From 6d499c21e965d0accb235991f3123da5d3649e75 Mon Sep 17 00:00:00 2001
From: Larry Ewing <lewing@microsoft.com>
Date: Fri, 6 Feb 2026 20:03:31 -0600
Subject: [PATCH 1/2] Fix WASM boot config ContentRoot to use
 IntermediateOutputPath

Change the boot config's DefineStaticWebAssets ContentRoot from
wwwroot to  so the asset Identity
points to the actual file location on disk rather than a stale copy
in the output wwwroot folder.

This fixes SRI integrity failures during incremental Blazor WASM builds
where the compressed boot config used a stale fingerprint from the
wwwroot copy instead of the fresh file in obj/.

Fixes aspnetcore#65271
---
 .../build/Microsoft.NET.Sdk.WebAssembly.Browser.targets         | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/mono/nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets b/src/mono/nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets
index b9a8373cf97696..c70df8c1f11ead 100644
--- a/src/mono/nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets
+++ b/src/mono/nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets
@@ -516,7 +516,7 @@ Copyright (c) .NET Foundation. All rights reserved.
       AssetTraitValue="manifest"
       CopyToOutputDirectory="PreserveNewest"
       CopyToPublishDirectory="Never"
-      ContentRoot="$(OutDir)wwwroot"
+      ContentRoot="$(IntermediateOutputPath)"
       BasePath="$(StaticWebAssetBasePath)"
     >
       <Output TaskParameter="Assets" ItemName="_WasmBuildBootConfigStaticWebAsset" />

From 7af79ad302f6245d66d649022aedca0227f435c2 Mon Sep 17 00:00:00 2001
From: Larry Ewing <lewing@microsoft.com>
Date: Fri, 6 Feb 2026 23:28:43 -0600
Subject: [PATCH 2/2] Use boot config output items for preload matching

Replace the fragile FileName-based scanning of all StaticWebAsset items
with direct references to _WasmBuildBootConfigStaticWebAsset and
_WasmPublishBootConfigStaticWebAsset. These items are already produced
by the DefineStaticWebAssets task in _GenerateBuildWasmBootJson and
_AddPublishWasmBootJsonToStaticWebAssets respectively.

The previous approach relied on FileName containing the fingerprint
(e.g. dotnet.FINGERPRINT.js), which is an implementation detail of
how DefineStaticWebAssets computes Identity. Using the pipeline's
own output items is correct regardless of ContentRoot or Identity
format.
---
 .../Microsoft.NET.Sdk.WebAssembly.Browser.targets | 15 ++-------------
 1 file changed, 2 insertions(+), 13 deletions(-)

diff --git a/src/mono/nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets b/src/mono/nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets
index c70df8c1f11ead..2993447c1a3c70 100644
--- a/src/mono/nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets
+++ b/src/mono/nuget/Microsoft.NET.Sdk.WebAssembly.Pack/build/Microsoft.NET.Sdk.WebAssembly.Browser.targets
@@ -582,18 +582,10 @@ Copyright (c) .NET Foundation. All rights reserved.
   </Target>
 
   <Target Name="_AddWasmPreloadBuildProperties" DependsOnTargets="_WasmConfigurePreload;_AddWasmStaticWebAssets" BeforeTargets="GenerateStaticWebAssetsManifest" Condition="'$(_WasmPreloadAssets)' == 'true'">
-    <PropertyGroup>
-      <_WasmBootConfigFileNameWithoutExtension>$([System.IO.Path]::GetFileNameWithoutExtension('$(_WasmBootConfigFileName)'))</_WasmBootConfigFileNameWithoutExtension>
-      <_WasmBootConfigFileExtension>$([System.IO.Path]::GetExtension('$(_WasmBootConfigFileName)'))</_WasmBootConfigFileExtension>
-    </PropertyGroup>
-    <ItemGroup>
-      <_WasmPreloadBuildScriptAsset Include="@(StaticWebAsset)" Condition="'$(_WasmFingerprintAssets)' == 'true' and '$(_WasmFingerprintBootConfig)' == 'true' and '%(AssetKind)' != 'Publish' and '%(FileName)%(Extension)' == '$(_WasmBootConfigFileNameWithoutExtension).%(Fingerprint)$(_WasmBootConfigFileExtension)'" />
-      <_WasmPreloadBuildScriptAsset Include="@(StaticWebAsset)" Condition="('$(_WasmFingerprintAssets)' != 'true' or '$(_WasmFingerprintBootConfig)' != 'true') and '%(AssetKind)' != 'Publish' and '%(FileName)%(Extension)' == '$(_WasmBootConfigFileName)'" />
-    </ItemGroup>
 
     <FilterStaticWebAssetEndpoints
       Endpoints="@(StaticWebAssetEndpoint)"
-      Assets="@(_WasmPreloadBuildScriptAsset)"
+      Assets="@(_WasmBuildBootConfigStaticWebAsset)"
       Filters="@(_WasmPreloadEndpointFilter)"
     >
       <Output TaskParameter="FilteredEndpoints" ItemName="_WasmPreloadBuildScriptAssetEndpoint" />
@@ -612,13 +604,10 @@ Copyright (c) .NET Foundation. All rights reserved.
     </ItemGroup>
   </Target>
   <Target Name="_AddWasmPreloadPublishProperties" DependsOnTargets="_WasmConfigurePreload;_AddPublishWasmBootJsonToStaticWebAssets" BeforeTargets="GenerateStaticWebAssetsPublishManifest" Condition="'$(_WasmPreloadAssets)' == 'true'">
-    <ItemGroup>
-      <_WasmPreloadPublishScriptAsset Include="@(StaticWebAsset)" Condition="'%(AssetKind)' != 'Build' and '%(FileName)%(Extension)' == '$(_WasmPublishBootConfigFileName)'" />
-    </ItemGroup>
 
     <FilterStaticWebAssetEndpoints
       Endpoints="@(StaticWebAssetEndpoint)"
-      Assets="@(_WasmPreloadPublishScriptAsset)"
+      Assets="@(_WasmPublishBootConfigStaticWebAsset)"
       Filters="@(_WasmPreloadEndpointFilter)"
     >
       <Output TaskParameter="FilteredEndpoints" ItemName="_WasmPreloadPublishScriptAssetEndpoint" />