From 8dae68df8feb7f649799a4e1d87029211567bbeb Mon Sep 17 00:00:00 2001
From: Neal Beeken <neal.beeken@mongodb.com>
Date: Wed, 12 Apr 2023 16:02:32 -0400
Subject: [PATCH] fix: assumption about Bun typeof

---
 src/cmap/handshake/client_metadata.ts            |  5 ++++-
 test/unit/cmap/handshake/client_metadata.test.ts | 12 +++++++++++-
 2 files changed, 15 insertions(+), 2 deletions(-)

diff --git a/src/cmap/handshake/client_metadata.ts b/src/cmap/handshake/client_metadata.ts
index 3aab82c3d6..6a07e73a3f 100644
--- a/src/cmap/handshake/client_metadata.ts
+++ b/src/cmap/handshake/client_metadata.ts
@@ -277,7 +277,10 @@ function getRuntimeInfo(): string {
 
   if ('Bun' in globalThis) {
     const version =
-      Bun != null && typeof Bun === 'object' && 'version' in Bun && typeof Bun.version === 'string'
+      Bun != null &&
+      (typeof Bun === 'function' || typeof Bun === 'object') &&
+      'version' in Bun &&
+      typeof Bun.version === 'string'
         ? Bun.version
         : '0.0.0';
 
diff --git a/test/unit/cmap/handshake/client_metadata.test.ts b/test/unit/cmap/handshake/client_metadata.test.ts
index 31694a7adc..d94700af1c 100644
--- a/test/unit/cmap/handshake/client_metadata.test.ts
+++ b/test/unit/cmap/handshake/client_metadata.test.ts
@@ -344,12 +344,22 @@ describe('client metadata module', () => {
           expect(delete globalThis.Bun, 'failed to delete Bun global').to.be.true;
         });
 
-        it('sets platform to Bun', () => {
+        it('sets platform to Bun if typeof is object', () => {
           globalThis.Bun = { version: '1.2.3' };
           const metadata = makeClientMetadata({ driverInfo: {} });
           expect(metadata.platform).to.equal('Bun v1.2.3, LE');
         });
 
+        it('sets platform to Bun if typeof is function', () => {
+          function Bun() {
+            return null;
+          }
+          Bun.version = '1.2.3';
+          globalThis.Bun = Bun;
+          const metadata = makeClientMetadata({ driverInfo: {} });
+          expect(metadata.platform).to.equal('Bun v1.2.3, LE');
+        });
+
         it('sets platform to Bun with driverInfo.platform', () => {
           globalThis.Bun = { version: '1.2.3' };
           const metadata = makeClientMetadata({ driverInfo: { platform: 'myPlatform' } });