fix: Added WebGL pre build process (#2141)

Author: bitsandfoxes

CHANGELOG.md

@@ -2,8 +2,10 @@
 
 ## Unreleased
 
-### Fixes 
+### Fixes
 
+- When targeting WebGL with an unsupported configuration (i.e. when the exception support is set to `none`), the SDK now shows an error at build time instead of a runtime failure ([#2141](https://github.com/getsentry/sentry-unity/pull/2141))
+- When targeting Desktop Platforms, Sentry-CLI now respects the SDK's debug logging verbosity ([#2138](https://github.com/getsentry/sentry-unity/pull/2138)) 
 - When targeting iOS, the SDK now correctly updates the Sentry CLI options used for debug symbol upload when appending builds ([#2146](https://github.com/getsentry/sentry-unity/pull/2146))
 - When targeting Desktop Platforms, Sentry CLI now respects the SDK's debug logging verbosity ([#2138](https://github.com/getsentry/sentry-unity/pull/2138)) 
 - When targeting iOS and setting `IgnoreCliErrors = true`, the Xcode build will now succeed even if the symbol upload itself failed. This is aimed to allow users to unblock themselves ([#2136](https://github.com/getsentry/sentry-unity/pull/2136)) 

src/Sentry.Unity.Editor/WebGL/BuildPreProcess.cs

@@ -0,0 +1,37 @@
+using Sentry.Extensibility;
+using UnityEditor;
+using UnityEditor.Build;
+using UnityEditor.Build.Reporting;
+using UnityEngine;
+
+namespace Sentry.Unity.Editor.WebGL;
+
+internal class BuildPreProcess : IPreprocessBuildWithReport
+{
+    public int callbackOrder => 1;
+
+    public void OnPreprocessBuild(BuildReport report)
+    {
+        var targetGroup = BuildPipeline.GetBuildTargetGroup(report.summary.platform);
+        if (targetGroup is not BuildTargetGroup.WebGL)
+        {
+            return;
+        }
+
+        if (PlayerSettings.WebGL.exceptionSupport == WebGLExceptionSupport.None)
+        {
+            throw new BuildFailedException("WebGL exception support is set to None. The Sentry SDK requires exception " +
+                "support to function properly. Please change the WebGL exception support setting in Player Settings " +
+                "or disable the Sentry SDK.");
+        }
+        else if (PlayerSettings.WebGL.exceptionSupport != WebGLExceptionSupport.FullWithStacktrace)
+        {
+            var (options, _) = SentryScriptableObject.ConfiguredBuildTimeOptions();
+            var logger = options?.DiagnosticLogger ?? new UnityLogger(options ?? new SentryUnityOptions());
+
+            logger.LogWarning("The SDK requires the Exception Support to be set " +
+                              "'WebGLExceptionSupport.FullWithStacktrace' to be able to provide stack traces when " +
+                              "capturing errors.");
+        }
+    }
+}