Fixing bridge API bug

src/OpenTelemetry.Exporter.OpenTelemetryProtocol/CHANGELOG.md

@@ -12,6 +12,10 @@ Notes](../../RELEASENOTES.md).
   exports are correctly marked as successful.
   ([#6099](https://github.com/open-telemetry/opentelemetry-dotnet/pull/6099))
 
+* Fixed a bug in logging bridge API where the \{OriginalFormat\} attribute would
+  overwrite `Body` of the emitted `LogRecordData`.
+  ([#6113](https://github.com/open-telemetry/opentelemetry-dotnet/pull/6113))
+
 ## 1.11.1
 
 Released 2025-Jan-22

src/OpenTelemetry.Exporter.OpenTelemetryProtocol/Implementation/Serializer/ProtobufOtlpLogSerializer.cs

@@ -207,13 +207,11 @@ internal static int WriteLogRecord(byte[] buffer, int writePosition, SdkLimitOpt
         }
 
         bool bodyPopulatedFromFormattedMessage = false;
-        bool isLogRecordBodySet = false;
 
         if (logRecord.FormattedMessage != null)
         {
             otlpTagWriterState.WritePosition = WriteLogRecordBody(otlpTagWriterState.Buffer, otlpTagWriterState.WritePosition, logRecord.FormattedMessage.AsSpan());
             bodyPopulatedFromFormattedMessage = true;
-            isLogRecordBodySet = true;
         }
 
         if (logRecord.Attributes != null)
@@ -226,21 +224,12 @@ internal static int WriteLogRecord(byte[] buffer, int writePosition, SdkLimitOpt
                 if (attribute.Key.Equals("{OriginalFormat}") && !bodyPopulatedFromFormattedMessage)
                 {
                     otlpTagWriterState.WritePosition = WriteLogRecordBody(otlpTagWriterState.Buffer, otlpTagWriterState.WritePosition, (attribute.Value as string).AsSpan());
-                    isLogRecordBodySet = true;
                 }
                 else
                 {
                     AddLogAttribute(state, attribute);
                 }
             }
-
-            // Supports setting Body directly on LogRecord for the Logs Bridge API.
-            if (!isLogRecordBodySet && logRecord.Body != null)
-            {
-                // If {OriginalFormat} is not present in the attributes,
-                // use logRecord.Body if it is set.
-                otlpTagWriterState.WritePosition = WriteLogRecordBody(otlpTagWriterState.Buffer, otlpTagWriterState.WritePosition, logRecord.Body.AsSpan());
-            }
         }
 
         if (logRecord.TraceId != default && logRecord.SpanId != default)

src/OpenTelemetry/Logs/LoggerSdk.cs

@@ -39,6 +39,7 @@ public override void EmitLog(in LogRecordData data, in LogRecordAttributeList at
             logRecord.Logger = this;
 
             logRecord.AttributeData = attributes.Export(ref logRecord.AttributeStorage);
+            logRecord.FormattedMessage = logRecord.Body;
 
             processor.OnEnd(logRecord);
 

test/OpenTelemetry.Exporter.OpenTelemetryProtocol.Tests/OtlpLogExporterTests.cs

@@ -610,6 +610,55 @@ public void LogRecordBodyIsExportedWhenUsingBridgeApi(bool isBodySet)
         Assert.Equal("Hello from {name} {price}.", otlpLogRecord.Body.StringValue);
     }
 
+    [Fact]
+    public void LogRecordBodyAndOriginalFormatIsExportedWhenUsingBridgeApi()
+    {
+        LogRecordAttributeList attributes = default;
+        attributes.Add("name", "tomato");
+        attributes.Add("price", 2.99);
+        attributes.Add("{OriginalFormat}", "Hello from {name} {price}.");
+
+        var logRecords = new List<LogRecord>();
+
+        using (var loggerProvider = Sdk.CreateLoggerProviderBuilder()
+                   .AddInMemoryExporter(logRecords)
+                   .Build())
+        {
+            var logger = loggerProvider.GetLogger();
+
+            logger.EmitLog(
+                new LogRecordData()
+            {
+                Body = "Hello world",
+            },
+                attributes);
+        }
+
+        Assert.Single(logRecords);
+
+        var otlpLogRecord = ToOtlpLogs(DefaultSdkLimitOptions, new ExperimentalOptions(), logRecords[0]);
+
+        Assert.NotNull(otlpLogRecord);
+
+        Assert.Equal("Hello world", otlpLogRecord.Body?.StringValue);
+
+        Assert.NotNull(otlpLogRecord);
+        Assert.Equal(3, otlpLogRecord.Attributes.Count);
+
+        var index = 0;
+        var attribute = otlpLogRecord.Attributes[index];
+        Assert.Equal("name", attribute.Key);
+        Assert.Equal("tomato", attribute.Value.StringValue);
+
+        attribute = otlpLogRecord.Attributes[++index];
+        Assert.Equal("price", attribute.Key);
+        Assert.Equal(2.99, attribute.Value.DoubleValue);
+
+        attribute = otlpLogRecord.Attributes[++index];
+        Assert.Equal("{OriginalFormat}", attribute.Key);
+        Assert.Equal("Hello from {name} {price}.", attribute.Value.StringValue);
+    }
+
     [Fact]
     public void CheckToOtlpLogRecordExceptionAttributes()
     {