[Xamarin.Android.Build.Tasks] Remove dead InstantRun leftovers - #11656
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jonathanpeppers merged 2 commits intoJun 16, 2026
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Context: dotnet#9292 Context: dotnet#9297 When "Enhanced Fast Deployment" / Instant Run was removed in dotnet#9292 (MSBuild plumbing) and dotnet#9297 (native runtime), the corresponding Java support and the manifest-side hook were left behind. This commit finishes the cleanup that dotnet#9292 said was for "a future PR": * Delete `src-ThirdParty/bazel/java/mono/android/{debug,release}/MultiDexLoader.java` and `incrementaldeployment/IncrementalClassLoader.java`. These were introduced in dotnet#609 to spice fast-deployed `.dex` files into the app classloader at startup. With the native side gone, the release variant's `getDexList()` always returned an empty list (so `IncrementalClassLoader.inject()` was never called) and the debug variant scanned an `__override__/dexes/` directory that nothing in the build pipeline ever populates. * Delete `src/java-runtime/java/mono/android/incrementaldeployment/Placeholder.java`, the corresponding "tiny main dex" Bazel-style placeholder. * Drop the `<src-ThirdParty/bazel/...>` glob and the now-stale `RemoveItems` entries from `src/java-runtime/java-runtime.{csproj,targets}`. * Drop `ManifestDocument.MultiDex` and the `mono.android.MultiDexLoader` ContentProvider injection in `MergeManifest()`. Nothing else referenced the class name, and no test asserted the provider's presence. * Drop the corresponding `MultiDex` parameter from `GenerateMainAndroidManifest` and its callsite in `Microsoft.Android.Sdk.TypeMap.LlvmIr.targets`. * Remove the `bazelbuild/bazel` entry from `THIRD-PARTY-NOTICES.TXT` and the `update-tpn` skill, since the only vendored Bazel sources have been deleted. The `$(AndroidEnableMultiDex)` feature itself is unaffected. It still works via `android.support.multidex.MultiDexApplication` and D8/R8 producing `classes.dex` + `classes2.dex`; existing tests (`BuildMultiDexApplication`, `BuildAfterMultiDexIsNotRequired`, `MultiDexAndCodeShrinker`, etc.) cover that path and don't depend on the removed types. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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Pull request overview
Removes the remaining unreachable “Enhanced Fast Deployment” / Instant Run Java + manifest plumbing from the build tasks and Java runtime packaging, following the prior removal of the MSBuild and native runtime support. This simplifies the codebase and eliminates stale third-party Bazel remnants.
Changes:
- Removed the
mono.android.MultiDexLoaderContentProvider injection (and the associatedMultiDextask/manifest plumbing) which was only tied to dead Instant Run behavior. - Deleted the Bazel-derived Java sources (
MultiDexLoader,IncrementalClassLoader) and the matching runtime placeholder type, and stopped includingsrc-ThirdParty/bazelsources injava-runtime. - Updated third-party notices and the
update-tpnskill documentation to reflect the removal of vendored Bazel sources.
Reviewed changes
Copilot reviewed 11 out of 11 changed files in this pull request and generated no comments.
