stop bootstrap buffer as soon as usercode runs

Author: guybedford

lib/internal/async_hooks.js

@@ -289,8 +289,8 @@ function bufferBootstrapHooks() {
   }
 }
 
-function clearBootstrapHooksBuffer() {
-  if (!bootstrapBuffer)
+function stopBootstrapHooksBuffer() {
+  if (!bootstrapHooks)
     return;
   async_hook_fields[kInit]--;
   async_hook_fields[kBefore]--;
@@ -299,19 +299,21 @@ function clearBootstrapHooksBuffer() {
   async_hook_fields[kPromiseResolve]--;
   async_hook_fields[kTotals] -= 5;
   active_hooks.array.splice(active_hooks.array.indexOf(bootstrapHooks), 1);
+  bootstrapHooks = null;
   if (async_hook_fields[kTotals] === 0) {
     disableHooks();
     // Flush microtasks to ensure disable has run.
     process._tickCallback();
   }
-  const _bootstrapBuffer = bootstrapBuffer;
+}
+
+function clearBootstrapHooksBuffer() {
+  if (bootstrapHooks)
+    stopBootstrapHooksBuffer();
   bootstrapBuffer = null;
-  bootstrapHooks = null;
-  return _bootstrapBuffer;
 }
 
 function emitBootstrapHooksBuffer() {
-  const bootstrapBuffer = clearBootstrapHooksBuffer();
   if (!bootstrapBuffer || async_hook_fields[kTotals] === 0) {
     return;
   }
@@ -331,6 +333,7 @@ function emitBootstrapHooksBuffer() {
         break;
     }
   }
+  bootstrapBuffer = null;
 }
 
 let wantPromiseHook = false;
@@ -573,5 +576,6 @@ module.exports = {
   },
   bufferBootstrapHooks,
   clearBootstrapHooksBuffer,
-  emitBootstrapHooksBuffer
+  emitBootstrapHooksBuffer,
+  stopBootstrapHooksBuffer
 };

lib/internal/modules/esm/module_job.js

@@ -11,7 +11,8 @@ const { ModuleWrap } = internalBinding('module_wrap');
 const { decorateErrorStack } = require('internal/util');
 const { getOptionValue } = require('internal/options');
 const assert = require('internal/assert');
-const { clearBootstrapHooksBuffer } = require('internal/async_hooks');
+const { clearBootstrapHooksBuffer, stopBootstrapHooksBuffer } =
+    require('internal/async_hooks');
 const resolvedPromise = SafePromise.resolve();
 
 function noop() {}
@@ -107,13 +108,14 @@ class ModuleJob {
     const module = await this.instantiate();
     const timeout = -1;
     const breakOnSigint = false;
+    if (this.isMain)
+      stopBootstrapHooksBuffer();
     const output = {
       module,
       result: module.evaluate(timeout, breakOnSigint)
     };
-    if (this.isMain) {
+    if (this.isMain)
       clearBootstrapHooksBuffer();
-    }
     return output;
   }
 }