fix: exception.type should always be a string (#2086)

Author: YanivD

packages/opentelemetry-tracing/src/Span.ts

@@ -193,7 +193,7 @@ export class Span implements api.Span, ReadableSpan {
       attributes[ExceptionAttribute.MESSAGE] = exception;
     } else if (exception) {
       if (exception.code) {
-        attributes[ExceptionAttribute.TYPE] = exception.code;
+        attributes[ExceptionAttribute.TYPE] = exception.code.toString();
       } else if (exception.name) {
         attributes[ExceptionAttribute.TYPE] = exception.name;
       }

packages/opentelemetry-tracing/test/Span.test.ts

@@ -719,5 +719,23 @@ describe('Span', () => {
         assert.deepStrictEqual(event.time, [0, 123]);
       });
     });
+
+    describe('when exception code is numeric', () => {
+      it('should record an exception with string value', () => {
+        const span = new Span(
+          tracer,
+          ROOT_CONTEXT,
+          name,
+          spanContext,
+          SpanKind.CLIENT
+        );
+        assert.strictEqual(span.events.length, 0);
+        span.recordException({ code: 12 });
+        const event = span.events[0];
+        assert.deepStrictEqual(event.attributes, {
+          [ExceptionAttribute.TYPE]: '12',
+        });
+      });
+    });
   });
 });