ref(core): Ensure non-recording root spans have frozen DSC

Otherwise, parts of the DSC will be missing - we try to make it as complete as we can.

Author: mydea

packages/core/src/tracing/idleSpan.ts

@@ -1,5 +1,5 @@
 import { getClient, getCurrentScope } from '../currentScopes';
-import type { Span, StartSpanOptions } from '../types-hoist';
+import type { DynamicSamplingContext, Span, StartSpanOptions } from '../types-hoist';
 
 import { DEBUG_BUILD } from '../debug-build';
 import { SEMANTIC_ATTRIBUTE_SENTRY_IDLE_SPAN_FINISH_REASON } from '../semanticAttributes';
@@ -14,6 +14,7 @@ import {
   spanTimeInputToSeconds,
   spanToJSON,
 } from '../utils/spanUtils';
+import { freezeDscOnSpan, getDynamicSamplingContextFromSpan } from './dynamicSamplingContext';
 import { SentryNonRecordingSpan } from './sentryNonRecordingSpan';
 import { SPAN_STATUS_ERROR } from './spanstatus';
 import { startInactiveSpan } from './trace';
@@ -109,7 +110,16 @@ export function startIdleSpan(startSpanOptions: StartSpanOptions, options: Parti
   const client = getClient();
 
   if (!client || !hasTracingEnabled()) {
-    return new SentryNonRecordingSpan();
+    const span = new SentryNonRecordingSpan();
+
+    const dsc = {
+      sample_rate: '0',
+      sampled: 'false',
+      ...getDynamicSamplingContextFromSpan(span),
+    } satisfies Partial<DynamicSamplingContext>;
+    freezeDscOnSpan(span, dsc);
+
+    return span;
   }
 
   const scope = getCurrentScope();

packages/core/src/tracing/trace.ts

@@ -2,7 +2,14 @@
 
 import type { AsyncContextStrategy } from '../asyncContext/types';
 import { getMainCarrier } from '../carrier';
-import type { ClientOptions, SentrySpanArguments, Span, SpanTimeInput, StartSpanOptions } from '../types-hoist';
+import type {
+  ClientOptions,
+  DynamicSamplingContext,
+  SentrySpanArguments,
+  Span,
+  SpanTimeInput,
+  StartSpanOptions,
+} from '../types-hoist';
 
 import { getClient, getCurrentScope, getIsolationScope, withScope } from '../currentScopes';
 
@@ -284,7 +291,21 @@ function createChildOrRootSpan({
   scope: Scope;
 }): Span {
   if (!hasTracingEnabled()) {
-    return new SentryNonRecordingSpan();
+    const span = new SentryNonRecordingSpan();
+
+    // If this is a root span, we ensure to freeze a DSC
+    // So we can have at least partial data here
+    if (forceTransaction || !parentSpan) {
+      const dsc = {
+        sampled: 'false',
+        sample_rate: '0',
+        transaction: spanArguments.name,
+        ...getDynamicSamplingContextFromSpan(span),
+      } satisfies Partial<DynamicSamplingContext>;
+      freezeDscOnSpan(span, dsc);
+    }
+
+    return span;
   }
 
   const isolationScope = getIsolationScope();

packages/core/test/lib/tracing/idleSpan.test.ts

@@ -7,6 +7,7 @@ import {
   getActiveSpan,
   getClient,
   getCurrentScope,
+  getDynamicSamplingContextFromSpan,
   getGlobalScope,
   getIsolationScope,
   setCurrentClient,
@@ -60,6 +61,14 @@ describe('startIdleSpan', () => {
     const idleSpan = startIdleSpan({ name: 'foo' });
     expect(idleSpan).toBeDefined();
     expect(idleSpan).toBeInstanceOf(SentryNonRecordingSpan);
+    // DSC is still correctly set on the span
+    expect(getDynamicSamplingContextFromSpan(idleSpan)).toEqual({
+      environment: 'production',
+      public_key: '123',
+      sample_rate: '0',
+      sampled: 'false',
+      trace_id: expect.stringMatching(/[a-f0-9]{32}/),
+    });
 
     // not set as active span, though
     expect(getActiveSpan()).toBe(undefined);

packages/core/test/lib/tracing/trace.test.ts

@@ -15,6 +15,7 @@ import { getAsyncContextStrategy } from '../../../src/asyncContext';
 import {
   SentrySpan,
   continueTrace,
+  getDynamicSamplingContextFromSpan,
   registerSpanErrorInstrumentation,
   startInactiveSpan,
   startSpan,
@@ -217,6 +218,13 @@ describe('startSpan', () => {
 
     expect(span).toBeDefined();
     expect(span).toBeInstanceOf(SentryNonRecordingSpan);
+    expect(getDynamicSamplingContextFromSpan(span)).toEqual({
+      environment: 'production',
+      sample_rate: '0',
+      sampled: 'false',
+      trace_id: expect.stringMatching(/[a-f0-9]{32}/),
+      transaction: 'GET users/[id]',
+    });
   });
 
   it('creates & finishes span', async () => {
@@ -633,6 +641,13 @@ describe('startSpanManual', () => {
 
     expect(span).toBeDefined();
     expect(span).toBeInstanceOf(SentryNonRecordingSpan);
+    expect(getDynamicSamplingContextFromSpan(span)).toEqual({
+      environment: 'production',
+      sample_rate: '0',
+      sampled: 'false',
+      trace_id: expect.stringMatching(/[a-f0-9]{32}/),
+      transaction: 'GET users/[id]',
+    });
   });
 
   it('creates & finishes span', async () => {
@@ -971,6 +986,13 @@ describe('startInactiveSpan', () => {
 
     expect(span).toBeDefined();
     expect(span).toBeInstanceOf(SentryNonRecordingSpan);
+    expect(getDynamicSamplingContextFromSpan(span)).toEqual({
+      environment: 'production',
+      sample_rate: '0',
+      sampled: 'false',
+      trace_id: expect.stringMatching(/[a-f0-9]{32}/),
+      transaction: 'GET users/[id]',
+    });
   });
 
   it('creates & finishes span', async () => {