ref(core): Ensure non-sampled spans are NonRecordingSpans

Author: mydea

packages/core/src/tracing/idleSpan.ts

@@ -15,6 +15,7 @@ import {
   spanToJSON,
 } from '../utils/spanUtils';
 import { SentryNonRecordingSpan } from './sentryNonRecordingSpan';
+import { recordDroppedRootSpan } from './sentrySpan';
 import { SPAN_STATUS_ERROR } from './spanstatus';
 import { startInactiveSpan } from './trace';
 
@@ -124,6 +125,14 @@ export function startIdleSpan(startSpanOptions: StartSpanOptions, options: Parti
         beforeSpanEnd(span);
       }
 
+      // If the span is non-recording, nothing more to do here...
+      // This is the case if tracing is enabled but this specific span was not sampled
+      // We make sure to record this as dropped in this case
+      if (thisArg instanceof SentryNonRecordingSpan) {
+        recordDroppedRootSpan(thisArg);
+        return;
+      }
+
       // Just ensuring that this keeps working, even if we ever have more arguments here
       const [definedEndTimestamp, ...rest] = args;
       const timestamp = definedEndTimestamp || timestampInSeconds();

packages/core/src/tracing/sentrySpan.ts

@@ -34,6 +34,7 @@ import {
   getRootSpan,
   getSpanDescendants,
   getStatusMessage,
+  spanIsSampled,
   spanTimeInputToSeconds,
   spanToJSON,
   spanToTransactionTraceContext,
@@ -333,17 +334,9 @@ export class SentrySpan implements Span {
     }
 
     const { scope: capturedSpanScope, isolationScope: capturedSpanIsolationScope } = getCapturedScopesOnSpan(this);
-    const scope = capturedSpanScope || getCurrentScope();
-    const client = scope.getClient() || getClient();
 
     if (this._sampled !== true) {
-      // At this point if `sampled !== true` we want to discard the transaction.
-      DEBUG_BUILD && logger.log('[Tracing] Discarding transaction because its trace was not chosen to be sampled.');
-
-      if (client) {
-        client.recordDroppedEvent('sample_rate', 'transaction');
-      }
-
+      recordDroppedRootSpan(this);
       return undefined;
     }
 
@@ -442,3 +435,18 @@ function sendSpanEnvelope(envelope: SpanEnvelope): void {
   // eslint-disable-next-line @typescript-eslint/no-floating-promises
   client.sendEnvelope(envelope);
 }
+
+/** Record a dropped root span. */
+export function recordDroppedRootSpan(span: Span): void {
+  const { scope: capturedSpanScope } = getCapturedScopesOnSpan(span);
+  const scope = capturedSpanScope || getCurrentScope();
+  const client = scope.getClient() || getClient();
+
+  if (!spanIsSampled(span)) {
+    DEBUG_BUILD && logger.log('[Tracing] Discarding root span because its trace was not chosen to be sampled.');
+
+    if (client) {
+      client.recordDroppedEvent('sample_rate', 'transaction');
+    }
+  }
+}

packages/core/src/tracing/trace.ts

@@ -370,9 +370,13 @@ function getAcs(): AsyncContextStrategy {
   return getAsyncContextStrategy(carrier);
 }
 
-function _startRootSpan(spanArguments: SentrySpanArguments, scope: Scope, parentSampled?: boolean): SentrySpan {
+function _startRootSpan(
+  spanArguments: SentrySpanArguments,
+  scope: Scope,
+  parentSampled?: boolean,
+): SentrySpan | SentryNonRecordingSpan {
   const client = getClient();
-  const options: Partial<ClientOptions> = (client && client.getOptions()) || {};
+  const options: Partial<ClientOptions> = client?.getOptions() || {};
 
   const { name = '', attributes } = spanArguments;
   const [sampled, sampleRate] = scope.getScopeData().sdkProcessingMetadata[SUPPRESS_TRACING_KEY]
@@ -387,14 +391,17 @@ function _startRootSpan(spanArguments: SentrySpanArguments, scope: Scope, parent
         },
       });
 
-  const rootSpan = new SentrySpan({
-    ...spanArguments,
-    attributes: {
-      [SEMANTIC_ATTRIBUTE_SENTRY_SOURCE]: 'custom',
-      ...spanArguments.attributes,
-    },
-    sampled,
-  });
+  const rootSpan = sampled
+    ? new SentrySpan({
+        ...spanArguments,
+        attributes: {
+          [SEMANTIC_ATTRIBUTE_SENTRY_SOURCE]: 'custom',
+          ...spanArguments.attributes,
+        },
+        sampled,
+      })
+    : new SentryNonRecordingSpan({ traceId: spanArguments.traceId });
+
   if (sampleRate !== undefined) {
     rootSpan.setAttribute(SEMANTIC_ATTRIBUTE_SENTRY_SAMPLE_RATE, sampleRate);
   }