From b980ee09713975013ee9c5dbab8a470066d145d7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Marek=20Fi=C5=A1era?= <mara@neptuo.com>
Date: Tue, 19 May 2026 08:32:20 +0000
Subject: [PATCH] Fix WASM CoreCLR VFS content files missing from boot JSON

During CoreCLR WASM nested publish, the _WriteBuildWasmBootJsonFile
target (added by #125367 with Inputs/Outputs incrementalism) would
write the boot JSON without VFS entries (because LinkContentToWwwroot
is skipped when WasmBuildingForNestedPublish=true). Then in the outer
build, the Inputs/Outputs check would find the stale output and skip
regeneration, leaving the final boot JSON without VFS content files.

This caused tests relying on content files (like testdataset1.xml) to
fail with DirectoryNotFoundException on WASM CoreCLR.

Fix: Skip _WriteBuildWasmBootJsonFile and _GenerateBuildWasmBootJson
during nested publish. The nested publish doesn't need the build boot
JSON (it only returns WasmAssembliesFinal/WasmNativeAsset), and
skipping it ensures the outer build writes the correct boot JSON with
VFS entries.

Fixes #128293

Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
---
 .../Microsoft.NET.Sdk.WebAssembly.Browser.targets   | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 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 2cd9e68f92b974..d462dfad666eb0 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
@@ -680,9 +680,14 @@ Copyright (c) .NET Foundation. All rights reserved.
 
   <!-- Write the boot JSON file for the build.
        This target is incremental: when all inputs (assemblies, static web assets, VFS files,
-       config files, extensions, property stamp) are older than the output, the target is skipped. -->
+       config files, extensions, property stamp) are older than the output, the target is skipped.
+       Skipped during nested publish: the nested publish runs the full Build chain which would
+       create the boot JSON without VFS entries (LinkContentToWwwroot is skipped). If we wrote
+       it here, the outer build's Inputs/Outputs check would find the stale output and skip
+       regeneration, leaving the final boot JSON without VFS content files. -->
   <Target Name="_WriteBuildWasmBootJsonFile"
     DependsOnTargets="_WriteWasmBootJsonBuildPropertyStamp"
+    Condition="'$(WasmBuildingForNestedPublish)' != 'true'"
     Inputs="@(IntermediateAssembly);@(WasmStaticWebAsset);@(_WasmJsModuleCandidatesForBuild);@(_WasmFilesToIncludeInFileSystemStaticWebAsset);@(_WasmJsConfigStaticWebAsset);@(_WasmDotnetJsForBuild);@(WasmBootConfigExtension);$(ProjectRuntimeConfigFilePath);$(MSBuildProjectFullPath);$(MSBuildThisFileFullPath);$(_WebAssemblySdkTasksAssembly);$(IntermediateOutputPath)wasm-bootjson-build.stamp"
     Outputs="$(_WasmBuildBootJsonPath)">
 
@@ -733,8 +738,10 @@ Copyright (c) .NET Foundation. All rights reserved.
   </Target>
 
   <!-- Define the boot config file as a static web asset and create endpoints.
-       This target always runs to ensure items are populated even when _WriteBuildWasmBootJsonFile is skipped. -->
-  <Target Name="_GenerateBuildWasmBootJson" DependsOnTargets="_WriteBuildWasmBootJsonFile">
+       This target always runs to ensure items are populated even when _WriteBuildWasmBootJsonFile is skipped.
+       Skipped during nested publish (same reason as _WriteBuildWasmBootJsonFile). -->
+  <Target Name="_GenerateBuildWasmBootJson" DependsOnTargets="_WriteBuildWasmBootJsonFile"
+    Condition="'$(WasmBuildingForNestedPublish)' != 'true'">
 
     <ItemGroup>
       <!-- Track boot JSON for clean operations even when _WriteBuildWasmBootJsonFile was skipped -->