From 777c473a9d4f4240992fb47282c40ac1834e0784 Mon Sep 17 00:00:00 2001
From: Sean Dearnaley <seandearnaley@outlook.com>
Date: Sun, 30 Aug 2026 21:12:49 -0400
Subject: [PATCH] fix: finish spans when decorated methods throw

---
 src/decorator.injector.spec.ts | 28 ++++++++++++++--------------
 src/decorator.injector.ts      |  4 +++-
 2 files changed, 17 insertions(+), 15 deletions(-)

diff --git a/src/decorator.injector.spec.ts b/src/decorator.injector.spec.ts
index 098999d..260003f 100644
--- a/src/decorator.injector.spec.ts
+++ b/src/decorator.injector.spec.ts
@@ -186,13 +186,15 @@ describe('DecoratorInjector', () => {
     scopeSpy.mockClear();
   });
 
-  it('should record exception with sync function', async () => {
+  it('should record and finish a span when a sync function throws', async () => {
     // given
+    const error = new Error('hello');
+
     @Injectable()
     class HelloService {
       @Span('hello')
       hi() {
-        throw new Error('hello');
+        throw error;
       }
     }
 
@@ -220,9 +222,7 @@ describe('DecoratorInjector', () => {
       .mockImplementation(() => scope);
 
     // when
-    expect(() => {
-      helloService.hi();
-    }).toThrowError('hello');
+    expect(() => helloService.hi()).toThrow(error);
 
     // then
     expect(
@@ -237,22 +237,22 @@ describe('DecoratorInjector', () => {
     expect(tracer.startSpan).toHaveBeenCalledWith('hello', { childOf: null });
     expect(tracer.scope().active).toHaveBeenCalled();
     expect(tracer.scope().activate).toHaveBeenCalled();
-    expect(mockSpan.finish).toHaveBeenCalled();
-    expect(mockSpan.setTag).toHaveBeenCalledWith('error', new Error('hello'));
+    expect(mockSpan.setTag).toHaveBeenCalledWith('error', error);
+    expect(mockSpan.finish).toHaveBeenCalledTimes(1);
 
     startSpanSpy.mockClear();
     scopeSpy.mockClear();
   });
 
-  it('should record exception with async function', async () => {
+  it('should record and finish a span when an async function rejects', async () => {
     // given
+    const error = new Error('hello');
+
     @Injectable()
     class HelloService {
       @Span('hello')
       async hi() {
-        return new Promise((_resolve, reject) => {
-          setTimeout(() => reject(new Error('hello')), 100);
-        });
+        throw error;
       }
     }
 
@@ -280,7 +280,7 @@ describe('DecoratorInjector', () => {
       .mockImplementation(() => scope);
 
     // when
-    await expect(helloService.hi()).rejects.toEqual(new Error('hello'));
+    await expect(helloService.hi()).rejects.toBe(error);
 
     // then
     expect(
@@ -295,8 +295,8 @@ describe('DecoratorInjector', () => {
     expect(tracer.startSpan).toHaveBeenCalledWith('hello', { childOf: null });
     expect(tracer.scope().active).toHaveBeenCalled();
     expect(tracer.scope().activate).toHaveBeenCalled();
-    expect(mockSpan.finish).toHaveBeenCalled();
-    expect(mockSpan.setTag).toHaveBeenCalledWith('error', new Error('hello'));
+    expect(mockSpan.setTag).toHaveBeenCalledWith('error', error);
+    expect(mockSpan.finish).toHaveBeenCalledTimes(1);
 
     startSpanSpy.mockClear();
     scopeSpy.mockClear();
diff --git a/src/decorator.injector.ts b/src/decorator.injector.ts
index 3173485..473f76e 100644
--- a/src/decorator.injector.ts
+++ b/src/decorator.injector.ts
@@ -69,7 +69,6 @@ export class DecoratorInjector implements Injector {
    */
   private static recordException(error, span: Span) {
     span.setTag('error', error);
-    throw error;
   }
 
   /**
@@ -185,6 +184,7 @@ export class DecoratorInjector implements Injector {
               .apply(this, args)
               .catch((error) => {
                 DecoratorInjector.recordException(error, span);
+                throw error;
               })
               .finally(() => span.finish());
           } else {
@@ -195,6 +195,7 @@ export class DecoratorInjector implements Injector {
                 return result
                   .catch((error) => {
                     DecoratorInjector.recordException(error, span);
+                    throw error;
                   })
                   .finally(() => span.finish());
               }
@@ -204,6 +205,7 @@ export class DecoratorInjector implements Injector {
             } catch (error) {
               DecoratorInjector.recordException(error, span);
               span.finish();
+              throw error;
             }
           }
         });