Fix WASM publish path for Framework SourceType materialization by lewing · Pull Request #126210 · dotnet/runtime

lewing · 2026-03-27T17:17:32Z

Summary

PR #125329 added Framework SourceType handling in Browser.targets for the build path, but the publish path (ProcessPublishFilesForWasm) was not updated. When a server hosts multiple Blazor WASM clients and publishes, DiscoverPrecompressedAssets crashes with duplicate Identity keys for shared runtime pack files (dotnet.js.map, ICU data, etc.).

Root Cause

The publish-time ConvertDllsToWebcil call (line 790) did not capture PassThroughCandidates, so pass-through files weren't routed through DefineStaticWebAssets(SourceType="Framework") + UpdatePackageStaticWebAssets for per-project materialization.

Fix

Mirror the build-time Framework materialization in ProcessPublishFilesForWasm:

Capture PassThroughCandidates from publish-time ConvertDllsToWebcil
Remove pass-throughs from webcil candidates
Route through DefineStaticWebAssets(SourceType="Framework", AssetKind="Publish")
Route through UpdatePackageStaticWebAssets for materialization
Set AssetMode=All so materialized assets flow to the server

Testing

Added MultiClientHostedPublish test (complements existing MultiClientHostedBuild)
Fixes Publish_HostingMultipleBlazorWebApps_Works in sdk#53613

Dependencies

Requires SDK support for SourceType="Framework" from sdk#53135 (already merged).

… solutions Multi-WASM-client solutions crash with duplicate Identity keys in DiscoverPrecompressedAssets because pass-through files (JS, maps, ICU, native wasm) share the same NuGet cache path across projects. Instead of manually copying pass-throughs, use the SWA Framework SourceType convention: DefineStaticWebAssets registers them as SourceType="Framework", then UpdatePackageStaticWebAssets materializes them to per-project obj/fx/{SourceId}/ directories, transforming metadata (SourceType→Discovered, SourceId→PackageId, AssetMode→CurrentProject) and giving each project a unique Identity. This approach: - Eliminates manual Copy tasks from Browser.targets - Leverages the SDK's MaterializeFrameworkAsset for timestamp-based incremental copies - Properly models the relationship: framework assets adopted by each consuming project - Works with and without WebCil enabled Depends on dotnet/sdk#53135 for Framework SourceType support in the SDK. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

- Add PassThroughCandidates output to ConvertDllsToWebcil task so the task itself classifies which files are pass-throughs (non-DLL files from shared locations like the NuGet cache) vs converted webcil files. This replaces the fragile MSBuild string-comparison split that checked StartsWith(_WasmBuildWebcilPath) and incorrectly classified native build outputs in obj/wasm/for-build/ as Framework candidates. - Set AssetMode=All on materialized framework assets so they flow through project references to the host/server project in Blazor WASM hosted scenarios. UpdatePackageStaticWebAssets defaults to CurrentProject which prevents the server project from seeing client framework assets during publish. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Clarify that WasmNativeBuildOutput exclusion only applies when IsEnabled is true. When IsEnabled is false, all candidates appear unfiltered. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

…ToOutputDirectory Two fixes: 1. ConvertDllsToWebcil: When IsEnabled=false, apply the same filtering for PassThroughCandidates as the enabled path — only non-DLL items without WasmNativeBuildOutput metadata qualify as Framework pass-throughs. Previously all candidates (including DLLs) were marked as pass-throughs, causing them all to go through Framework materialization which triggered NETSDK1147 workload detection in NoWebcil/NoWorkload test configurations. 2. Browser.targets: Set CopyToOutputDirectory=PreserveNewest on materialized framework assets after UpdatePackageStaticWebAssets. The SDK task defaults materialized assets to CopyToOutputDirectory= Never, but WASM framework files (dotnet.native.js, ICU data, etc.) must be copied to bin/wwwroot/_framework for the app to work. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Validates that two Blazor WASM client projects can be built by a single server project without duplicate static web asset Identity collisions. This is the scenario that the Framework SourceType + UpdatePackageStaticWebAssets materialization path was designed to fix. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

The build path correctly routes WASM pass-through files (JS, maps, ICU data) through DefineStaticWebAssets(SourceType="Framework") and UpdatePackageStaticWebAssets for per-project materialization. However, the publish path (ProcessPublishFilesForWasm) was not updated, causing DiscoverPrecompressedAssets to crash with duplicate Identity keys when a server project hosts multiple Blazor WASM clients. Mirror the build-time Framework materialization in the publish path: - Capture PassThroughCandidates from publish-time ConvertDllsToWebcil - Remove pass-throughs from webcil candidates - Route through DefineStaticWebAssets(SourceType="Framework", AssetKind="Publish") - Route through UpdatePackageStaticWebAssets for per-project materialization - Set AssetMode=All so materialized assets flow to the server Also add MultiClientHostedPublish test to validate the publish path alongside the existing MultiClientHostedBuild test. Fixes the Publish_HostingMultipleBlazorWebApps_Works failure in sdk#53613. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

lewing · 2026-03-27T17:21:41Z

Closing — branch had stale history from merged #125329. Reopening with clean branch.

