From: Jukka Kurkela <jukka.kurkela@gmail.com>
Date: Tue, 19 May 2020 21:58:53 +0000 (+0300)
Subject: Detect data modifications with equal values (#7350)
X-Git-Tag: v3.0.0-beta.2~144
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=50f2a1097a7db459adf38a9e9981e7aa26967c72;p=thirdparty%2FChart.js.git

Detect data modifications with equal values (#7350)

Fix data shift-push with identical values
---

diff --git a/src/core/core.datasetController.js b/src/core/core.datasetController.js
index 110a6ca35..371c84360 100644
--- a/src/core/core.datasetController.js
+++ b/src/core/core.datasetController.js
@@ -235,6 +235,7 @@ export default class DatasetController {
 		this._parsing = false;
 		this._data = undefined;
 		this._dataCopy = undefined;
+		this._dataModified = false;
 		this._objectData = undefined;
 		this._labels = undefined;
 		this._scaleStacked = {};
@@ -359,7 +360,7 @@ export default class DatasetController {
 			me._data = convertObjectDataToArray(data);
 			me._objectData = data;
 		} else {
-			if (me._data === data && helpers.arrayEquals(data, me._dataCopy)) {
+			if (me._data === data && !me._dataModified && helpers.arrayEquals(data, me._dataCopy)) {
 				return false;
 			}
 
@@ -372,6 +373,8 @@ export default class DatasetController {
 			// Note: This is suboptimal, but better than always parsing the data
 			me._dataCopy = data.slice(0);
 
+			me._dataModified = false;
+
 			if (data && Object.isExtensible(data)) {
 				listenArrayEvents(data, me);
 			}
@@ -1111,6 +1114,7 @@ export default class DatasetController {
 	_onDataPush() {
 		const count = arguments.length;
 		this._insertElements(this.getDataset().data.length - count, count);
+		this._dataModified = true;
 	}
 
 	/**
@@ -1118,6 +1122,7 @@ export default class DatasetController {
 	 */
 	_onDataPop() {
 		this._removeElements(this._cachedMeta.data.length - 1, 1);
+		this._dataModified = true;
 	}
 
 	/**
@@ -1125,6 +1130,7 @@ export default class DatasetController {
 	 */
 	_onDataShift() {
 		this._removeElements(0, 1);
+		this._dataModified = true;
 	}
 
 	/**
@@ -1133,6 +1139,7 @@ export default class DatasetController {
 	_onDataSplice(start, count) {
 		this._removeElements(start, count);
 		this._insertElements(start, arguments.length - 2);
+		this._dataModified = true;
 	}
 
 	/**
@@ -1140,6 +1147,7 @@ export default class DatasetController {
 	 */
 	_onDataUnshift() {
 		this._insertElements(0, arguments.length);
+		this._dataModified = true;
 	}
 }
 
diff --git a/test/specs/core.datasetController.tests.js b/test/specs/core.datasetController.tests.js
index d2bd407d5..4c21f1a0a 100644
--- a/test/specs/core.datasetController.tests.js
+++ b/test/specs/core.datasetController.tests.js
@@ -343,6 +343,32 @@ describe('Chart.DatasetController', function() {
 		expect(meta.data.length).toBe(42);
 	});
 
+	// https://github.com/chartjs/Chart.js/issues/7243
+	it('should re-synchronize metadata when data is moved and values are equal', function() {
+		var data = [10, 10, 10, 10, 10, 10];
+		var chart = acquireChart({
+			type: 'line',
+			data: {
+				labels: ['a', 'b', 'c', 'd', 'e', 'f'],
+				datasets: [{
+					data,
+					fill: true
+				}]
+			}
+		});
+
+		var meta = chart.getDatasetMeta(0);
+
+		expect(meta.data.length).toBe(6);
+		const firstX = meta.data[0].x;
+
+		data.push(data.shift());
+		chart.update();
+
+		expect(meta.data.length).toBe(6);
+		expect(meta.data[0].x).toEqual(firstX);
+	});
+
 	it('should re-synchronize metadata when scaleID changes', function() {
 		var chart = acquireChart({
 			type: 'line',