Align ITaskItem<T> binding with ValueTypeParser and flag culture-sensitive conversions by baronfel · Pull Request #13974 · dotnet/msbuild

baronfel · 2026-06-05T19:42:23Z

Summary

Expands ITaskItem<T> / TaskItem<T> engine binding beyond path types while keeping the accepted type set aligned with ValueTypeParser.

The binder now accepts:

Directly parsed types: string, bool, AbsolutePath, FileInfo, DirectoryInfo
Convert.ChangeType types: char, numeric primitives, decimal, and DateTime

Enums, nullable value types, Guid, TimeSpan, and custom structs remain unsupported.

Changes

Replaces broad IsValueType checks with an explicit ValueTypeParser-aligned allowlist.
Applies the same validation to scalar and array inputs and outputs for both ITaskItem<T> and concrete TaskItem<T>.
Adds binding coverage for string, MSBuild boolean syntax, and the full supported/unsupported type matrix.
Updates MSBuildTask0009 to match runtime support and recommend only directly parsed types.
Adds MSBuildTask0010 as an error when ITaskItem<T> uses a type parsed through Convert.ChangeType. These conversions use CultureInfo.InvariantCulture, which may not match the task's intended culture. Authors should bind as ITaskItem<string> and parse explicitly with the intended culture.

Dependency status

The preceding PRs (#13971, #13972, and #13973) are merged, and this PR is rebased directly on main.

/cc @baronfel

baronfel · 2026-06-11T14:52:33Z

Note: we don't want this to be any value type - consult w/ @rainersigwald on the allowed subset (likely bool, char (??), enum, etc) and consider loosening at a later date.

@baronfel

…em<T> type arguments (#13973) ## Summary Adds **MSBuildTask0009 (UnsupportedTaskItemType)**: a Roslyn analyzer that fires when a task property uses `ITaskItem<T>` where `T` is not currently supported by MSBuild's task parameter binder. This catches generic type arguments that would fail at runtime. The analyzer currently recognizes `AbsolutePath`, `FileInfo`, and `DirectoryInfo`. Primitive and other value types will be added when the engine-side binding support lands. ## Stacked on - Requires: #13972 (MSBuildTask0006/0007 migration analyzers) - Next: #13974 (value type support) /cc @baronfel --------- Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Extends the engine to accept ITaskItem<T> where T is any value type (int, bool, long, etc.) in addition to path-like types. Uses ValueTypeParser for parsing and formatting. Also adds corresponding unit tests for ITaskItem<int> binding. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Limit typed task item binding to ValueTypeParser-supported types and keep runtime and analyzer validation consistent. Add MSBuildTask0010 as an error for types parsed through Convert.ChangeType so task authors choose culture-explicit parsing instead. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com> Copilot-Session: f684d8fd-b7da-4512-81ad-ca364f87414b

Copilot

Pull request overview

This PR expands MSBuild’s engine-side binding support for ITaskItem<T> / TaskItem<T> to a broader, ValueTypeParser-aligned set of T, and updates the task-authoring analyzers to (1) reflect the new supported set and (2) flag Convert.ChangeType-based bindings as an error (MSBuildTask0010) to steer authors toward explicit parsing.

Changes:

Align runtime type support for ITaskItem<T> / TaskItem<T> with ValueTypeParser via explicit allowlists and consistent validation across scalar/array inputs & outputs.
Extend the Roslyn analyzer to recognize the expanded support matrix (MSBuildTask0009) and add MSBuildTask0010 for Convert.ChangeType-based T.
Add/expand unit tests for analyzer diagnostics and engine binding (including scalar/array input and output coverage).

Reviewed changes

Copilot reviewed 13 out of 13 changed files in this pull request and generated 3 comments.

