From 6419a8787f2b4ce2dbaaf143dcfa0cd1feb733e9 Mon Sep 17 00:00:00 2001
From: Valeri Karpov <val@karpov.io>
Date: Mon, 16 Oct 2023 17:15:01 -0400
Subject: [PATCH] fix(populate): handle multiple spaces when specifying paths
 to populate using space-delimited paths

Fix #13951
---
 lib/utils.js                | 13 ++++++++-----
 test/model.populate.test.js | 21 +++++++++++++++++++++
 2 files changed, 29 insertions(+), 5 deletions(-)

diff --git a/lib/utils.js b/lib/utils.js
index b5f3dd4acfc..4fca9502d56 100644
--- a/lib/utils.js
+++ b/lib/utils.js
@@ -31,6 +31,9 @@ exports.isMongooseDocumentArray = isMongooseDocumentArray.isMongooseDocumentArra
 exports.registerMongooseArray = isMongooseArray.registerMongooseArray;
 exports.registerMongooseDocumentArray = isMongooseDocumentArray.registerMongooseDocumentArray;
 
+const oneSpaceRE = /\s/;
+const manySpaceRE = /\s+/;
+
 /**
  * Produces a collection name from model `name`. By default, just returns
  * the model name
@@ -572,8 +575,8 @@ exports.populate = function populate(path, select, model, match, options, subPop
   function makeSingles(arr) {
     const ret = [];
     arr.forEach(function(obj) {
-      if (/[\s]/.test(obj.path)) {
-        const paths = obj.path.split(' ');
+      if (oneSpaceRE.test(obj.path)) {
+        const paths = obj.path.split(manySpaceRE);
         paths.forEach(function(p) {
           const copy = Object.assign({}, obj);
           copy.path = p;
@@ -592,9 +595,9 @@ function _populateObj(obj) {
   if (Array.isArray(obj.populate)) {
     const ret = [];
     obj.populate.forEach(function(obj) {
-      if (/[\s]/.test(obj.path)) {
+      if (oneSpaceRE.test(obj.path)) {
         const copy = Object.assign({}, obj);
-        const paths = copy.path.split(' ');
+        const paths = copy.path.split(manySpaceRE);
         paths.forEach(function(p) {
           copy.path = p;
           ret.push(exports.populate(copy)[0]);
@@ -609,7 +612,7 @@ function _populateObj(obj) {
   }
 
   const ret = [];
-  const paths = obj.path.split(' ');
+  const paths = oneSpaceRE.test(obj.path) ? obj.path.split(manySpaceRE) : [obj.path];
   if (obj.options != null) {
     obj.options = clone(obj.options);
   }
diff --git a/test/model.populate.test.js b/test/model.populate.test.js
index c1007f69315..00d16d01b6c 100644
--- a/test/model.populate.test.js
+++ b/test/model.populate.test.js
@@ -2819,7 +2819,28 @@ describe('model: populate:', function() {
 
       assert.equal(blogposts[0].user.name, 'Fan 1');
       assert.equal(blogposts[0].title, 'Test 1');
+    });
+
+    it('handles multiple spaces in between paths to populate (gh-13951)', async function() {
+      const BlogPost = db.model('BlogPost', new Schema({
+        title: String,
+        user: { type: ObjectId, ref: 'User' },
+        fans: [{ type: ObjectId, ref: 'User' }]
+      }));
+      const User = db.model('User', new Schema({ name: String }));
+
+      const fans = await User.create([{ name: 'Fan 1' }]);
+      const posts = [
+        { title: 'Test 1', user: fans[0]._id, fans: [fans[0]._id] }
+      ];
+      await BlogPost.create(posts);
+      const blogPost = await BlogPost.
+        findOne({ title: 'Test 1' }).
+        populate('user   \t fans');
 
+      assert.equal(blogPost.user.name, 'Fan 1');
+      assert.equal(blogPost.fans[0].name, 'Fan 1');
+      assert.equal(blogPost.title, 'Test 1');
     });
 
     it('maps results back to correct document (gh-1444)', async function() {