Align Baggage API name and value handling to match the v1.36.0 specification

src/OpenTelemetry.Api/Baggage.cs

@@ -94,7 +94,7 @@ public static Baggage Create(Dictionary<string, string>? baggageItems = null)
             return default;
         }
 
-        Dictionary<string, string> baggageCopy = new Dictionary<string, string>(baggageItems.Count, StringComparer.OrdinalIgnoreCase);
+        Dictionary<string, string> baggageCopy = new Dictionary<string, string>(baggageItems.Count, StringComparer.Ordinal);
         foreach (KeyValuePair<string, string> baggageItem in baggageItems)
         {
             if (string.IsNullOrEmpty(baggageItem.Value))
@@ -239,13 +239,18 @@ public IReadOnlyDictionary<string, string> GetBaggage()
     /// <returns>New <see cref="Baggage"/> containing the key/value pair.</returns>
     public Baggage SetBaggage(string name, string? value)
     {
+        if (string.IsNullOrEmpty(name))
+        {
+            return this;
+        }
+
         if (string.IsNullOrEmpty(value))
         {
             return this.RemoveBaggage(name);
         }
 
         return new Baggage(
-            new Dictionary<string, string>(this.baggage ?? EmptyBaggage, StringComparer.OrdinalIgnoreCase)
+            new Dictionary<string, string>(this.baggage ?? EmptyBaggage, StringComparer.Ordinal)
             {
                 [name] = value!,
             });
@@ -271,11 +276,15 @@ public Baggage SetBaggage(IEnumerable<KeyValuePair<string, string?>> baggageItem
             return this;
         }
 
-        var newBaggage = new Dictionary<string, string>(this.baggage ?? EmptyBaggage, StringComparer.OrdinalIgnoreCase);
+        var newBaggage = new Dictionary<string, string>(this.baggage ?? EmptyBaggage, StringComparer.Ordinal);
 
         foreach (var item in baggageItems)
         {
-            if (string.IsNullOrEmpty(item.Value))
+            if (string.IsNullOrEmpty(item.Key))
+            {
+                continue;
+            }
+            else if (string.IsNullOrEmpty(item.Value))
             {
                 newBaggage.Remove(item.Key);
             }
@@ -295,7 +304,7 @@ public Baggage SetBaggage(IEnumerable<KeyValuePair<string, string?>> baggageItem
     /// <returns>New <see cref="Baggage"/> with the key/value pair removed.</returns>
     public Baggage RemoveBaggage(string name)
     {
-        var baggage = new Dictionary<string, string>(this.baggage ?? EmptyBaggage, StringComparer.OrdinalIgnoreCase);
+        var baggage = new Dictionary<string, string>(this.baggage ?? EmptyBaggage, StringComparer.Ordinal);
         baggage.Remove(name);
 
         return new Baggage(baggage);

src/OpenTelemetry.Api/CHANGELOG.md

@@ -6,6 +6,12 @@ Notes](../../RELEASENOTES.md).
 
 ## Unreleased
 
+* **Breaking change:** The Baggage API implements the latest [Baggage API
+  specification](https://github.com/open-telemetry/opentelemetry-specification/blob/v1.36.0/specification/baggage/api.md),
+  which disallows empty baggage names and treats baggage names and values as case
+  sensitive.
+  ([#6931](https://github.com/open-telemetry/opentelemetry-dotnet/pull/6931))
+
 ## 1.15.0
 
 Released 2026-Jan-21

test/OpenTelemetry.Api.Tests/BaggageTests.cs

@@ -26,26 +26,36 @@ public void EmptyTest()
     [Fact]
     public void SetAndGetTest()
     {
-        var list = new List<KeyValuePair<string, string>>(2)
+        var list = new List<KeyValuePair<string, string>>(4)
         {
             new(K1, V1),
-            new(K2, V2),
+            new("key2", "VALUE2"),
+            new("KEY2", "VALUE2"),
+
+            // Encode Unicode characters in Basic Multilingual Plane (U+0000 to U+FFFF)
+            // and in supplementary code points (U+10000 to U+10FFFF)
+            new("key \U000000A9", "value \U0001F600"),
         };
 
