Enable trim/AOT analyzers for Microsoft.Build and clean up annotations by JeremyKuhne · Pull Request #14064 · dotnet/msbuild

JeremyKuhne · 2026-06-13T00:11:09Z

Summary

Makes the Microsoft.Build evaluation object model trim- and Native-AOT-capable so an AOT-compiled host (the dotnet CLI) can evaluate and build projects in-process, and fail observably wherever a path genuinely requires run-time reflection (loading a task, SDK resolver, logger, or build check discovered by name) so the host can fall back to a JIT MSBuild - never a silent no-op and never a crash deep in the engine.

The work is evaluation-first: evaluation is kept fully trim/AOT-clean today, and execution becomes possible through closed-world host registration (registered SDK resolvers and task classes) while open-world reflective paths fail observably. The build is clean on both net10.0 and net472 (0 IL warnings, 0 warnings, 0 errors).

Change breakdown

About half the diff is documentation; validation and engine code are each roughly a quarter. The engine change is intentionally small and surgical - overwhelmingly trim/AOT annotations and feature-switch gating rather than behavior changes to the JIT path.

Category	Files	Added	Deleted
Documentation	15	4,653	0
Validation (AOT harness + unit tests)	22	2,158	21
Engine code	69	1,990	355
Localization (`.xlf`/`.resx` for 4 new diagnostics)	14	344	0
Other (`.gitignore`)	1	3	0
Total	121	9,148	376

The actual engine code change is ~2,000 lines across 69 files; the remaining ~7,000 lines are documentation, the validation harness/tests, and auto-generated localization.

New public API surface

Three reflection-free, closed-world registration entry points let a host hand MSBuild the types it needs up front so the trimmer preserves them:

Microsoft.Build.Framework.SdkResolver.Register(SdkResolver) - contribute a pre-constructed SDK resolver instead of MSBuild discovering and Assembly.LoadFrom-ing one by reflection.
Microsoft.Build.Utilities.Task.RegisterTask<T>() (plus a RegisterTask(string, Func<ITask>) overload) - register a task class so the engine constructs, binds, and runs it with reflective task execution disabled.
Microsoft.Build.Utilities.TaskItem.RegisterTaskParameterValueType<T>() and RegisterTaskParameterItemType<T>() - resolve <UsingTask> / <ParameterGroup> parameter types without a by-name Type.GetType.

Four new diagnostics report unsupported reflective paths under trimming/AOT:

MSB4282 - an SDK requires a dynamically-loaded SDK resolver (unsupported in a trimmed/AOT host).
MSB4283 - a task requires reflective loading/execution (unsupported in a trimmed/AOT host).
MSB4284 - a custom BuildCheck requires reflective plugin loading (unsupported in a trimmed/AOT host).
MSB4285 - a logger named by its assembly/class requires reflective loading (unsupported in a trimmed/AOT host).

API-review callout: besides the additive registration APIs above, there is a deliberate public trim-metadata change - the public ITaskFactory / ITaskFactory2 / ITaskFactory3 Initialize and CreateTask members now carry [RequiresUnreferencedCode], and ITaskFactory.TaskType carries [DynamicallyAccessedMembers(PublicProperties)]. There is no managed signature change, but a host reaching task creation through the interface now sees an honest IL2026, and a third-party ITaskFactory that enables trim analysis gets IL2046 until it adds the matching attribute.

AOT validation

A new Native AOT validation harness (src/aot-validation/) publishes a fully AOT-compiled image and runs it end-to-end. It validates that AOT works for both evaluating and building the basic library (dotnet new classlib) and executable (dotnet new console) project templates:

Evaluate - DotnetNew_Classlib_EvaluatesAsLibraryProject, DotnetNew_Console_EvaluatesAsExecutableProject: evaluate the stock templates through the object model under AOT.
Build - DotnetNew_Classlib_BuildUnderAot_RunsRegisteredTasksThenFailsObservably, DotnetNew_Console_BuildUnderAot_RunsRegisteredTasksThenFailsObservably: build the templates in-process under AOT, confirming registered/intrinsic tasks run and that an unsupported reflective task fails observably (MSB4283) rather than crashing.

Additional harness coverage exercised against the published AOT image: object-model evaluation, property-function reachability, and each of the three registration APIs (SDK resolver, task class, task-parameter type).

