avoid error on 5.6 when sendable convertible used

Author: ktoso

Sources/Tracing/Span.swift

@@ -392,11 +392,18 @@ extension Array: SpanAttributeConvertible where Element: SpanAttributeConvertibl
             return .boolArray(value)
         } else if let value = self as? [String] {
             return .stringArray(value)
-        } else if let value = self as? [CustomStringConvertible] {
+        }
+        #if swift(>=5.6.0)
+        if let value = self as? [CustomStringConvertible & Sendable] {
+            return .stringConvertibleArray(value)
+        }
+        #else
+        if let value = self as? [CustomStringConvertible] {
             return .stringConvertibleArray(value)
-        } else {
-            fatalError("Not supported SpanAttribute array type: \(type(of: self))")
         }
+        #endif
+
+        fatalError("Not supported SpanAttribute array type: \(type(of: self))")
     }
 }
 

Tests/TracingTests/SpanTests.swift

@@ -244,7 +244,7 @@ public struct HTTPAttributes: SpanAttributeNamespace {
     }
 }
 
-public struct CustomAttributeValue: Equatable, CustomStringConvertible, SpanAttributeConvertible {
+public struct CustomAttributeValue: Equatable, _CustomAttributeValueSendable, CustomStringConvertible, SpanAttributeConvertible {
     public func toSpanAttribute() -> SpanAttribute {
         .stringConvertible(self)
     }
@@ -255,6 +255,12 @@ public struct CustomAttributeValue: Equatable, CustomStringConvertible, SpanAttr
 }
 #endif
 
+#if swift(>=5.6.0)
+typealias _CustomAttributeValueSendable = Sendable
+#else
+typealias _CustomAttributeValueSendable = Any
+#endif
+
 private struct TestBaggageContextKey: BaggageKey {
     typealias Value = String
 }