fix: Serilog integration captures structured log when event with exception has been captured

CHANGELOG.md

@@ -14,6 +14,10 @@
 - The SDK now provides a `IsSessionActive` to allow checking the session state ([#4662](https://github.com/getsentry/sentry-dotnet/pull/4662))
 - The SDK now makes use of the new SessionEndStatus `Unhandled` when capturing an unhandled but non-terminal exception, i.e. through the UnobservedTaskExceptionIntegration ([#4633](https://github.com/getsentry/sentry-dotnet/pull/4633))
 
+### Fixes
+
+- The `Serilog` integration captures _Structured Logs_ (when enabled) independently of captured Events and added Breadcrumbs ([#4691](https://github.com/getsentry/sentry-dotnet/pull/4691))
+
 ## 6.0.0-preview.2
 
 ### BREAKING CHANGES

src/Sentry.Serilog/SentrySink.cs

@@ -105,6 +105,7 @@ private void InnerEmit(LogEvent logEvent)
         var exception = logEvent.Exception;
         var template = logEvent.MessageTemplate.Text;
         var formatted = FormatLogEvent(logEvent);
+        var addedBreadcrumb = false;
 
         if (logEvent.Level >= _options.MinimumEventLevel)
         {
@@ -137,11 +138,11 @@ private void InnerEmit(LogEvent logEvent)
             // Capturing exception events adds a breadcrumb automatically... we don't want to add another one
             if (exception != null)
             {
-                return;
+                addedBreadcrumb = true;
             }
         }
 
-        if (logEvent.Level >= _options.MinimumBreadcrumbLevel)
+        if (!addedBreadcrumb && logEvent.Level >= _options.MinimumBreadcrumbLevel)
         {
             Dictionary<string, string>? data = null;
             if (exception != null && !string.IsNullOrWhiteSpace(formatted))

test/Sentry.Serilog.Tests/SentrySinkTests.Structured.cs

@@ -134,4 +134,36 @@ public void Emit_StructuredLogging_LogEvent(bool withActiveSpan)
         log.TryGetAttribute("property.Structure-Property", out object? structure).Should().BeTrue();
         structure.Should().Be("""[42, "42"]""");
     }
+
+    [Fact]
+    public void Emit_StructuredLoggingWithException_NoBreadcrumb()
+    {
+        InMemorySentryStructuredLogger capturer = new();
+        _fixture.Hub.Logger.Returns(capturer);
+        _fixture.Options.Experimental.EnableLogs = true;
+
+        var sut = _fixture.GetSut();
+        var logger = new LoggerConfiguration().WriteTo.Sink(sut).MinimumLevel.Verbose().CreateLogger();
+
+        logger.Write(LogEventLevel.Error, new Exception("expected message"), "Message");
+
+        _fixture.Scope.Breadcrumbs.Should().BeEmpty();
+        capturer.Logs.Should().ContainSingle().Which.Message.Should().Be("Message");
+    }
+
+    [Fact]
+    public void Emit_StructuredLoggingWithoutException_LeavesBreadcrumb()
+    {
+        InMemorySentryStructuredLogger capturer = new();
+        _fixture.Hub.Logger.Returns(capturer);
+        _fixture.Options.Experimental.EnableLogs = true;
+
+        var sut = _fixture.GetSut();
+        var logger = new LoggerConfiguration().WriteTo.Sink(sut).MinimumLevel.Verbose().CreateLogger();
+
+        logger.Write(LogEventLevel.Error, (Exception?)null, "Message");
+
+        _fixture.Scope.Breadcrumbs.Should().ContainSingle().Which.Message.Should().Be("Message");
+        capturer.Logs.Should().ContainSingle().Which.Message.Should().Be("Message");
+    }
 }