perf: avoid leaking memory when using populate() with QueryCursor b…

…ecause of reusing populate options with `_docs` Fix #11641
Automattic · May 6, 2022 · 55ff290 · 55ff290
1 parent 2091818
commit 55ff290
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Showing 2 changed files with 7 additions and 3 deletions.
diff --git a/lib/model.js b/lib/model.js
@@ -4574,9 +4574,9 @@ function populate(model, docs, options, callback) {
     }
     // If no models to populate but we have a nested populate,
     // keep trying, re: gh-8946
-    if (options.populate != null) {
-      const opts = utils.populate(options.populate).map(pop => Object.assign({}, pop, {
-        path: options.path + '.' + pop.path
+    if (populateOptions.populate != null) {
+      const opts = utils.populate(populateOptions.populate).map(pop => Object.assign({}, pop, {
+        path: populateOptions.path + '.' + pop.path
       }));
       return model.populate(docs, opts, callback);
     }

diff --git a/lib/utils.js b/lib/utils.js
@@ -516,6 +516,10 @@ exports.populate = function populate(path, select, model, match, options, subPop
   let obj = null;
   if (arguments.length === 1) {
     if (path instanceof PopulateOptions) {
+      // If reusing old populate docs, avoid reusing `_docs` because that may
+      // lead to bugs and memory leaks. See gh-11641
+      path._docs = [];
+      path._childDocs = [];
       return [path];
     }