Quick exit the legend fit function when the legend is not displayed (#8161)

When the legend is not displayed, there are no guarantees that the
format of the options dictionary is correct. Rather than performing
computations and then exiting without using the results, we can instead
exit quickly since the size of the legend will be (0, 0) if not displayed

diff --git a/src/plugins/plugin.legend.js b/src/plugins/plugin.legend.js
index 529f82a773e99260a3a5fa20cc37e9425d6abcd0..e90e58816950f4ab12362c71ae2fbec6401a925f 100644 (file)
--- a/src/plugins/plugin.legend.js
+++ b/src/plugins/plugin.legend.js
@@ -183,6 +183,16 @@ export class Legend extends Element {
                const labelOpts = opts.labels;
                const display = opts.display;
 
+               // The legend may not be displayed for a variety of reasons including
+               // the fact that the defaults got set to `false`.
+               // When the legend is not displayed, there are no guarantees that the options
+               // are correctly formatted so we need to bail out as early as possible.
+               const minSize = me._minSize;
+               if (!display) {
+                       me.width = minSize.width = me.height = minSize.height = 0;
+                       return;
+               }
+
                const ctx = me.ctx;
                const labelFont = toFont(labelOpts.font, me.chart.options.font);
                const fontSize = labelFont.size;
@@ -192,8 +202,6 @@ export class Legend extends Element {
 
                // Reset hit boxes
                const hitboxes = me.legendHitBoxes = [];
-
-               const minSize = me._minSize;
                const isHorizontal = me.isHorizontal();
                const titleHeight = me._computeTitleHeight();
 
@@ -205,11 +213,6 @@ export class Legend extends Element {
                        minSize.height = me.maxHeight; // fill all the height
                }
 
-               // Increase sizes here
-               if (!display) {
-                       me.width = minSize.width = me.height = minSize.height = 0;
-                       return;
-               }
                ctx.font = labelFont.string;
 
                if (isHorizontal) {

diff --git a/test/specs/plugin.legend.tests.js b/test/specs/plugin.legend.tests.js
index 36a3439f4749e8ab5774dbfa7db53cd918aa9fef..2a333fed4f9bb91ab5856605827e4e94e6f6fbf7 100644 (file)
--- a/test/specs/plugin.legend.tests.js
+++ b/test/specs/plugin.legend.tests.js
@@ -706,6 +706,34 @@ describe('Legend block tests', function() {
                }]);
        });
 
+       it('should not crash when the legend defaults are false', function() {
+               const oldDefaults = Chart.defaults.plugins.legend;
+
+               Chart.defaults.set({
+                       plugins: {
+                               legend: false,
+                       },
+               });
+
+               var chart = window.acquireChart({
+                       type: 'doughnut',
+                       data: {
+                               datasets: [{
+                                       label: 'dataset1',
+                                       data: [1, 2, 3, 4]
+                               }],
+                               labels: ['', '', '', '']
+                       },
+               });
+               expect(chart).toBeDefined();
+
+               Chart.defaults.set({
+                       plugins: {
+                               legend: oldDefaults,
+                       },
+               });
+       });
+
        describe('config update', function() {
                it ('should update the options', function() {
                        var chart = acquireChart({