From fa9fb8a0f107337e4574c7f71bd3a438cdebeae8 Mon Sep 17 00:00:00 2001
From: Andrea Bogazzi <andreabogazzi79@gmail.com>
Date: Mon, 4 Jun 2018 11:13:39 +0200
Subject: [PATCH] fix group becoming cachrable (#5021)

* fix group becoming cacheable
---
 src/shapes/object.class.js |  3 +++
 test/unit/object.js        | 13 +++++++++----
 2 files changed, 12 insertions(+), 4 deletions(-)

diff --git a/src/shapes/object.class.js b/src/shapes/object.class.js
index 1e069bcd160..5052302e0b2 100644
--- a/src/shapes/object.class.js
+++ b/src/shapes/object.class.js
@@ -617,6 +617,8 @@
       this._cacheCanvas = fabric.document.createElement('canvas');
       this._cacheContext = this._cacheCanvas.getContext('2d');
       this._updateCacheCanvas();
+      // if canvas gets created, is empty, so dirty.
+      this.dirty = true;
     },
 
     /**
@@ -1002,6 +1004,7 @@
       if (this.shouldCache()) {
         if (!this._cacheCanvas) {
           this._createCacheCanvas();
+
         }
         if (this.isCacheDirty()) {
           this.statefullCache && this.saveState({ propertySet: 'cacheProperties' });
diff --git a/test/unit/object.js b/test/unit/object.js
index 8caa11924f2..9df3028feaa 100644
--- a/test/unit/object.js
+++ b/test/unit/object.js
@@ -1019,13 +1019,21 @@
     assert.equal(object.dirty, true, 'after setting a property from cache, dirty flag is true');
   });
 
+  QUnit.test('_createCacheCanvas sets object as dirty', function(assert) {
+    var object = new fabric.Object({ scaleX: 3, scaleY: 2, width: 1, height: 2});
+    assert.equal(object.dirty, true, 'object is dirty after creation');
+    object.dirty = false;
+    assert.equal(object.dirty, false, 'object is not dirty after specifying it');
+    object._createCacheCanvas();
+    assert.equal(object.dirty, true, 'object is dirty again if cache gets created');
+  });
+
   QUnit.test('isCacheDirty statefullCache disabled', function(assert) {
     var object = new fabric.Object({ scaleX: 3, scaleY: 2, width: 1, height: 2});
     assert.equal(object.dirty, true, 'object is dirty after creation');
     object.cacheProperties = ['propA', 'propB'];
     object.dirty = false;
     object.statefullCache = false;
-    object._createCacheCanvas();
     assert.equal(object.isCacheDirty(), false, 'object is not dirty if dirty flag is false');
     object.dirty = true;
     assert.equal(object.isCacheDirty(), true, 'object is dirty if dirty flag is true');
@@ -1038,9 +1046,6 @@
     object.statefullCache = true;
     object.propA = 'A';
     object.setupState({ propertySet: 'cacheProperties' });
-    object._createCacheCanvas();
-    assert.equal(object.isCacheDirty(), true, 'object is dirty if canvas has been just created');
-    object.setupState({ propertySet: 'cacheProperties' });
     assert.equal(object.isCacheDirty(), false, 'object is not dirty');
     object.propA = 'B';
     assert.equal(object.isCacheDirty(), true, 'object is dirty because change in propA is detected by statefullCache');