Legend position: 'chartArea' broken since v3.4.0 (works on 3.3.0)

[volfasengelman]

Expected Behavior

Chart loaded with Legend drawn on chart area, see fiddle - version 3.3.0

Current Behavior

Chart is not loaded, error in console.

Error can be reproduced in this fiddle

chart.esm.js:7584 Uncaught (in promise) TypeError: Cannot read properties of undefined (reading 'top')
    at Legend.setDimensions (chart.esm.js:7584)
    at Legend.update (chart.esm.js:7573)
    at eval (chart.esm.js:3038)
    at each (helpers.segment.js:224)
    at Object.update (chart.esm.js:3035)
    at Chart._updateLayout (chart.esm.js:5654)
    at Chart.update (chart.esm.js:5636)
    at Chart.eval (chart.esm.js:5390)
    at Chart.eval [as _doResize] (helpers.segment.js:159)
    at Chart._resize (chart.esm.js:5467)
    at Chart.resize (chart.esm.js:5446)
    at attached (chart.esm.js:5933)
    at Chart.bindResponsiveEvents (chart.esm.js:5945)
    at Chart.bindEvents (chart.esm.js:5889)
    at Chart._initialize (chart.esm.js:5432)
    at new Chart (chart.esm.js:5398)
    at ChartjsModule.redraw (chartjsModule.js:222)
    at eval (chart.js:321)

Possible Solution

downgrade or fix bug

Steps to Reproduce

Set Legend position to 'chartArea', as documented here

  options: {
    plugins: {
      legend: {
        position: 'chartArea'
        }
     }
  }

Open fiddle fiddle

Context

I cannot use legend layout 'cartArea'

Environment

• Chart.js version: 3.6.0
• Browser name and version: Chrome Version 96.0.4664.45 (Official Build) (64-bit)
• Link to your project: Open fiddle fiddle

[LeeLenaleee]

It comes from this pr: #9290 the margins are set in the first time it gets passed it but a second time for some reason it gets undefined passed. This breakes it since it cant read top and left from undefined.

Only workaround I can think of is checking is its unefined and if so dont update the margins but I think the issue should be solved in the place where it is getting made undefined

[etimberg]

I have a possible fix in #9915. Items on the chart area don't have margins, but instead of sending undefined it now sends an object indicating that the margins are 0

[egisz]

Thanks! I checked and now it works as expected :)