From fcd1cd6abc4ad73699f8719e0c82fcc992b7de52 Mon Sep 17 00:00:00 2001
From: Amir Blum <amirgiraffe@gmail.com>
Date: Thu, 14 May 2020 16:24:34 +0300
Subject: [PATCH] fix(http-plugin): dont modify user's headers object in plugin

---
 packages/opentelemetry-plugin-http/src/http.ts                  | 2 ++
 .../test/functionals/http-enable.test.ts                        | 1 +
 2 files changed, 3 insertions(+)

diff --git a/packages/opentelemetry-plugin-http/src/http.ts b/packages/opentelemetry-plugin-http/src/http.ts
index 3697ba492ce..481970e4eaf 100644
--- a/packages/opentelemetry-plugin-http/src/http.ts
+++ b/packages/opentelemetry-plugin-http/src/http.ts
@@ -406,6 +406,8 @@ export class HttpPlugin extends BasePlugin<Http> {
       );
 
       if (utils.isOpenTelemetryRequest(optionsParsed)) {
+        // clone the headers so delete will not modify the user's object
+        optionsParsed.headers = Object.assign({}, optionsParsed.headers);
         delete optionsParsed.headers[utils.OT_REQUEST_HEADER];
         return original.apply(this, [optionsParsed, ...args]);
       }
diff --git a/packages/opentelemetry-plugin-http/test/functionals/http-enable.test.ts b/packages/opentelemetry-plugin-http/test/functionals/http-enable.test.ts
index 51400d239cf..812194e4230 100644
--- a/packages/opentelemetry-plugin-http/test/functionals/http-enable.test.ts
+++ b/packages/opentelemetry-plugin-http/test/functionals/http-enable.test.ts
@@ -202,6 +202,7 @@ describe('HttpPlugin', () => {
         const spans = memoryExporter.getFinishedSpans();
         assert.strictEqual(result.data, 'Ok');
         assert.strictEqual(spans.length, 0);
+        assert.strictEqual(options.headers[OT_REQUEST_HEADER], 1);
       });
     });
     describe('with good plugin options', () => {