Copydotnet.d.ts to wwwroot on build/publish.

[ilonatommy]

Fixes #77174.

[JakeYallop]

Its also worth pointing that dotnet.d.ts is currently explicitly removed from the build via:

_WasmBuildFilesToRemove:

runtime/src/mono/nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets

Line 279 in 7ab1ed3

<Output TaskParameter="FilesToRemove" ItemName="_WasmBuildFilesToRemove" />

Which is an output from the ComputeWasmBuildAssets task, in that task:

runtime/src/tasks/Microsoft.NET.Sdk.WebAssembly.Pack.Tasks/ComputeWasmBuildAssets.cs

Line 93 in 7ab1ed3

if (AssetsComputingHelper.ShouldFilterCandidate(candidate, TimeZoneSupport, InvariantGlobalization, LoadFullICUData, CopySymbols, customIcuCandidateFilename, EnableThreads, EnableDiagnostics, EmitSourceMap, out var reason))

runtime/src/tasks/Microsoft.NET.Sdk.WebAssembly.Pack.Tasks/AssetsComputingHelper.cs

Line 74 in 7ab1ed3

".ts" when fromMonoPackage && fileName == "dotnet.d" => "dotnet type definition is not used by Blazor",

[Copilot]

Pull Request Overview

Adds an opt-in MSBuild property to copy the generated dotnet.d.ts TypeScript definition file into a WebAssembly project's wwwroot during build, addressing issue #77174.

• Introduces WasmEmitTypeScriptDefinitions property (default false) in relevant .targets.
• Adds MSBuild target _EnsureDotnetTypeScriptDefinitions to perform the conditional copy.
• Adds a test validating the file copy on build (Debug/Release).

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 4 comments.

File	Description
src/mono/wasm/build/WasmApp.Common.targets	Documents and defines the new WasmEmitTypeScriptDefinitions property.
src/mono/nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets	Adds property default again and new target to copy dotnet.d.ts into wwwroot.
src/mono/wasm/Wasm.Build.Tests/Templates/WasmTemplateTests.cs	Adds test ensuring dotnet.d.ts is copied on build when the property is enabled.

[maraf]

Suggested change

<WasmEmitTypeScriptDefinitions Condition="'$(WasmEmitTypeScriptDefinitions)' == ''">false</WasmEmitTypeScriptDefinitions>

There is no need to set the property here as well

[ilonatommy]

Because src\mono\wasm\build\WasmApp.Common.targets is imported in workloads and src\mono\nuget\Microsoft.NET.Sdk.WebAssembly.Pack\build\Microsoft.NET.Sdk.WebAssembly.Browser.targets is imported generally in runtime pack?

[ilonatommy]

If so, then this doc in the top of workload-shipped targets should keep WasmEmitTypeScriptDefinitions. Right?

[ilonatommy]

WBT fail, even though manual run of dotnet build on the WBT project succeeds:
log dotnet.d.ts should be created at /root/helix/work/workitem/e/wbt artifacts/tsdefs_Debug_False_h1qa4fpe_vyr_鿀蜒枛遫䡫煉/wwwroot/dotnet.d.ts after the build with WasmEmitTypeScriptDefinitions=true