skip extra processor when disabled

Author: SylvainJuge

span-stacktrace/src/main/java/io/opentelemetry/contrib/stacktrace/StackTraceAutoConfig.java

@@ -34,8 +34,10 @@ public void customize(AutoConfigurationCustomizer config) {
     config.addTracerProviderCustomizer(
         (providerBuilder, properties) -> {
           long minDuration = getMinDuration(properties);
-          Predicate<ReadableSpan> filter = getFilterPredicate(properties);
-          providerBuilder.addSpanProcessor(new StackTraceSpanProcessor(minDuration, filter));
+          if (minDuration >= 0) {
+            Predicate<ReadableSpan> filter = getFilterPredicate(properties);
+            providerBuilder.addSpanProcessor(new StackTraceSpanProcessor(minDuration, filter));
+          }
           return providerBuilder;
         });
   }

span-stacktrace/src/main/java/io/opentelemetry/contrib/stacktrace/StackTraceSpanProcessor.java

@@ -30,6 +30,10 @@ public class StackTraceSpanProcessor implements ExtendedSpanProcessor {
    */
   public StackTraceSpanProcessor(
       long minSpanDurationNanos, Predicate<ReadableSpan> filterPredicate) {
+    if (minSpanDurationNanos < 0) {
+      throw new IllegalArgumentException("minimal span duration must be positive or zero");
+    }
+
     this.minSpanDurationNanos = minSpanDurationNanos;
     this.filterPredicate = filterPredicate;
   }