From 1e643a8221f9a7b4a5fe93b04ad3fc3cfa2ba50e Mon Sep 17 00:00:00 2001
From: Daniel Dyla <dyladan@users.noreply.github.com>
Date: Fri, 27 Mar 2020 09:17:17 -0400
Subject: [PATCH] fix: add type checking in propagators (#904)

---
 src/JaegerHttpTracePropagator.ts       |  3 ++-
 test/JaegerHttpTracePropagator.test.ts | 22 ++++++++++++++++++++++
 2 files changed, 24 insertions(+), 1 deletion(-)

diff --git a/src/JaegerHttpTracePropagator.ts b/src/JaegerHttpTracePropagator.ts
index 13901fc8a1e..a5ab840dc7f 100644
--- a/src/JaegerHttpTracePropagator.ts
+++ b/src/JaegerHttpTracePropagator.ts
@@ -71,11 +71,12 @@ export class JaegerHttpTracePropagator implements HttpTextPropagator {
 
   extract(context: Context, carrier: unknown, getter: GetterFunction): Context {
     const uberTraceIdHeader = getter(carrier, this._jaegerTraceHeader);
-    if (!uberTraceIdHeader) return context;
     const uberTraceId = Array.isArray(uberTraceIdHeader)
       ? uberTraceIdHeader[0]
       : uberTraceIdHeader;
 
+    if (typeof uberTraceId !== 'string') return context;
+
     const spanContext = deserializeSpanContext(uberTraceId);
     if (!spanContext) return context;
 
diff --git a/test/JaegerHttpTracePropagator.test.ts b/test/JaegerHttpTracePropagator.test.ts
index d2fa0b95e89..4013e4e8cd7 100644
--- a/test/JaegerHttpTracePropagator.test.ts
+++ b/test/JaegerHttpTracePropagator.test.ts
@@ -185,4 +185,26 @@ describe('JaegerHttpTracePropagator', () => {
       );
     });
   });
+
+  it('should fail gracefully on bad responses from getter', () => {
+    const ctx1 = jaegerHttpTracePropagator.extract(
+      Context.ROOT_CONTEXT,
+      carrier,
+      (c, k) => 1 // not a number
+    );
+    const ctx2 = jaegerHttpTracePropagator.extract(
+      Context.ROOT_CONTEXT,
+      carrier,
+      (c, k) => [] // empty array
+    );
+    const ctx3 = jaegerHttpTracePropagator.extract(
+      Context.ROOT_CONTEXT,
+      carrier,
+      (c, k) => undefined // missing value
+    );
+
+    assert.ok(ctx1 === Context.ROOT_CONTEXT);
+    assert.ok(ctx2 === Context.ROOT_CONTEXT);
+    assert.ok(ctx3 === Context.ROOT_CONTEXT);
+  });
 });