Design criterion: fail observably, never silently

A trimmed/AOT path that cannot run surfaces a reported error (or a host-readable property) so the host can branch and fall back; it never silently drops a project's expressed intent and never crashes in the engine. [UnconditionalSuppressMessage] is used only for provable false positives; accurate warnings are gated behind feature switches (with observable failure) or carry honest [RequiresUnreferencedCode] to a public boundary.

Design notes, the strategy catalog, and living suppression/annotation trackers are in documentation/aot/; the host-registration API proposals are in documentation/specs/.

Copilot

Pull request overview

This PR enables IL trim/AOT analysis for Microsoft.Build (via IsAotCompatible on net8.0+) and resolves the resulting IL warnings primarily by propagating [RequiresUnreferencedCode] through reflection-heavy/extensibility call chains, adding targeted suppressions at message-pump/delegate boundaries, and tightening DynamicallyAccessedMembers annotations.

Changes:

Enable trim/AOT analyzers for src/Build/Microsoft.Build.csproj (net8.0+ only) and eliminate IL warnings across net10.0 + net472.
Propagate [RequiresUnreferencedCode] across task loading, SDK resolution, logging, project cache, evaluation/graph, build-request engine, and BuildCheck acquisition.
Apply a small set of AOT-friendly refactors (notably ParallelWorkSet, task-parameter array creation, and logger registration) to avoid analyzer-triggering patterns.

Reviewed changes

Copilot reviewed 64 out of 64 changed files in this pull request and generated 5 comments.