Show a summary per file

File	Description
src/TaskAnalyzer/UnsupportedTaskItemTypeAnalyzer.cs	Adds MSBuildTask0010 reporting and updates supported diagnostics for `ITaskItem<T>` type arguments.
src/TaskAnalyzer/SupportedTaskItemTypes.cs	Centralizes analyzer-side allowlists (directly-parsed vs `Convert.ChangeType` special types).
src/TaskAnalyzer/README.md	Documents the new diagnostic (MSBuildTask0010) and updates supported type guidance.
src/TaskAnalyzer/DiagnosticIds.cs	Adds the MSBuildTask0010 diagnostic ID constant.
src/TaskAnalyzer/DiagnosticDescriptors.cs	Introduces the MSBuildTask0010 descriptor and refines MSBuildTask0009 messaging.
src/TaskAnalyzer/AnalyzerReleases.Unshipped.md	Records MSBuildTask0010 as a new, unshipped analyzer rule.
src/TaskAnalyzer.Tests/UnsupportedTaskItemTypeAnalyzerTests.cs	Adds test coverage for MSBuildTask0010 and updates MSBuildTask0009 expectations.
src/Shared/TaskParameterTypeVerifier.cs	Updates verifier helpers to use supported-type detection for `ITaskItem<T>` / `TaskItem<T>`.
src/Framework/TaskItemTypeDetector.cs	Implements the runtime supported-type allowlist and generic `TaskItem<T>` detection helpers.
src/Build/BackEnd/TaskExecutionHost/TaskExecutionHost.cs	Expands `ITaskItem<T>` / `TaskItem<T>` parameter handling beyond path-like types.
src/Build.UnitTests/BackEnd/TaskParameterTypeVerifier_Tests.cs	Adds matrix tests for supported/unsupported `T` for both `ITaskItem<T>` and `TaskItem<T>`.
src/Build.UnitTests/BackEnd/TaskExecutionHost_Tests.cs	Adds binding coverage for `TaskItem<T>` scalar/array inputs and outputs.
src/Build.UnitTests/BackEnd/TaskBuilderTestTask.cs	Extends the test task with new `ITaskItem<int>` input/output properties used by host tests.

State that Convert.ChangeType binding uses CultureInfo.InvariantCulture and clarify that the string binding test verifies the item value rather than CLR reference identity. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com> Copilot-Session: f684d8fd-b7da-4512-81ad-ca364f87414b

OvesN

LGTM, just one comment

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com> Copilot-Session: f684d8fd-b7da-4512-81ad-ca364f87414b

## Summary - add `MSBuildTask0011` at Info severity for concrete `IMultiThreadableTask` implementations that do not expose a public single-`TaskEnvironment` constructor - cover valid, invalid, abstract, and inherited-constructor cases - document the recommended constructor-injection pattern in the analyzer README and thread-safe task specification Replaces #14400, which GitHub automatically closed when its stacked base branch was deleted after #14315 merged. The branch is now rebased directly onto `main`. The rule moved from the originally proposed ID 0010 to 0011 because `main` assigned `MSBuildTask0010` in #13974. ## Compatibility The task-authoring analyzer is currently non-shipping/opt-in, and this diagnostic defaults to Info severity, so it does not break builds using warnings-as-errors. No ChangeWave is needed. ## Performance Measured with the BenchmarkDotNet harness from #14387 in a disposable integration checkout, using the default job on an Apple M4 Max with .NET 10.0.8 / SDK 10.0.300. `MSBuildTask0009` is the closest existing symbol-action analyzer. | Diagnostics | MSBuildTask0009 | MSBuildTask0011 | 0009 allocated | 0011 allocated | |---:|---:|---:|---:|---:| | 1 | 358.4 us | 357.9 us | 352.02 KB | 352.26 KB | | 10 | 563.5 us | 588.8 us | 693.73 KB | 683.04 KB | | 100 | 2.731 ms | 2.835 ms | 3,570.28 KB | 3,584.23 KB | The initial no-reference path measured 48.08 us / 32.41 KB. Short-circuiting after the mandatory `IMultiThreadableTask` lookup reduced that to 35.52 us / 30.56 KB, close to `MSBuildTask0009` at 31.46 us / 30.56 KB. Diagnostic time, allocations, and 1/10/100 scaling are comparable, so no further complexity is justified. ## Validation - `./build.sh -v quiet` - `dotnet test --project src/TaskAnalyzer.Tests/TaskAnalyzer.Tests.csproj -c Release` - #14387 BenchmarkDotNet no-op and exact-count 1/10/100 diagnostic scenarios Fixes #14378

baronfel mentioned this pull request Jun 5, 2026

Add Roslyn analyzer (MSBuildTask0009) warning for unsupported ITaskItem<T> type arguments #13973

