From d02175632aef15a739d5289ca994cab0ca0f0581 Mon Sep 17 00:00:00 2001
From: Giovanni Liva <giovanni.liva@dynatrace.com>
Date: Wed, 28 Apr 2021 14:21:26 +0200
Subject: [PATCH] Fix  ParentBasedSampler

---
 .../src/trace/sampler/ParentBasedSampler.ts   |  3 +-
 .../test/trace/ParentBasedSampler.test.ts     | 36 +++++++++++++++++++
 2 files changed, 38 insertions(+), 1 deletion(-)

diff --git a/packages/opentelemetry-core/src/trace/sampler/ParentBasedSampler.ts b/packages/opentelemetry-core/src/trace/sampler/ParentBasedSampler.ts
index 4cd5c4f871..a20f9ba181 100644
--- a/packages/opentelemetry-core/src/trace/sampler/ParentBasedSampler.ts
+++ b/packages/opentelemetry-core/src/trace/sampler/ParentBasedSampler.ts
@@ -18,6 +18,7 @@ import {
   SpanAttributes,
   Context,
   getSpanContext,
+  isSpanContextValid,
   Link,
   Sampler,
   SamplingResult,
@@ -69,7 +70,7 @@ export class ParentBasedSampler implements Sampler {
   ): SamplingResult {
     const parentContext = getSpanContext(context);
 
-    if (!parentContext) {
+    if (!parentContext || !isSpanContextValid(parentContext)) {
       return this._root.shouldSample(
         context,
         traceId,
diff --git a/packages/opentelemetry-core/test/trace/ParentBasedSampler.test.ts b/packages/opentelemetry-core/test/trace/ParentBasedSampler.test.ts
index e6c388ebe7..4394227de4 100644
--- a/packages/opentelemetry-core/test/trace/ParentBasedSampler.test.ts
+++ b/packages/opentelemetry-core/test/trace/ParentBasedSampler.test.ts
@@ -71,6 +71,24 @@ describe('ParentBasedSampler', () => {
     );
   });
 
+  it('should return api.SamplingDecision.RECORD_AND_SAMPLED for invalid parent spanContext while composited with AlwaysOnSampler', () => {
+    const sampler = new ParentBasedSampler({ root: new AlwaysOnSampler() });
+
+    assert.deepStrictEqual(
+      sampler.shouldSample(
+        setSpanContext(api.ROOT_CONTEXT, api.INVALID_SPAN_CONTEXT),
+        traceId,
+        spanName,
+        SpanKind.CLIENT,
+        {},
+        []
+      ),
+      {
+        decision: api.SamplingDecision.RECORD_AND_SAMPLED,
+      }
+    );
+  });
+
   it('should return api.SamplingDecision.RECORD_AND_SAMPLED while composited with AlwaysOnSampler', () => {
     const sampler = new ParentBasedSampler({ root: new AlwaysOnSampler() });
 
@@ -112,6 +130,24 @@ describe('ParentBasedSampler', () => {
     );
   });
 
+  it('should return api.SamplingDecision.NOT_RECORD for invalid parent spanContext while composited with AlwaysOffSampler', () => {
+    const sampler = new ParentBasedSampler({ root: new AlwaysOffSampler() });
+
+    assert.deepStrictEqual(
+      sampler.shouldSample(
+        setSpanContext(api.ROOT_CONTEXT, api.INVALID_SPAN_CONTEXT),
+        traceId,
+        spanName,
+        SpanKind.CLIENT,
+        {},
+        []
+      ),
+      {
+        decision: api.SamplingDecision.NOT_RECORD,
+      }
+    );
+  });
+
   it('should return api.SamplingDecision.RECORD_AND_SAMPLED while composited with AlwaysOffSampler', () => {
     const sampler = new ParentBasedSampler({ root: new AlwaysOffSampler() });