Show a summary per file

File	Description
src/Build/Microsoft.Build.csproj	Enables `IsAotCompatible` for net8.0+ to run trim/AOT analyzers.
src/Tasks/XamlTaskFactory/XamlTaskFactory.cs	Adds `DynamicallyAccessedMembers` annotation to `TaskType`.
src/Tasks/RoslynCodeTaskFactory/RoslynCodeTaskFactory.cs	Isolates trim-unsafe reflection behind RUC helpers; adjusts suppressions.
src/Tasks/CodeTaskFactory.cs	Annotates `TaskType` with `DynamicallyAccessedMembers`; updates stub branch.
src/Shared/TypeLoader.cs	Marks runtime assembly/type loading paths as RUC.
src/Shared/TaskParameter.cs	AOT-friendly array creation for primitive arrays during translation.
src/Shared/TaskLoader.cs	Adds suppression on type-filter delegate used during reflective discovery.
src/Shared/TaskEngineAssemblyResolver.cs	Adds suppression on assembly-resolve handlers.
src/Framework/ReflectableTaskPropertyInfo.cs	Reworks property lookup to avoid trim-unfriendly APIs; narrows DAM.
src/Framework/Loader/LoadedType.cs	Expands DAM requirements to include public parameterless ctor.
src/Framework/ITaskFactory.cs	Adds DAM annotation to `ITaskFactory.TaskType`.
src/Build/Utilities/NuGetFrameworkWrapper.cs	Marks runtime load/reflection over NuGet.Frameworks as RUC.
src/Build/ObjectModelRemoting/DefinitionObjectsLinks/ProjectLink.cs	Marks remote evaluation/build helper APIs as RUC.
src/Build/Logging/LoggerDescription.cs	Marks reflective logger creation as RUC; adds delegate suppressions.
src/Build/Instance/TaskRegistry.cs	Marks reflective task factory loading/parameter reflection as RUC; adds suppressions for unrecognized reflection patterns.
src/Build/Instance/TaskFactories/AssemblyTaskFactory.cs	Marks assembly task factory type-loading paths as RUC; annotates `TaskType`.
src/Build/Instance/ProjectInstance.cs	Marks project instance constructors/build/evaluation-heavy entrypoints as RUC.
src/Build/Graph/ProjectGraph.cs	Marks project graph construction/evaluation entrypoints as RUC.
src/Build/Graph/ParallelWorkSet.cs	Replaces `Lazy<TResult>` with custom lazy work item to avoid IL2091.
src/Build/Graph/GraphBuildSubmission.cs	Marks cache-plugin initialization paths as RUC.
src/Build/Evaluation/IntrinsicFunctions.cs	Suppresses trim warning around Lazy factory calling RUC code.
src/Build/Evaluation/Expander.cs	Adds DAM annotations and suppressions around property-function reflection paths.
src/Build/Evaluation/Evaluator.cs	Marks evaluation/import expansion paths as RUC.
src/Build/Definition/ProjectCollection.cs	Adds RUC propagation and boundary suppressions around logger registration and project loading.
src/Build/Definition/Project.cs	Marks public project construction/evaluation/build entrypoints as RUC.
src/Build/Construction/Solution/SolutionProjectGenerator.cs	Marks solution evaluation/generation paths as RUC.
src/Build/BuildCheck/Infrastructure/NullBuildCheckManager.cs	Marks custom BuildCheck acquisition as RUC.
src/Build/BuildCheck/Infrastructure/IBuildCheckManager.cs	Adds RUC to custom BuildCheck acquisition contract.
src/Build/BuildCheck/Infrastructure/BuildCheckManagerProvider.cs	Marks custom check materialization/acquisition paths as RUC; adds suppression boundary.
src/Build/BuildCheck/Infrastructure/BuildCheckBuildEventHandler.cs	Adds suppression boundary on build-event handler invoking acquisition.
src/Build/BuildCheck/Acquisition/IBuildCheckAcquisitionModule.cs	Marks acquisition interface as RUC.
src/Build/BuildCheck/Acquisition/BuildCheckAcquisitionModule.cs	Marks acquisition implementation as RUC.
src/Build/BackEnd/TaskExecutionHost/TaskExecutionHost.cs	Adds RUC propagation and AOT-friendly array creation for task parameters.
src/Build/BackEnd/Shared/BuildRequestConfiguration.cs	Marks project load/eval into configuration as RUC.
src/Build/BackEnd/Node/OutOfProcNode.cs	Adds message-pump suppression boundary; propagates RUC into request handling.
src/Build/BackEnd/Node/InProcNode.cs	Adds message-pump suppression boundary; propagates RUC into request handling.
src/Build/BackEnd/Components/SdkResolution/SdkResolverService.cs	Marks SDK resolution (runtime resolver load/reflection) as RUC.
src/Build/BackEnd/Components/SdkResolution/SdkResolverLoader.cs	Marks SDK resolver discovery/loading/reflection as RUC.
src/Build/BackEnd/Components/SdkResolution/OutOfProcNodeSdkResolverService.cs	Propagates RUC to out-of-proc resolver service.
src/Build/BackEnd/Components/SdkResolution/MainNodeSdkResolverService.cs	Adds suppression boundary in packet handler; propagates RUC to ResolveSdk.
src/Build/BackEnd/Components/SdkResolution/ISdkResolverService.cs	Adds RUC to SDK resolver service contract.
src/Build/BackEnd/Components/SdkResolution/HostedSdkResolverServiceBase.cs	Adds RUC to hosted resolver service base contract.
src/Build/BackEnd/Components/SdkResolution/CachingSdkResolverService.cs	Propagates RUC to caching wrapper.
src/Build/BackEnd/Components/SdkResolution/CachingSdkResolverLoader.cs	Propagates RUC to caching loader overrides.
src/Build/BackEnd/Components/RequestBuilder/TaskHost.cs	Adds suppression boundary for public task-callback contract; propagates RUC into internal build entrypoints.
src/Build/BackEnd/Components/RequestBuilder/TaskBuilder.cs	Propagates RUC to task execution pipeline methods.
src/Build/BackEnd/Components/RequestBuilder/TargetEntry.cs	Propagates RUC to target execution pipeline methods.
src/Build/BackEnd/Components/RequestBuilder/TargetBuilder.cs	Propagates RUC to target build/callback methods.
src/Build/BackEnd/Components/RequestBuilder/RequestBuilder.cs	Propagates RUC through request builder thread/pump paths.
src/Build/BackEnd/Components/RequestBuilder/ITaskBuilder.cs	Adds RUC to task-builder contract.
src/Build/BackEnd/Components/RequestBuilder/ITargetBuilderCallback.cs	Adds RUC to target-builder callback contract.
src/Build/BackEnd/Components/RequestBuilder/ITargetBuilder.cs	Adds RUC to target-builder contract.
src/Build/BackEnd/Components/RequestBuilder/IRequestBuilderCallback.cs	Adds RUC to request-builder callback contract.
src/Build/BackEnd/Components/RequestBuilder/IRequestBuilder.cs	Adds RUC to request-builder contract.
src/Build/BackEnd/Components/RequestBuilder/IntrinsicTasks/MSBuild.cs	Adds suppression boundary for intrinsic-task reflective execution wall.
src/Build/BackEnd/Components/RequestBuilder/IntrinsicTasks/IntrinsicTaskFactory.cs	Adds DAM annotations to intrinsic task factory `TaskType`.
src/Build/BackEnd/Components/ProjectCache/ProjectCacheService.cs	Marks plugin loading/reflection/materialization as RUC; adds DAM for ctor activation.
src/Build/BackEnd/Components/Logging/LoggingService.cs	Removes reflection for in-box forwarding logger; factors core registration helper; adds RUC to reflective entrypoints.
src/Build/BackEnd/Components/Logging/ILoggingService.cs	Adds RUC to distributed logger registration / node logger init contracts.
src/Build/BackEnd/Components/Logging/BuildErrorTelemetryTracker.cs	Replaces enum-values reflection with constant-length array sizing.
src/Build/BackEnd/Components/BuildRequestEngine/IBuildRequestEngine.cs	Adds RUC to engine contract entrypoints.
src/Build/BackEnd/Components/BuildRequestEngine/BuildRequestEngine.cs	Propagates RUC into engine implementation; adds suppression boundaries for event handlers.
src/Build/BackEnd/BuildManager/BuildSubmission.cs	Propagates RUC through submission execution entrypoints.
src/Build/BackEnd/BuildManager/BuildManager.cs	Propagates RUC through build lifecycle and packet processing entrypoints; adds message-pump suppression boundary.