Copilot

Pull request overview

This PR fixes multi-client Blazor WASM publish failures by extending the existing Framework SourceType materialization approach (previously applied to build) into the publish pipeline, preventing duplicate static web asset Identity collisions for shared runtime-pack files.

Changes:

Extend ConvertDllsToWebcil to also output PassThroughCandidates for Framework materialization.
Update Microsoft.NET.Sdk.WebAssembly.Browser.targets publish path (ProcessPublishFilesForWasm) to classify pass-through assets as Framework and materialize them per project via UpdatePackageStaticWebAssets.
Add new build and publish tests validating multi-client hosted scenarios.

Reviewed changes

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

File	Description
src/tasks/Microsoft.NET.Sdk.WebAssembly.Pack.Tasks/ConvertDllsToWebCil.cs	Adds `PassThroughCandidates` output to distinguish pass-through assets needing Framework materialization.
src/mono/nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets	Mirrors build-time Framework materialization in publish pipeline; avoids duplicate `Identity` collisions during publish.
src/mono/wasm/Wasm.Build.Tests/Blazor/MiscTests.cs	Adds `MultiClientHostedBuild` and `MultiClientHostedPublish` coverage for multi-client hosted build/publish.

Copilot · 2026-03-27T17:27:04Z

src/mono/wasm/Wasm.Build.Tests/Blazor/MiscTests.cs

+        string rootDir = Path.GetDirectoryName(_projectDir)!;
+        string client1Dir = _projectDir;
+        string client2Dir = Path.Combine(rootDir, "App2");
+        string serverDir = Path.Combine(rootDir, "Server");
+


Same cleanup concern as in MultiClientHostedBuild: App2 and Server are created under rootDir (parent of _projectDir), so the standard per-test cleanup that deletes _projectDir won't remove them. Prefer nesting these under _projectDir or otherwise ensuring rootDir is cleaned up to avoid leaving large publish outputs behind.

Copilot · 2026-03-27T17:27:05Z

src/tasks/Microsoft.NET.Sdk.WebAssembly.Pack.Tasks/ConvertDllsToWebCil.cs

        Directory.Delete(tmpDir, true);

        WebcilCandidates = webcilCandidates.ToArray();
+        PassThroughCandidates = passThroughCandidates.ToArray();
        return true;


Directory.Delete(tmpDir, true) is outside the conversion loop's try/catch. If a conversion throws and the method returns early, tmpDir is left behind. Consider restructuring Execute to use a try/finally around the tmpDir lifetime (and delete tmpDir in the finally, ideally best-effort) so temp directories don't accumulate on failures.

Copilot · 2026-03-27T17:27:05Z

src/mono/wasm/Wasm.Build.Tests/Blazor/MiscTests.cs

+        // _projectDir is now .../App. Go up to the root and create a second client + server.
+        string rootDir = Path.GetDirectoryName(_projectDir)!;


These tests create App2 and Server as siblings of _projectDir (under rootDir). Per-test cleanup deletes _projectDir (the App directory) but will leave App2/Server behind, which can bloat temp storage across runs. Consider creating these directories under _projectDir so they get cleaned up automatically, or adjust cleanup to delete rootDir (e.g., via a try/finally that updates _projectDir to rootDir).

Suggested change

// _projectDir is now .../App. Go up to the root and create a second client + server.

string rootDir = Path.GetDirectoryName(_projectDir)!;

// _projectDir is now .../App. Create a second client + server under this directory so they get cleaned up.

string rootDir = _projectDir;

lewing and others added 11 commits March 9, 2026 09:01

Merge branch 'main' into fix-wasm-framework-sourcetype

91040a0

Merge branch 'main' into fix-wasm-framework-sourcetype

2965259

Temporarily bump the sdk for testing

69c5452

Merge branch 'main' into fix-wasm-framework-sourcetype

7f518a5

Merge branch 'main' into fix-wasm-framework-sourcetype

2c63e09

Fix PassThroughCandidates XML doc to match IsEnabled=false behavior

0d9edce

Clarify that WasmNativeBuildOutput exclusion only applies when IsEnabled is true. When IsEnabled is false, all candidates appear unfiltered. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>

Copilot AI review requested due to automatic review settings March 27, 2026 17:17

github-actions bot added the area-Build-mono label Mar 27, 2026

dotnet-policy-service bot assigned lewing Mar 27, 2026

Copilot started reviewing on behalf of lewing March 27, 2026 17:18 View session

lewing closed this Mar 27, 2026

Copilot AI reviewed Mar 27, 2026

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Fix WASM publish path for Framework SourceType materialization#126210

Fix WASM publish path for Framework SourceType materialization#126210
lewing wants to merge 11 commits intodotnet:mainfrom
lewing:fix-wasm-framework-sourcetype

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		// _projectDir is now .../App. Go up to the root and create a second client + server.
		string rootDir = Path.GetDirectoryName(_projectDir)!;

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lewing commented Mar 27, 2026

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