         Baggage.SetBaggage(K1, V1);
-        var baggage = Baggage.Current.SetBaggage(K2, V2);
+        var baggage = Baggage.Current.SetBaggage(new KeyValuePair<string, string?>("key2", "value2"));
+        baggage = baggage.SetBaggage(new KeyValuePair<string, string?>("key2", "VALUE2"));
+        baggage = baggage.SetBaggage(new KeyValuePair<string, string?>("KEY2", "VALUE2"));
+        baggage = baggage.SetBaggage("key \U000000A9", "value \U0001F600");
         Baggage.Current = baggage;
 
         Assert.NotEmpty(Baggage.GetBaggage());
         Assert.Equal(list, Baggage.GetBaggage(Baggage.Current));
 
         Assert.Equal(V1, Baggage.GetBaggage(K1));
 #pragma warning disable CA1308 // Normalize strings to uppercase
-        Assert.Equal(V1, Baggage.GetBaggage(K1.ToLower(CultureInfo.InvariantCulture)));
+        Assert.Null(Baggage.GetBaggage(K1.ToLower(CultureInfo.InvariantCulture)));
 #pragma warning restore CA1308 // Normalize strings to uppercase
-        Assert.Equal(V1, Baggage.GetBaggage(K1.ToUpper(CultureInfo.InvariantCulture)));
+        Assert.Null(Baggage.GetBaggage(K1.ToUpper(CultureInfo.InvariantCulture)));
         Assert.Null(Baggage.GetBaggage("NO_KEY"));
-        Assert.Equal(V2, Baggage.Current.GetBaggage(K2));
+        Assert.Equal("VALUE2", Baggage.Current.GetBaggage("key2"));
+        Assert.Equal("VALUE2", Baggage.Current.GetBaggage("KEY2"));
+        Assert.Equal("value \U0001F600", Baggage.Current.GetBaggage("key \U000000A9"));
 
         Assert.Throws<ArgumentException>(() => Baggage.GetBaggage(null!));
     }
@@ -65,6 +75,21 @@ public void SetExistingKeyTest()
         Assert.Equal(list, Baggage.GetBaggage());
     }
 
+    [Fact]
+    public void SetEmptyNameTest()
+    {
+        var baggage = Baggage.Current;
+        baggage = Baggage.SetBaggage(K1, V1, baggage);
+
+        Assert.Equal(1, Baggage.Current.Count);
+        Assert.Equal(1, baggage.Count);
+
+        baggage = Baggage.Current.SetBaggage(string.Empty, "unused-value-1");
+
+        Assert.Equal(1, baggage.Count);
+        Assert.Contains(baggage.GetBaggage(), kvp => kvp.Key == K1);
+    }
+
     [Fact]
     public void SetNullValueTest()
     {
@@ -100,8 +125,8 @@ public void RemoveTest()
         var baggage = Baggage.SetBaggage(new Dictionary<string, string?>
         {
             [K1] = V1,
-            [K2] = V2,
-            [K3] = V3,
+            ["key2"] = "value2",
+            ["KEY2"] = "VALUE2",
         });
 
         var baggage2 = Baggage.RemoveBaggage(K1, baggage);
@@ -133,9 +158,9 @@ public void ClearTest()
     public void ContextFlowTest()
     {
         var baggage = Baggage.SetBaggage(K1, V1);
-        var baggage2 = Baggage.Current.SetBaggage(K2, V2);
+        var baggage2 = Baggage.Current.SetBaggage("key2", "value2");
         Baggage.Current = baggage2;
-        var baggage3 = Baggage.SetBaggage(K3, V3);
+        var baggage3 = Baggage.SetBaggage("KEY2", "VALUE2");
 
         Assert.Equal(1, baggage.Count);
         Assert.Equal(2, baggage2.Count);
@@ -213,9 +238,11 @@ public void CreateBaggageTest()
             ["Key3"] = null!, // Note: This causes Key3 to be removed
         });
 
-        Assert.Equal(2, baggage.Count);
+        Assert.Equal(4, baggage.Count);
         Assert.Contains(baggage.GetBaggage(), kvp => kvp.Key == K1);
-        Assert.Equal("VALUE2", Baggage.GetBaggage("key2", baggage));
+        Assert.Equal("value2", Baggage.GetBaggage("key2", baggage));
+        Assert.Equal("VALUE2", Baggage.GetBaggage("KEY2", baggage));
+        Assert.Equal("VALUE3", Baggage.GetBaggage("KEY3", baggage));
     }
 
     [Fact]