github-actions

Design Before Implementation — ISSUE
SEVERITY: MAJOR
FILE: src/Build/BackEnd/Components/Logging/BuildErrorTelemetryTracker.cs
LINES: 39 (the _errorCounts initializer)
SCENARIO: A developer adds a new ErrorCategory value after Other — e.g., ErrorCategory.Security at ordinal 16. (int)ErrorCategory.Other + 1 remains 16 (array indices 0–15). TrackError calls Interlocked.Increment(ref _errorCounts[(int)ErrorCategory.Security]) which dereferences _errorCounts[16] → IndexOutOfRangeException at runtime. There is nothing in the code that enforces the "Other is always last" invariant, so this is a silent time bomb for the next contributor who extends the enum.
FINDING: The replacement of Enum.GetValues(typeof(ErrorCategory)).Length with (int)ErrorCategory.Other + 1 avoids the reflection/trimming warning but introduces a fragile positional assumption that is not machine-checkable. The original code was self-maintaining; the new code is not.
RECOMMENDATION: Use the trim-safe generic overload Enum.GetValues<ErrorCategory>().Length (available since .NET 5, annotated only with [RequiresDynamicCode], not [RequiresUnreferencedCode], so it does not trigger IL2026). Add a #if NET guard for the .NET Framework build path (Enum.GetValues(typeof(ErrorCategory)).Length). Alternatively, add a sentinel Count member at the end of the enum and use new int[(int)ErrorCategory.Count] — that is the classic pattern to make array sizing both AOT-safe and self-maintaining.

All other evaluated dimensions are clean:

WorkItem class (ParallelWorkSet.cs): The explicit comment correctly explains why Lazy<T> is unsuitable (its [DynamicallyAccessedMembers] annotation on T propagates to ParallelWorkSet<TKey, TResult> and produces IL2091). The documented single-writer / happens-before model makes the lock-free Value getter sound. LGTM.
RegisterDistributedLoggerCore extraction (LoggingService.cs): Both call sites hold _lockObject before entering Core, so all shared mutable state is properly guarded. The extraction cleanly separates the reflection-free fast path (RegisterLogger with a pre-instantiated CentralForwardingLogger) from the reflection path. LGTM.
ReflectableTaskPropertyInfo.cs manual loop: The change from GetProperty(..., BindingFlags.IgnoreCase) (which required NonPublicProperties in the DAM annotation) to an explicit loop over GetProperties(PublicProperties) with OrdinalIgnoreCase is the correct trim-safe replacement. Using LINQ FirstOrDefault would be semantically equivalent but would allocate an enumerator; the manual loop is preferred on a property-lookup hot path. LGTM.
Array.CreateInstanceFromArrayType (TaskParameter.cs, TaskExecutionHost.cs): Switching the switch arms to concrete array types (typeof(char[]) etc.) and using Array.CreateInstanceFromArrayType is exactly the right API for AOT-safe typed-array construction, with a correct #if NET fallback for .NET Framework. LGTM.

