Polar Area elements.arc.angle option now returns degrees (#7871)

* Polar Area `elements.arc.angle` option now returns degrees
* Update wording of migration docs

docs/docs/getting-started/v3-migration.md

@@ -66,6 +66,7 @@ A number of changes were made to the configuration options passed to the `Chart`
 
 * `hover.animationDuration` is now configured in `animation.active.duration`
 * `responsiveAnimationDuration` is now configured in `animation.resize.duration`
+* Polar area `elements.arc.angle` is now configured in degrees instead of radians.
 * Polar area `startAngle` option is now consistent with `Radar`, 0 is at top and value is in degrees. Default is changed from `-½π` to  `0`.
 * Doughnut `rotation` option is now in degrees and 0 is at top. Default is changed from `-½π` to  `0`.
 * Doughnut `circumference` option is now in degrees. Default is changed from `2π` to `0`.

src/controllers/controller.polarArea.js

@@ -1,5 +1,5 @@
 import DatasetController from '../core/core.datasetController';
-import {resolve, toRadians, PI, TAU} from '../helpers/index';
+import {resolve, toRadians, PI} from '../helpers/index';
 
 function getStartAngleRadians(deg) {
 	// radialLinear scale draws angleLines using startAngle. 0 is expected to be at top.
@@ -121,10 +121,10 @@ export default class PolarAreaController extends DatasetController {
 		// Scriptable options
 		const context = me.getContext(index, mode === 'active');
 
-		return resolve([
+		return toRadians(resolve([
 			me.chart.options.elements.arc.angle,
-			TAU / count
-		], context, index);
+			360 / count
+		], context, index));
 	}
 }
 

test/fixtures/controller.polarArea/angle-array.json

@@ -19,7 +19,7 @@
             "elements": {
                 "arc": {
                     "angle": [
-                        1.0566, 1.7566, 1.0566, 2.1566, 0.2566
+                        60.5387, 100.6457, 60.5387, 123.5641, 14.7021
                     ]
                 }
             },

test/fixtures/controller.polarArea/border-align-center.json

@@ -26,7 +26,7 @@
             "elements": {
                 "arc": {
                     "angle": [
-                        0.0378, 0.1892, 0.3786, 1.8925, 3.7849
+                        2.1658, 10.8404, 21.6922, 108.4323, 216.8588
                     ]
                 }
             },

test/fixtures/controller.polarArea/border-align-inner.json

@@ -27,7 +27,7 @@
             "elements": {
                 "arc": {
                     "angle": [
-                        0.0378, 0.1892, 0.3786, 1.8925, 3.7849
+                        2.1658, 10.8404, 21.6922, 108.4323, 216.8588
                     ]
                 }
             },