fix: traceparent's trace-flags are mandatory

Author: hangy

src/Sentry.AspNetCore/Extensions/HttpContextExtensions.cs

@@ -63,7 +63,7 @@ internal static class HttpContextExtensions
             options?.LogError(ex, "Invalid Sentry trace header '{0}'.", value);
             return null;
         }
-    }    
+    }
 
     public static W3CTraceHeader? TryGetW3CTraceHeader(this HttpContext context, SentryOptions? options)
     {

src/Sentry/W3CTraceHeader.cs

@@ -36,7 +36,7 @@ public W3CTraceHeader(SentryTraceHeader source)
     /// </value>
     public SentryTraceHeader SentryTraceHeader { get; }
 
-     /// <summary>
+    /// <summary>
     /// Parses a <see cref="SentryTraceHeader"/> from a string representation of the Sentry trace header.
     /// </summary>
     /// <param name="value">
@@ -57,7 +57,7 @@ public W3CTraceHeader(SentryTraceHeader source)
         }
 
         var components = value.Split('-', StringSplitOptions.RemoveEmptyEntries);
-        if (components.Length < 2)
+        if (components.Length < 4)
         {
             throw new FormatException($"Invalid W3C trace header: {value}.");
         }
@@ -71,9 +71,7 @@ public W3CTraceHeader(SentryTraceHeader source)
         var traceId = SentryId.Parse(components[1]);
         var spanId = SpanId.Parse(components[2]);
 
-        var isSampled = components.Length >= 4
-            ? string.Equals(components[3], "01", StringComparison.OrdinalIgnoreCase)
-            : (bool?)null;
+        var isSampled = string.Equals(components[3], "01", StringComparison.OrdinalIgnoreCase);
 
         return new W3CTraceHeader(new SentryTraceHeader(traceId, spanId, isSampled));
     }
@@ -82,11 +80,6 @@ public W3CTraceHeader(SentryTraceHeader source)
     public override string ToString()
     {
         var traceFlags = ConvertSampledToTraceFlags(SentryTraceHeader.IsSampled);
-        if (traceFlags is null)
-        {
-            return $"{SupportedVersion}-{SentryTraceHeader.TraceId}-{SentryTraceHeader.SpanId}";
-        }
-
         return $"{SupportedVersion}-{SentryTraceHeader.TraceId}-{SentryTraceHeader.SpanId}-{traceFlags}";
     }
 
@@ -104,13 +97,5 @@ public override bool Equals(object? obj)
     /// <inheritdoc/>
     public override int GetHashCode() => SentryTraceHeader.GetHashCode();
 
-    private static string? ConvertSampledToTraceFlags(bool? isSampled)
-    {
-        return isSampled switch
-        {
-            true => "01",
-            false => "00",
-            null => null
-        };
-    }
+    private static string? ConvertSampledToTraceFlags(bool? isSampled) => isSampled ?? false ? "01" : "00";
 }

test/Sentry.Tests/W3CTraceHeaderTests.cs

@@ -29,6 +29,6 @@ public void ToString_WithoutSampled_ConvertsToW3CFormat()
         var result = traceHeader.ToString();
 
         // Assert
-        result.Should().Be("00-75302ac48a024bde9a3b3734a82e36c8-1000000000000000");
+        result.Should().Be("00-75302ac48a024bde9a3b3734a82e36c8-1000000000000000-00");
     }
 }