Merge pull request #15136 from Automattic/vkarpov15/gh-10449-2

perf(cursor): clear the stack every time if using populate with batchSize to avoid stack overflows with large docs

Author: vkarpov15

lib/cursor/queryCursor.js

@@ -557,17 +557,11 @@ function _onNext(error, doc) {
 
   if (this.ctx._batchDocs.length < this.ctx.options._populateBatchSize) {
     // If both `batchSize` and `_populateBatchSize` are huge, calling `next()` repeatedly may
-    // cause a stack overflow. So make sure we clear the stack regularly.
-    if (this.ctx._batchDocs.length > 0 && this.ctx._batchDocs.length % 1000 === 0) {
-      return immediate(() => this.ctx.cursor.next().then(
-        res => { _onNext.call(this, null, res); },
-        err => { _onNext.call(this, err); }
-      ));
-    }
-    this.ctx.cursor.next().then(
+    // cause a stack overflow. So make sure we clear the stack.
+    immediate(() => this.ctx.cursor.next().then(
       res => { _onNext.call(this, null, res); },
       err => { _onNext.call(this, err); }
-    );
+    ));
   } else {
     _populateBatch.call(this);
   }