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Generated by Expert Code Review (on open) for issue #14064 · 5.7K AIC · ⌖ 12.4 AIC · ⊞ 30.1K ambient context

…14079) ## Summary Splits the **functional / method-body changes** out of the broader trim-enablement work (#14064) so they can be reviewed independently of the annotation churn. This PR contains **no** `[RequiresUnreferencedCode]`/`[DynamicallyAccessedMembers]` propagation cascade and does **not** flip on the trim/AOT analyzers — those remain in #14064. ### Property-function evaluation (made trim-compatible by construction) - `Function<T>._receiverType` (and the `Function` ctor `receiverType` parameter) are annotated with `[DynamicallyAccessedMembers(All)]` as a single chokepoint, with proof-based suppressions on the `InvokeMember`/`GetMethods`/`GetConstructor` sites. - The curated receiver-type allowlist (`AvailableStaticMethods`) is preserved with `[DynamicDependency]`, constrained to the members property functions actually use (public ctors/methods/properties/fields; non-public methods for `IntrinsicFunctions`). - The runtime assembly-probing path (`MSBUILDENABLEALLPROPERTYFUNCTIONS=1`) is gated behind the `EnableAllPropertyFunctions` trimmer feature switch so the trimmer removes it; the env var stays honored at run time. net472 polyfills added for `FeatureSwitchDefinition`/`DynamicDependency`. ### Functional changes making reflection AOT/trim-friendly (no behavior change) - **TaskParameter / TaskExecutionHost**: construct typed arrays via `Array.CreateInstanceFromArrayType` instead of `Array.CreateInstance(elementType)`. - **ParallelWorkSet**: a custom `WorkItem` replaces `Lazy<TResult>` (avoids the DAM requirement `Lazy<T>` places on `TResult`). - **BuildErrorTelemetryTracker**: size the count array from a `Count` sentinel instead of `Enum.GetValues(...)`. - **LoggingService**: instantiate the built-in `CentralForwardingLogger` directly instead of via reflection. - **ReflectableTaskPropertyInfo**: resolve the property via `GetProperties()` enumeration (also avoids `AmbiguousMatchException` on shadowed properties). ## Validation - `Microsoft.Build` compiles for **net10.0** (`-p:IsTrimmable=true`) and **net472**. - Targeted unit tests pass: `ParallelWorkSet`, `TaskExecutionHost_Tests`, `LoggingService_Tests`, `TaskParameter`.

Copilot

Pull request overview

Copilot reviewed 120 out of 121 changed files in this pull request and generated 1 comment.

Makes the MSBuild evaluation object model trim- and Native-AOT-capable so an AOT-compiled host (the dotnet CLI) can evaluate and build in-process, and fail observably where reflective loading is required so the host can fall back to a JIT MSBuild. Code: trim/AOT annotations, feature switches, and closed-world host-registration APIs (SdkResolver.Register, Task.RegisterTask, TaskItem task-parameter-type registration); new diagnostics MSB4282/MSB4283 for unsupported reflective paths. Validation: a Native AOT harness that publishes and runs an AOT image, evaluating and building the classlib (library) and console (executable) templates. Documentation: design/strategy notes, living suppression and annotation trackers, per-area deep dives, and the host-registration API specs.

Add ReadAllBytes/GetCreationTimeUtc/GetLastWriteTimeUtc to the read-only File property-function allowlist; the -mt tests for those methods now rely on the allowlist instead of the escape hatch. Route every EnableAllPropertyFunctions hatch test through the AppContext feature switch for deterministic, order-independent behavior, and keep a single env-var test that reflectively clears the switch (AppContext has no public unset state) to vet that MSBUILDENABLEALLPROPERTYFUNCTIONS still flows. Null-guard the BuildProject finally so a rejected overlapping build cannot NRE.

