fix: Fixed tracePromise to handle returning result when function being wrapped is not a promise (#46)

Author: bizob2828

lib/transforms.js

@@ -391,8 +391,8 @@ function wrapPromise (state, node) {
         try {
           let promise = __apm$traced();
           if (typeof promise?.then !== 'function') {
-            __apm$ctx.result = result;
-            return result;
+            __apm$ctx.result = promise; 
+            return promise;
           }
           return promise.then(
             result => {

tests/callback_cjs/mod.js

@@ -1,5 +1,7 @@
 function fetch(url, callback) {
-  callback(null, 42);
+  process.nextTick(() => {
+    callback(null, 42);
+  })
 }
 
 module.exports = { fetch };

tests/common/preamble.js

@@ -13,7 +13,7 @@ function getContext (channelName) {
       context.start = true;
     },
     end(message) {
-      message.context.end = true;
+      message.context.end = message.result ?? true
       // Handle end message
     },
     asyncStart(message) {

tests/nested_functions/test.js

@@ -11,6 +11,6 @@ const context = getContext('orchestrion:undici:nested_fn');
   assert.strictEqual(result, 'Hook added');
   assert.deepStrictEqual(context, {
     start: true,
-    end: true,
+    end: 'Hook added' 
   });
 })();

tests/tests.test.mjs

@@ -504,3 +504,15 @@ describe('source_map', () => {
     expect(original.column).toBe(originalReturnColumn)
   })
 })
+
+describe('wrap_promise_non_promise', () => {
+  test('instruments sync function with wrapPromise and properly returns the result via context', () => {
+    runTest('wrap_promise_non_promise', [
+      {
+        channelName: 'fetch_nonpromise',
+        module: { name: TEST_MODULE_NAME, versionRange: '>=0.0.1', filePath: TEST_MODULE_PATH },
+        functionQuery: { functionName: 'fetch', kind: 'Async' }
+      }
+    ])
+  })
+})

tests/wrap_promise_non_promise/mod.js

@@ -0,0 +1,6 @@
+function fetch (url) {
+  return 42;
+}
+
+module.exports = { fetch };
+

tests/wrap_promise_non_promise/test.js

@@ -0,0 +1,10 @@
+const { fetch } = require('./instrumented.js');
+const { assert, getContext } = require('../common/preamble.js');
+const context = getContext('orchestrion:undici:fetch_nonpromise');
+const result = fetch('https://example.com');
+assert.equal(result, 42)
+assert.deepStrictEqual(context, {
+  start: true,
+  end: 42 
+})
+