[wasm][tests] Enable line numbers in stack traces (#50893)

docs/workflow/testing/libraries/testing-wasm.md

@@ -144,6 +144,12 @@ At the moment supported values are:
 
 By default, `chrome` browser is used.
 
+## Debugging
+
+### Getting more information
+
+- Line numbers: add `/p:DebuggerSupport=true` to the command line, for `Release` builds. It's enabled by default for `Debug` builds.
+
 ## Kicking off outer loop tests from GitHub Interface
 
 Add the following to the comment of a PR.

eng/testing/tests.wasm.targets

@@ -2,6 +2,7 @@
   <!-- We need to set this in order to get extensibility on xunit category traits and other arguments we pass down to xunit via MSBuild properties -->
   <PropertyGroup>
     <BundleTestAppTargets>$(BundleTestAppTargets);BundleTestWasmApp</BundleTestAppTargets>
+    <DebuggerSupport Condition="'$(DebuggerSupport)' == '' and '$(Configuration)' == 'Debug'">true</DebuggerSupport>
   </PropertyGroup>
 
   <PropertyGroup Condition="'$(RunScriptCommand)' == ''">
@@ -27,7 +28,9 @@
     <UseSystemResourceKeys>true</UseSystemResourceKeys>
     <EnableUnsafeUTF7Encoding>false</EnableUnsafeUTF7Encoding>
     <HttpActivityPropagationSupport>false</HttpActivityPropagationSupport>
-    <DebuggerSupport>false</DebuggerSupport>
+
+    <!-- we want to default to what Blazor has, except if we are building in Debug config -->
+    <DebuggerSupport Condition="'$(Configuration)' != 'Debug'">false</DebuggerSupport>
   </PropertyGroup>
 
   <!-- Don't include InTree.props here, because the test projects themselves can set the target* properties -->
@@ -62,6 +65,9 @@
       <WasmInvariantGlobalization>$(InvariantGlobalization)</WasmInvariantGlobalization>
       <WasmGenerateRunV8Script>true</WasmGenerateRunV8Script>
       <WasmNativeStrip>false</WasmNativeStrip>
+
+      <WasmNativeDebugSymbols Condition="'$(DebuggerSupport)' == 'true' and '$(WasmNativeDebugSymbols)' == ''">true</WasmNativeDebugSymbols>
+      <WasmDebugLevel Condition="'$(DebuggerSupport)' == 'true' and '$(WasmDebugLevel)' == ''">-1</WasmDebugLevel>
     </PropertyGroup>
 
     <ItemGroup>
@@ -79,4 +85,17 @@
       <WasmFilesToIncludeInFileSystem Include="@(WasmFilesToIncludeFromPublishDir -> '$(PublishDir)%(Identity)')" />
     </ItemGroup>
   </Target>
+
+  <!-- linker automatically picks up the .pdb files, but they are not added to the publish list.
+       Add them explicitly here, so they can be used with WasmAppBuilder -->
+  <Target Name="AddPdbFilesToPublishList" AfterTargets="ILLink" Condition="'$(DebuggerSupport)' == 'true'">
+    <ItemGroup>
+      <_PdbFilesToCheck Include="$([System.IO.Path]::ChangeExtension('%(ResolvedFileToPublish.Identity)', '.pdb'))"
+                        Condition="'%(ResolvedFileToPublish.Extension)' == '.dll'" />
+
+      <ResolvedFileToPublish Include="@(_PdbFilesToCheck)"
+                             Condition="Exists(%(_PdbFilesToCheck.Identity))"
+                             RelativePath="%(_PdbFilesToCheck.FileName)%(_PdbFilesToCheck.Extension)" />
+    </ItemGroup>
+  </Target>
 </Project>

src/mono/wasm/build/WasmApp.targets

@@ -20,7 +20,12 @@
       - $(WasmNativeStrip)   - Whenever to strip the native executable. Defaults to true.
       - $(WasmLinkIcalls)    - Whenever to link out unused icalls. Defaults to $(WasmBuildNative).
       - $(RunAOTCompilation) - Defaults to false.
+
       - $(WasmDebugLevel)
+                              > 0 enables debugging and sets the debug log level to debug_level
+                              == 0 disables debugging and enables interpreter optimizations
+                              < 0 enabled debugging and disables debug logging.
+
       - $(WasmNativeDebugSymbols) - Build with native debug symbols, useful only with `$(RunAOTCompilation)`, or `$(WasmBuildNative)`
                                     Defaults to true.
       - $(WasmDedup)         - Whenever to dedup generic instances when using AOT. Defaults to true.

src/tasks/WasmAppBuilder/WasmAppBuilder.cs

@@ -150,7 +150,7 @@ public override bool Execute ()
         foreach (var assembly in _assemblies)
         {
             FileCopyChecked(assembly, Path.Join(asmRootPath, Path.GetFileName(assembly)), "Assemblies");
-            if (DebugLevel > 0)
+            if (DebugLevel != 0)
             {
                 var pdb = assembly;
                 pdb = Path.ChangeExtension(pdb, ".pdb");
@@ -173,7 +173,7 @@ public override bool Execute ()
         foreach (var assembly in _assemblies)
         {
             config.Assets.Add(new AssemblyEntry(Path.GetFileName(assembly)));
-            if (DebugLevel > 0) {
+            if (DebugLevel != 0) {
                 var pdb = assembly;
                 pdb = Path.ChangeExtension(pdb, ".pdb");
                 if (File.Exists(pdb))