…ontext value When the .NET SDK hosts MSBuild in a trimmed / Native AOT process the BCL 'where am I' APIs point at the muxer / install root, not the versioned SDK directory that contains MSBuild. Following dotnet/sdk#55110, read the SDK-published 'Microsoft.DotNet.Sdk.Root' AppContext value (new DotNetSdkPaths helper) as an early step in BuildEnvironmentHelper resolution, before falling back to process/assembly discovery.

The rebase onto upstream/main integrated the typed TaskItem<T> / ITaskItem<T> task-parameter feature into Microsoft.Build, which this branch compiles with the trim/AOT analyzers enabled. Fix the merge-resolved using block (drop a duplicate System.Diagnostics and an unused System.Globalization) and guard CreateTaskItemOfT's MakeGenericType + expression Compile() behind RuntimeFeature.IsDynamicCodeSupported so it fails observably under trimming / Native AOT (clearing IL3050). Tracked as follow-up item 7.

JeremyKuhne · 2026-07-06T20:18:00Z

Windows Core failure — investigation

TL;DR: The Windows Core failure is an unrelated flaky Coordinator IPC test, not a regression from this PR. Recommend re-running the leg.

What failed

Build 1495736 reported Windows Core red with 1 error / 0 warnings.
The compile itself succeeded (0 Warning(s), 0 Error(s)). The single error is a process-level test failure: MSBuild.Coordinator.UnitTests.exe [net472|x86] crashed/hung (the Tests tab shows 0 clean test failures — the runner died rather than reporting an assertion).
Every other assembly passed, including Microsoft.Build.Engine.UnitTests on both net472 and net10.0.

Why it's unrelated to this PR

MSBuild.Coordinator / MSBuild.Coordinator.UnitTests is entirely upstream code — none of it is touched by this branch (git log main..HEAD -- src/MSBuild.Coordinator* is empty), and the suite references none of the files changed here (BuildEnvironmentHelper, DotNetSdkPaths, TaskExecutionHost, etc.).
This PR's changes are no-ops on net472 (the failing config): the new RuntimeFeature.IsDynamicCodeSupported / IL3050 guard is #if NET, and BuildEnvironmentHelper.TryFromSdkRoot reads AppContext.GetData("Microsoft.DotNet.Sdk.Root"), which is unset on net472 / SDK 10.0.300 and returns null.
Linux Core and macOS Core passed because the Coordinator component is net472-only and doesn't run there.

Why it's flaky

CoordinatorIntegration_Tests.ParallelBuilds_BothSucceedWithCoordinator spawns two parallel bootstrapped MSBuild processes over a named pipe with node-budget negotiation and 60s timeouts — inherently timing-sensitive under CI load.
The suite is recent (Add MSBuild Coordinator for fair-share node allocation #13653) and already has known Windows flakiness (see [Flaky Test] Quarantine 5 flaky tests (Windows-only) #14197, "[Flaky Test] Quarantine 5 flaky tests (Windows-only)").

Recommendation

Re-run the Windows Core leg — no code change is warranted for this PR. If the Coordinator suite keeps flaking it may warrant an additional quarantine entry, but that's separate from this change.

JeremyKuhne · 2026-07-06T20:25:32Z

@ViktorHofer I've updated for merge conflicts and the AppContext SDK root that the SDK pushes.

ViktorHofer · 2026-07-08T20:18:49Z

How should we maintain that list of BuildInTasks? I assume we don't want to register ALL msbuild inbox tasks? https://github.com/dotnet/msbuild/blob/main/src/Tasks/Microsoft.Common.tasks

