From a01893b27547da2c72e5203fa99cdec106cef669 Mon Sep 17 00:00:00 2001
From: Andreas Hocevar <andreas.hocevar@gmail.com>
Date: Wed, 31 Mar 2021 18:17:04 +0200
Subject: [PATCH 1/2] VectorSource#getFeatures() consistently returns a new
 array

---
 src/ol/source/Vector.js | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/src/ol/source/Vector.js b/src/ol/source/Vector.js
index e686c8f335..6b68b481db 100644
--- a/src/ol/source/Vector.js
+++ b/src/ol/source/Vector.js
@@ -653,14 +653,15 @@ class VectorSource extends Source {
   }
 
   /**
-   * Get all features on the source in random order.
+   * Get all snapshot of the features currently on the source in random order. The returned array
+   * is a copy, the features are references to the features in the source.
    * @return {Array<import("../Feature.js").default<Geometry>>} Features.
    * @api
    */
   getFeatures() {
     let features;
     if (this.featuresCollection_) {
-      features = this.featuresCollection_.getArray();
+      features = this.featuresCollection_.getArray().slice(0);
     } else if (this.featuresRtree_) {
       features = this.featuresRtree_.getAll();
       if (!isEmpty(this.nullGeometryFeatures_)) {
@@ -700,7 +701,7 @@ class VectorSource extends Source {
     if (this.featuresRtree_) {
       return this.featuresRtree_.getInExtent(extent);
     } else if (this.featuresCollection_) {
-      return this.featuresCollection_.getArray();
+      return this.featuresCollection_.getArray().slice(0);
     } else {
       return [];
     }

From 59d686d10492b21b06ef49a2782c0e2da21dbb5e Mon Sep 17 00:00:00 2001
From: Andreas Hocevar <andreas.hocevar@gmail.com>
Date: Thu, 1 Apr 2021 08:38:29 +0200
Subject: [PATCH 2/2] Fix typo, add test

---
 src/ol/source/Vector.js            |  2 +-
 test/spec/ol/source/vector.test.js | 12 ++++++++++++
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/src/ol/source/Vector.js b/src/ol/source/Vector.js
index 6b68b481db..ce4d8a2ebc 100644
--- a/src/ol/source/Vector.js
+++ b/src/ol/source/Vector.js
@@ -653,7 +653,7 @@ class VectorSource extends Source {
   }
 
   /**
-   * Get all snapshot of the features currently on the source in random order. The returned array
+   * Get a snapshot of the features currently on the source in random order. The returned array
    * is a copy, the features are references to the features in the source.
    * @return {Array<import("../Feature.js").default<Geometry>>} Features.
    * @api
diff --git a/test/spec/ol/source/vector.test.js b/test/spec/ol/source/vector.test.js
index ad69fea674..6940d5fe6f 100644
--- a/test/spec/ol/source/vector.test.js
+++ b/test/spec/ol/source/vector.test.js
@@ -143,6 +143,18 @@ describe('ol.source.Vector', function () {
         expect(feature).to.be(features[0]);
       });
     });
+
+    describe('#getFeatures', function () {
+      it('does not return the internal array when useSpatialIndex is false', function () {
+        const noSpatialIndexSource = new VectorSource({
+          useSpatialIndex: false,
+          features: vectorSource.getFeatures(),
+        });
+        expect(noSpatialIndexSource.getFeatures()).to.not.be(
+          noSpatialIndexSource.getFeaturesCollection().getArray()
+        );
+      });
+    });
   });
 
   describe('clear and refresh', function () {