Validate the span id and trace id when creating the SpanContext (open-telemetry#2728)

And, remove that extra validation from propagators.

Author: jkwatson

api/all/src/main/java/io/opentelemetry/api/trace/ImmutableSpanContext.java

@@ -14,21 +14,30 @@
 abstract class ImmutableSpanContext implements SpanContext {
 
   static final SpanContext INVALID =
-      create(
+      createInternal(
           TraceId.getInvalid(),
           SpanId.getInvalid(),
           TraceFlags.getDefault(),
           TraceState.getDefault(),
           /* remote= */ false);
 
+  private static AutoValue_ImmutableSpanContext createInternal(
+      String traceId, String spanId, TraceFlags traceFlags, TraceState traceState, boolean remote) {
+    return new AutoValue_ImmutableSpanContext(
+        traceId, spanId, traceFlags, traceState, /* remote$= */ remote);
+  }
+
   static SpanContext create(
       String traceIdHex,
       String spanIdHex,
       TraceFlags traceFlags,
       TraceState traceState,
       boolean remote) {
-    return new AutoValue_ImmutableSpanContext(
-        traceIdHex, spanIdHex, traceFlags, traceState, remote);
+    if (SpanId.isValid(spanIdHex) && TraceId.isValid(traceIdHex)) {
+      return createInternal(traceIdHex, spanIdHex, traceFlags, traceState, remote);
+    }
+    return createInternal(
+        TraceId.getInvalid(), SpanId.getInvalid(), traceFlags, traceState, remote);
   }
 
   @Override

api/all/src/main/java/io/opentelemetry/api/trace/propagation/W3CTraceContextPropagator.java

@@ -214,12 +214,10 @@ private static SpanContext extractContextFromTraceParent(String traceparent) {
       String traceId =
           traceparent.substring(TRACE_ID_OFFSET, TRACE_ID_OFFSET + TraceId.getLength());
       String spanId = traceparent.substring(SPAN_ID_OFFSET, SPAN_ID_OFFSET + SpanId.getLength());
-      if (TraceId.isValid(traceId) && SpanId.isValid(spanId)) {
-        TraceFlags traceFlags = TraceFlags.fromHex(traceparent, TRACE_OPTION_OFFSET);
-        return SpanContext.createFromRemoteParent(
-            traceId, spanId, traceFlags, TraceState.getDefault());
-      }
-      return SpanContext.getInvalid();
+
+      TraceFlags traceFlags = TraceFlags.fromHex(traceparent, TRACE_OPTION_OFFSET);
+      return SpanContext.createFromRemoteParent(
+          traceId, spanId, traceFlags, TraceState.getDefault());
     } catch (IllegalArgumentException e) {
       logger.fine("Unparseable traceparent header. Returning INVALID span context.");
       return SpanContext.getInvalid();

extensions/trace-propagators/src/main/java/io/opentelemetry/extension/trace/propagation/AwsXrayPropagator.java

@@ -171,26 +171,6 @@ private static <C> SpanContext getSpanContextFromHeader(C carrier, Getter<C> get
       }
       // TODO: Put the arbitrary TraceHeader keys in OT trace state
     }
-    if (!TraceId.isValid(traceId)) {
-      logger.fine(
-          "Invalid TraceId in X-Ray trace header: '"
-              + TRACE_HEADER_KEY
-              + "' with value "
-              + traceHeader
-              + "'. Returning INVALID span context.");
-      return SpanContext.getInvalid();
-    }
-
-    if (!SpanId.isValid(spanId)) {
-      logger.fine(
-          "Invalid ParentId in X-Ray trace header: '"
-              + TRACE_HEADER_KEY
-              + "' with value "
-              + traceHeader
-              + "'. Returning INVALID span context.");
-      return SpanContext.getInvalid();
-    }
-
     if (isSampled == null) {
       logger.fine(
           "Invalid Sampling flag in X-Ray trace header: '"

extensions/trace-propagators/src/main/java/io/opentelemetry/extension/trace/propagation/JaegerPropagator.java

@@ -240,9 +240,6 @@ private static SpanContext buildSpanContext(String traceId, String spanId, Strin
     try {
       String otelTraceId = StringUtils.padLeft(traceId, MAX_TRACE_ID_LENGTH);
       String otelSpanId = StringUtils.padLeft(spanId, MAX_SPAN_ID_LENGTH);
-      if (!TraceId.isValid(otelTraceId) || !SpanId.isValid(otelSpanId)) {
-        return SpanContext.getInvalid();
-      }
       int flagsInt = Integer.parseInt(flags);
       return SpanContext.createFromRemoteParent(
           otelTraceId,