ViktorHofer · 2026-07-08T20:22:14Z

/review

Updated [Microsoft.Build.Utilities.Core](https://github.com/dotnet/msbuild) from 18.9.6 to 18.10.1. <details> <summary>Release notes</summary> _Sourced from [Microsoft.Build.Utilities.Core's releases](https://github.com/dotnet/msbuild/releases)._ ## 18.10.1 ## What's Changed * [vs16.11] Update dependencies from dotnet/arcade by @dotnet-maestro[bot] in dotnet/msbuild#13103 * [vs17.12] Update dependencies from dotnet/arcade by @dotnet-maestro[bot] in dotnet/msbuild#13796 * [vs17.8] Update dependencies from dotnet/arcade by @dotnet-maestro[bot] in dotnet/msbuild#13902 * [vs17.11] Update dependencies from dotnet/arcade by @dotnet-maestro[bot] in dotnet/msbuild#13903 * [vs17.12] Update dependencies from dotnet/arcade by @dotnet-maestro[bot] in dotnet/msbuild#13909 * [vs17.12] Update dependencies from dotnet/arcade by @dotnet-maestro[bot] in dotnet/msbuild#13986 * Add vs18.9 to merge-flow config; retire vs18.3 by @JanProvaznik in dotnet/msbuild#14214 * Bump labeler-cache-retention to use issue-labeler v2.1.0 by @jeffhandley in dotnet/msbuild#14171 * Bump main to 18.10.0 after vs18.9 snap by @JanProvaznik in dotnet/msbuild#14216 * Improve release skill: Phase 2 DARC rules, VMR backflow, deterministic baseline by @JanProvaznik in dotnet/msbuild#14220 * Determinize release: hardcode OptProf baseline + Phase 3.2 baseline resolver by @JanProvaznik in dotnet/msbuild#14222 * Serialize BuildRequestConfiguration.RequestedTargets to fix solution metaproject MSB4057 in parallel builds by @ViktorHofer in dotnet/msbuild#14223 * [main] Update dependencies from nuget/nuget.client by @dotnet-maestro[bot] in dotnet/msbuild#14203 * Core support for AbsolutePath/FileInfo/DirectoryInfo and ITaskItem<T> as task parameters by @baronfel in dotnet/msbuild#13971 * [main] Update dependencies from dotnet/roslyn by @dotnet-maestro[bot] in dotnet/msbuild#14206 * Fix existence cache kind poisoning by @AlesProkop in dotnet/msbuild#14249 * [main] Source code updates from dotnet/dotnet by @dotnet-maestro[bot] in dotnet/msbuild#14226 * Don't disable the MSBuild server for /mt builds when node reuse is off by @AR-May in dotnet/msbuild#14248 * Enhance expert reviewer guidelines with additional checks. by @AR-May in dotnet/msbuild#14255 * [main] Source code updates from dotnet/dotnet by @dotnet-maestro[bot] in dotnet/msbuild#14253 * [main] Update dependencies from dotnet/roslyn by @dotnet-maestro[bot] in dotnet/msbuild#14268 * [main] Update dependencies from nuget/nuget.client by @dotnet-maestro[bot] in dotnet/msbuild#14267 * Bump github/gh-aw-actions/setup from 0.81.6 to 0.82.2 by @dependabot[bot] in dotnet/msbuild#14266 * Avoid boxing the struct enumerator in PropertyDictionary<T>.GetEnumerator() by @nareshjo in dotnet/msbuild#14272 * Refresh copy marker when implementation output changes by @AlesProkop in dotnet/msbuild#14231 * Send task-host build process environment as delta by @OvesN in dotnet/msbuild#14126 * Add regression coverage for metadata newline preservation by @VolPlita in dotnet/msbuild#14261 * Fix EmbedInBinlog items with relative paths from child projects by @huulinhnguyen-dev in dotnet/msbuild#13990 * Stop requiring VersionPrefix updates in servicing - insert prerelease versions to VS by @ViktorHofer in dotnet/msbuild#14277 * Fix WriteLinesToFile rewriting unchanged file when custom encoding is used by @huulinhnguyen-dev in dotnet/msbuild#14146 * Enable trim/AOT analyzers for Microsoft.Build and clean up annotations by @JeremyKuhne in dotnet/msbuild#14064 * [automated] Merge branch 'vs18.9' => 'main' by @github-actions[bot] in dotnet/msbuild#14291 * Fix MicroBuild plugin feed URL to use allowed pkgs.dev.azure.com format by @AlesProkop in dotnet/msbuild#14295 * Pass ExcludeRestorePackageImports during restore to avoid redundant evaluations by @ViktorHofer with @Copilot in dotnet/msbuild#14274 * [vs18.7] Update dependencies from dotnet/arcade by @dotnet-maestro[bot] in dotnet/msbuild#13988 * Adopt Clever Test Selection (CTS) as parallel, non-blocking PR pipeline by @jankratochvilcz in dotnet/msbuild#14212 * Harden exceptions when connecting to server by @JanProvaznik in dotnet/msbuild#14292 * Update MicrosoftBuildVersion in analyzer template by @github-actions[bot] in dotnet/msbuild#13886 * Fix MSBuild Server client dropping build result under WaitAny race (#14172) by @JanProvaznik in dotnet/msbuild#14251 * Partially revert #13660: remove NuGet RestoreTask transient TaskHost workaround by @JanProvaznik in dotnet/msbuild#14297 * Disable daily AI credits guardrail for Expert Code Review workflow by @JanProvaznik with @Copilot in dotnet/msbuild#14314 * Localized file check-in by OneLocBuild Task: Build definition ID 9434: Build ID 14614733 by @dotnet-bot in dotnet/msbuild#14246 * Add opt-in partial (stop-after-pass) project evaluation by @ViktorHofer in dotnet/msbuild#14290 * Use partial evaluation for -getProperty/-getItem without a target by @ViktorHofer in dotnet/msbuild#14296 * [main] Source code updates from dotnet/dotnet by @dotnet-maestro[bot] in dotnet/msbuild#14324 * [main] Update dependencies from dotnet/roslyn by @dotnet-maestro[bot] in dotnet/msbuild#14333 * [main] Update dependencies from nuget/nuget.client by @dotnet-maestro[bot] in dotnet/msbuild#14330 * Bump github/gh-aw-actions/setup from 0.82.2 to 0.82.8 by @dependabot[bot] in dotnet/msbuild#14328 * Restrict partial evaluation to ProjectInstance by @ViktorHofer in dotnet/msbuild#14340 ... (truncated) Commits viewable in [compare view](dotnet/msbuild@v18.9.6...v18.10.1). </details> [![Dependabot compatibility score](https://dependabot-badges.githubapp.com/badges/compatibility_score?dependency-name=Microsoft.Build.Utilities.Core&package-manager=nuget&previous-version=18.9.6&new-version=18.10.1)](https://docs.github.com/en/github/managing-security-vulnerabilities/about-dependabot-security-updates#about-compatibility-scores) Dependabot will resolve any conflicts with this PR as long as you don't alter it yourself. You can also trigger a rebase manually by commenting `@dependabot rebase`. 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Copilot AI review requested due to automatic review settings June 13, 2026 00:11