Show a summary per file
| File | Description |
|---|---|
| THIRD-PARTY-NOTICES.TXT | Removes the Bazel entry and its license block since Bazel sources are no longer vendored. |
| src/Xamarin.Android.Build.Tasks/Utilities/ManifestDocument.cs | Drops MultiDex property and removes provider injection of mono.android.MultiDexLoader. |
| src/Xamarin.Android.Build.Tasks/Tasks/GenerateMainAndroidManifest.cs | Removes the MultiDex MSBuild task parameter and stops passing it into manifest merging. |
| src/Xamarin.Android.Build.Tasks/Microsoft.Android.Sdk/targets/Microsoft.Android.Sdk.TypeMap.LlvmIr.targets | Stops passing MultiDex="$(AndroidEnableMultiDex)" to GenerateMainAndroidManifest. |
| src/java-runtime/java/mono/android/incrementaldeployment/Placeholder.java | Deletes unused Instant Run placeholder Java type. |
| src/java-runtime/java-runtime.targets | Removes now-stale RemoveItems entries that referenced deleted Bazel Java sources. |
| src/java-runtime/java-runtime.csproj | Stops glob-including src-ThirdParty/bazel/java/**/*.java into the Java runtime build inputs. |
| src-ThirdParty/bazel/java/mono/android/release/MultiDexLoader.java | Deletes unused Bazel-derived MultiDexLoader implementation. |
| src-ThirdParty/bazel/java/mono/android/incrementaldeployment/IncrementalClassLoader.java | Deletes unused Bazel-derived incremental classloader. |
| src-ThirdParty/bazel/java/mono/android/debug/MultiDexLoader.java | Deletes unused Bazel-derived debug MultiDexLoader implementation. |
| .github/skills/update-tpn/SKILL.md | Removes the Bazel row from the “vendored source” table since src-ThirdParty/bazel is gone. |
The BuildReleaseArm64 apkdiff regression tests fail because removing the mono.android.incrementaldeployment Java sources shrinks classes.dex by more than the 5% threshold: - BuildReleaseArm64(False,MonoVM) classes.dex 22384 -> 19036 - BuildReleaseArm64(False,NativeAOT) classes.dex 25400 -> 22016 - BuildReleaseArm64(True,CoreCLR) classes2.dex 156448 -> 108080 Refresh the reference .apkdesc files using the descriptions saved by apkdiff during the failing CI runs. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
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"Enhanced Fast Deployment" / Instant Run support was removed in #9292 (MSBuild plumbing) and #9297 (native runtime side). #9292''s description left a TODO: "In a future PR, we could consider making runtime changes to remove
instant_run_enabledas well." This is that future PR — it deletes the corresponding Java types and theAndroidManifest.xmlhook that instantiated them.What was actually still doing anything?
Nothing useful. After #9297 deleted the native side, the Bazel-derived Java types in
src-ThirdParty/bazel/java/mono/android/...became unreachable runtime no-ops:release/MultiDexLoader.java''sgetDexList()always returned an emptyList<String>, soIncrementalClassLoader.inject()was never called.debug/MultiDexLoader.javascanned$filesDir/.__override__/dexes/for hot-pushed.dexfiles. Nothing in the build pipeline ever populates that directory anymore —FastDeploy.csand the native runtime use.__override__/for managed.dlls and.__override__/$abi/for.sos, never.dex.incrementaldeployment/IncrementalClassLoader.javawas only reachable through the deadinject()call above.src/java-runtime/java/mono/android/incrementaldeployment/Placeholder.javawas the matching "tiny main dex" Bazel-style placeholder.The only consumer of the Java side was
ManifestDocument.MergeManifest(), which injected amono.android.MultiDexLoaderContentProviderwhen$(AndroidEnableMultiDex)was true. No test asserted the provider''s presence, and itsattachInfo()body was effectively a no-op.What this PR does
src-ThirdParty/bazel/java/...files andPlaceholder.java.bazelbuild/bazelentry fromTHIRD-PARTY-NOTICES.TXTand theupdate-tpnskill, since no vendored Bazel sources remain.<src-ThirdParty\bazel\...>glob and now-staleRemoveItemsentries fromsrc/java-runtime/java-runtime.{csproj,targets}.ManifestDocument.MultiDex, themono.android.MultiDexLoaderprovider injection, and the correspondingMultiDextask parameter onGenerateMainAndroidManifest(plus its callsite inMicrosoft.Android.Sdk.TypeMap.LlvmIr.targets).What is unaffected
$(AndroidEnableMultiDex)itself. The real multidex feature still works viaandroid.support.multidex.MultiDexApplicationand D8/R8 producingclasses.dex+classes2.dex. Existing testsBuildMultiDexApplication,BuildAfterMultiDexIsNotRequired,CustomApplicationClassAndMultiDex, andMultiDexAndCodeShrinkercover that path and don''t reference any of the removed types.$(_InstantRunEnabled)checks #9292 and Remove native runtime support for instant run #9297.BuildTest2MultiDex tests cover the supported path; no new tests are needed for code that nothing reaches.