Copilot]

@copilot fix build:

 (CoreCompile target) -> 

...

Fixed in 21c1cbd (with follow-up cleanup in f5e7f1f). I restored Xamarin.Android.Net/AndroidHandlerTestBase.cs and added it back to Mono.Android.NET-Tests.csproj, so AndroidMessageHandlerTests : AndroidHandlerTestBase now compiles again. No UI changes in this fix.

Addressed all Android PR Reviewer comments in follow-up commits.

[simonrozsival]

/review

[github-actions]

✅ Android PR Reviewer completed successfully!

[github-actions]

Review Summary — ⚠️ Needs attention

Overall: Clean, thorough removal of the obsolete AndroidClientHandler class and its supporting infrastructure. The code deletion is consistent — all references to AndroidClientHandler, XA_HTTP_CLIENT_HANDLER_TYPE, HttpClientHandlerType, CheckClientHandlerType, and error codes XA1031–XA1033 are properly cleaned up. API compatibility breakages are documented, PublicAPI files are updated, and the migration error message in _CheckAndroidHttpClientHandlerType provides clear guidance.

Positive callouts

• GetHttpMessageHandler simplification — The old reflection-based handler resolution with trimming annotations ([DynamicDependency], [UnconditionalSuppressMessage]) is replaced with a direct new AndroidMessageHandler(). Much safer and simpler.
• Pre-existing bugs removed — The deleted ConfigureKeyManagerFactoryInternal and ConfigureCustomSSLSocketFactoryInternal methods were infinitely recursive (calling themselves instead of the non-Internal variants). Good riddance.
• Test restructuring — Renaming AndroidClientHandlerTests.cs → AndroidHandlerTestBase.cs and consolidating HttpClientIntegrationTests.cs into AndroidMessageHandlerIntegrationTests.cs properly eliminates the dual-handler test hierarchy.

Issues by severity

Severity	Count	Summary
⚠️ Warning	1	Redirect scheme-change logic is a separate behavior change that blocks HTTP→HTTPS redirects
💡 Suggestion	2	Coded error for migration target, docs expansion

CI Status

Public CI checks (license/cla, dotnet-android) are ✅ passing.

Generated by Android PR Reviewer for issue #11393 · ● 17.9M