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Comment thread src/Build/BackEnd/Components/Logging/BuildErrorTelemetryTracker.cs Outdated

JeremyKuhne marked this pull request as draft June 14, 2026 23:18

JeremyKuhne mentioned this pull request Jun 17, 2026

Make property functions and reflection-heavy paths trim-compatible #14079

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JeremyKuhne force-pushed the aot-enable-build branch from c720aed to 360ef93 Compare June 17, 2026 21:40

JeremyKuhne force-pushed the aot-enable-build branch from 360ef93 to db37c8a Compare June 28, 2026 19:26

JeremyKuhne marked this pull request as ready for review June 28, 2026 19:38

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Comment thread src/Build/BackEnd/Components/Logging/LoggingService.cs Outdated

JeremyKuhne force-pushed the aot-enable-build branch 4 times, most recently from b138d25 to b0dce1c Compare June 29, 2026 19:41

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Comment thread src/Tasks/BuiltInTasks.cs

JeremyKuhne mentioned this pull request Jul 1, 2026

Make Microsoft.Build.Tasks.CodeAnalysis AOT and single-file clean dotnet/roslyn#84335

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JeremyKuhne added 4 commits July 6, 2026 12:04

JeremyKuhne force-pushed the aot-enable-build branch from b0dce1c to 89e0239 Compare July 6, 2026 19:24

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Enable trim/AOT analyzers for Microsoft.Build and clean up annotations - #14064

Enable trim/AOT analyzers for Microsoft.Build and clean up annotations#14064
JeremyKuhne merged 4 commits into
dotnet:mainfrom
JeremyKuhne:aot-enable-build

JeremyKuhne commented Jun 13, 2026 •

edited

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JeremyKuhne commented Jul 6, 2026

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JeremyKuhne commented Jun 13, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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Summary

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New public API surface

AOT validation

Design criterion: fail observably, never silently

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JeremyKuhne commented Jul 6, 2026

Windows Core failure — investigation

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JeremyKuhne commented Jun 13, 2026 •

edited

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