Merged

baronfel changed the title ~~Expand ITaskItem<T> binding to support any value type T~~ Expand ITaskItem<T> binding to support arbitrary value types (int, bool, etc.) Jun 5, 2026

baronfel force-pushed the typed-params/unsupported-type-analyzer branch from 066020c to a06f9e6 Compare June 5, 2026 21:12

baronfel force-pushed the typed-params/value-type-support branch from 676b7c9 to 1460831 Compare June 5, 2026 21:13

baronfel force-pushed the typed-params/unsupported-type-analyzer branch from a06f9e6 to 7531acb Compare June 5, 2026 21:22

baronfel force-pushed the typed-params/value-type-support branch from 1460831 to 2e0738d Compare June 5, 2026 21:27

baronfel requested a review from a team June 8, 2026 15:00

baronfel force-pushed the typed-params/unsupported-type-analyzer branch from 7531acb to 92f144c Compare July 1, 2026 17:32

baronfel force-pushed the typed-params/value-type-support branch from 2e0738d to dffb8c8 Compare July 1, 2026 17:32

OvesN requested changes Jul 10, 2026

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Comment thread src/Framework/TaskItemTypeDetector.cs Outdated

Comment thread src/Framework/TaskItemTypeDetector.cs Outdated

baronfel force-pushed the typed-params/unsupported-type-analyzer branch from 92f144c to 0cf9297 Compare July 13, 2026 22:06

Base automatically changed from typed-params/unsupported-type-analyzer to main July 14, 2026 18:31

baronfel force-pushed the typed-params/value-type-support branch from dffb8c8 to 9e37fa5 Compare July 14, 2026 18:45

baronfel changed the title ~~Expand ITaskItem<T> binding to support arbitrary value types (int, bool, etc.)~~ Align ITaskItem<T> binding with ValueTypeParser and flag culture-sensitive conversions Jul 14, 2026

baronfel requested a review from OvesN July 14, 2026 22:00

baronfel added User Experience Area: Engine Issues impacting the core execution of targets and tasks. Area: Analyzer labels Jul 14, 2026

baronfel marked this pull request as ready for review July 15, 2026 14:22

Copilot AI review requested due to automatic review settings July 15, 2026 14:22

Copilot started reviewing on behalf of baronfel July 15, 2026 14:23 View session

Copilot AI reviewed Jul 15, 2026

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Comment thread src/Build.UnitTests/BackEnd/TaskExecutionHost_Tests.cs

Comment thread src/TaskAnalyzer/DiagnosticDescriptors.cs Outdated

Comment thread src/TaskAnalyzer/README.md

OvesN approved these changes Jul 16, 2026

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Comment thread src/Shared/TaskParameterTypeVerifier.cs Outdated

Consolidate typed task item type detection

80c651e

Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com> Copilot-Session: f684d8fd-b7da-4512-81ad-ca364f87414b

OvesN approved these changes Jul 16, 2026

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baronfel enabled auto-merge (squash) July 16, 2026 17:15

baronfel merged commit 566cbd8 into main Jul 16, 2026
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baronfel deleted the typed-params/value-type-support branch July 16, 2026 19:53

jankratochvilcz mentioned this pull request Jul 16, 2026

Add analyzer for TaskEnvironment constructor injection #14401

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dotnet-maestro Bot mentioned this pull request Jul 17, 2026

[main] Source code updates from dotnet/msbuild dotnet/dotnet#7806

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This was referenced Jul 22, 2026

[Flaky Test] Microsoft.Build.Engine.UnitTests.NetTaskHost_E2E_Tests.NetTaskHost_SymlinkedSdkPath_ShouldNotCauseMSB4216 #14393

Open

[Flaky Test] Microsoft.Build.UnitTests.TerminalLogger_Tests.ReplayBinaryLogWithFewerNodesThanOriginalBuild #14394

Open

OvesN mentioned this pull request Jul 23, 2026

Migrate existing tasks to typed task parameters OvesN/msbuild#6

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Align ITaskItem<T> binding with ValueTypeParser and flag culture-sensitive conversions - #13974

Align ITaskItem<T> binding with ValueTypeParser and flag culture-sensitive conversions#13974
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