[API] Baggage - Trim white spaces and check for semi colon which isn't allowed octet

src/OpenTelemetry.Api/CHANGELOG.md

@@ -17,6 +17,15 @@ Notes](../../RELEASENOTES.md).
   align with the W3C Trace Context specification.
   ([#7065](https://github.com/open-telemetry/opentelemetry-dotnet/pull/7065))
 
+* Fixed `BaggagePropagator` to trim optional whitespace (OWS) around `=`
+  separators when parsing the `baggage` header, as required by the
+  [W3C Baggage specification](https://www.w3.org/TR/baggage/).
+  ([#7009](https://github.com/open-telemetry/opentelemetry-dotnet/pull/7009))
+
+* Fixed `BaggagePropagator` to strip baggage properties (e.g. `;metadata`)
+  from values when parsing the `baggage` header.
+  ([#7009](https://github.com/open-telemetry/opentelemetry-dotnet/pull/7009))
+
 ## 1.15.2
 
 Released 2026-Apr-08

src/OpenTelemetry.Api/Context/Propagation/BaggagePropagator.cs

@@ -181,8 +181,20 @@ internal static bool TryExtractBaggage(
                     continue;
                 }
 
-                var key = DecodeIfNeeded(pair.Slice(0, separatorIndex));
-                var value = DecodeIfNeeded(pair.Slice(separatorIndex + 1));
+                var rawKey = pair.Slice(0, separatorIndex).Trim();
+
+                var rawValue = pair.Slice(separatorIndex + 1);
+
+                var semicolonIndex = rawValue.IndexOf(';');
+                if (semicolonIndex >= 0)
+                {
+                    rawValue = rawValue.Slice(0, semicolonIndex);
+                }
+
+                rawValue = rawValue.Trim();
+
+                var key = DecodeIfNeeded(rawKey);
+                var value = DecodeIfNeeded(rawValue);
 
                 if (string.IsNullOrEmpty(key) || string.IsNullOrEmpty(value))
                 {

test/Benchmarks/Context/Propagation/BaggagePropagatorBenchmarks.cs

@@ -26,6 +26,12 @@ public class BaggagePropagatorBenchmarks
     [Params(false, true)]
     public bool UseSpecialChars { get; set; }
 
+    /// <summary>
+    /// Gets or sets the header style used in each benchmark run.
+    /// </summary>
+    [Params("WithOWSAndProperties", "Clean")]
+    public string HeaderStyle { get; set; } = "Clean";
+
     public Dictionary<string, string> ExtractCarrier { get; private set; } = [];
 
     public Dictionary<string, string> InjectCarrier { get; private set; } = [];
@@ -43,8 +49,11 @@ public void Setup()
                     : ($"key{i}", $"value{i}"));
         }
 
-        var baggageHeader = string.Join(",", Items().Select(p =>
-            $"{Uri.EscapeDataString(p.Key)}={Uri.EscapeDataString(p.Value)}"));
+        var baggageHeader = this.HeaderStyle switch
+        {
+            "WithOWSAndProperties" => string.Join(" , ", Items().Select(p => $"{Uri.EscapeDataString(p.Key)} = {Uri.EscapeDataString(p.Value)} ; prop1 ; propKey=propValue")),
+            _ => string.Join(",", Items().Select(p => $"{Uri.EscapeDataString(p.Key)}={Uri.EscapeDataString(p.Value)}")),
+        };
 
         this.ExtractCarrier = new Dictionary<string, string>
         {

test/OpenTelemetry.Api.Tests/Context/Propagation/BaggagePropagatorTests.cs

@@ -227,7 +227,7 @@ public void ValidateEmptyValueSkipped()
         Assert.Empty(propagationContext.Baggage.GetBaggage());
     }
 
-    [Fact(Skip = "Fails due to spec mismatch, tracked in https://github.com/open-telemetry/opentelemetry-dotnet/issues/5210")]
+    [Fact]
     public void ValidateOWSOnExtraction()
     {
         var carrier = new Dictionary<string, string>
@@ -248,7 +248,7 @@ public void ValidateOWSOnExtraction()
         Assert.Equal("SomeValue2", baggage[1].Value);
     }
 
-    [Fact(Skip = "Fails due to spec mismatch, tracked in https://github.com/open-telemetry/opentelemetry-dotnet/issues/5210")]
+    [Fact]
     public void ValidateSemicolonMetadataIgnoredOnExtraction()
     {
         var carrier = new Dictionary<string, string>
@@ -265,6 +265,39 @@ public void ValidateSemicolonMetadataIgnoredOnExtraction()
         Assert.Equal("SomeValue", baggage.Value);
     }
 
+    [Fact]
+    public void ValidateOptionalWhiteSpaceExtractionDoesNotCorruptOnReinjection()
+    {
+        // Simulates a header emitted by .NET 10's W3C propagator
+        var carrier = new Dictionary<string, string>
+        {
+            { BaggagePropagator.BaggageHeaderName, "correlationId = 12345, userId = user-abc" },
+        };
+
+        var extractedContext = this.baggage.Extract(default, carrier, Getter);
+
+        var outboundCarrier = new Dictionary<string, string>();
+        this.baggage.Inject(extractedContext, outboundCarrier, Setter);
+
+        Assert.Equal("correlationId=12345,userId=user-abc", outboundCarrier[BaggagePropagator.BaggageHeaderName]);
+    }
+
+    [Fact]
+    public void ValidateOptionalWhiteSpaceBeforeSemicolonIgnored()
+    {
+        var carrier = new Dictionary<string, string>
+        {
+            { BaggagePropagator.BaggageHeaderName, "SomeKey=SomeValue ; propertyKey=propertyValue" },
+        };
+
+        var propagationContext = this.baggage.Extract(default, carrier, Getter);
+
+        var baggage = Assert.Single(propagationContext.Baggage.GetBaggage());
+
+        Assert.Equal("SomeKey", baggage.Key);
+        Assert.Equal("SomeValue", baggage.Value);
+    }
+
     [Fact]
     public void ValidatePercentEncoding()
     {