jQuery Widget or UiComponent mixin don't loading or loading randomized

[denis-g]

Maybe need additional fixes on #25587 request.

Preconditions (*)

1. Magento 2.4.x
2. Google Chrome 92 (cache disabled on devtools)

Steps to reproduce (*)

1. Fresh install m2 2.4.4 (also problem with all 2.4.x)
2. Dev mode on
3. Cache settings (all on, except for layout, block_html, full_page)
4. Create new theme (luma parent)

requirejs-config.js

var config = {
    map: {
        '*': {
            myWidget: 'Magento_Theme/js/my-widget'
        }
   },
   config: {
        mixins: {
            'Magento_Theme/js/my-widget': {
                'Magento_Theme/js/my-widget-mixin': true
            }
        }
    }
};

my-widget.js

define([
    'jquery',
    'jquery-ui-modules/widget'
], function ($) {
    'use strict';

    $.widget('mage.myWidget', {
        options: {
            color: 'red'
        },
        _create: function () {
            $('body').css('background-color', this.options.color);
        }
    });

    return $.mage.myWidget;
});

my-widget-mixin.js

define([
    'jquery',
    'jquery-ui-modules/widget'
], function ($) {
    'use strict';

    return function (widget) {
        $.widget('mage.myWidget', widget, {
            options: {
                color: 'green'
            }
        });

        return $.mage.myWidget;
    }
});

Expected result (*)

Mixin load and background is GREEN 🟢

Actual result (*)

Results depend on cache, opened devtools.

1. Init widget on js file – mixin don't load (or randomized loading, also loading when devtools opened)
   Background is RED 🔴 or GREEN 🟢

define([
    'jquery',
    'myWidget'
], function ($, myWidget) {
    'use strict';

    myWidget();
});

2. Init widget on phtml file – mixin don't load (or randomized loading, also loading when devtools opened)
   Background is RED 🔴 or GREEN 🟢

require([
    'jquery',
    'myWidget'
], function ($, myWidget) {
    'use strict';

    myWidget();
});

3. Init widget on js file (with mage) – mixin load (or randomized don't loading)
   Background is GREEN 🟢 or RED 🔴

require([
    'jquery',
    'mage/mage'
], function ($) {
    'use strict';

    $('body').mage('myWidget', {});
});

4. Init widget on js file (without alias) – mixin load (or randomized don't loading when devtools opened)
   Background is GREEN 🟢 or RED 🔴

define([
    'jquery',
    'Magento_Theme/js/my-widget'
], function ($, myWidget) {
    'use strict';

    myWidget();
});

5. ALSO, when widget don't load and when call widget again (click event, etc) – mixin load
   Background is RED 🔴, after event is GREEN 🟢

require([
    'jquery',
    'myWidget'
], function ($, myWidget) {
    'use strict';

    myWidget();

    $('.action.mixin').on('click', function () {
        myWidget();
    });
});

6. Init widget on phtml file with data-mage-init – mixin load (works perfectly, without background flashing and mixin preloading)
   Background is GREEN 🟢

<div data-mage-init='{"myWidget": {}}'></div>

7. Init widget on phtml file with js x-magento-init – mixin load (works perfectly, without background flashing and mixin preloading)
   Background is GREEN 🟢

<script type="text/x-magento-init">
    {
        "*": {
            "myWidget": {}
        }
    }
</script>

8. Init widget on js file (with mixins!) – mixin load (works perfectly, without background flashing and mixin preloading)
   Background is GREEN 🟢

define([
    'jquery',
    'mixins!myWidget'
], function ($, myWidget) {
    'use strict';

    myWidget();
});

---

Please provide Severity assessment for the Issue as Reporter. This information will help during Confirmation and Issue triage processes.

• Severity: S0 - Affects critical data or functionality and leaves users without workaround.
• Severity: S1 - Affects critical data or functionality and forces users to employ a workaround.
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• Severity: S3 - Affects non-critical data or functionality and does not force users to employ a workaround.
• Severity: S4 - Affects aesthetics, professional look and feel, “quality” or “usability”.

[m2-assistant]

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[ihor-sviziev]

+1. We also randomly having similar issue.
I think it’s not related to random file loading, as we’re using file bundling and both widget and mixin are inside single bundle. Almost all the time at first page view mixin doesn’t apply, but after page reload - it applies

[denis-g]

@ihor-sviziev yep. On bundle, merged, or single it doesn't matter. Core problem on matching mixin with widget/component and random apply.

Also similar issue #22338

[mrtuvn]

good call! Thanks you denis for some use-cases
cc: tag @krzksz here maybe he will give us more information

[krzksz]

The reproduction path looks quite clear and I would start by attaching a logger/debugger in https://github.com/magento/magento2/blob/2.4-develop/lib/web/mage/requirejs/mixins.js#L161 to see if mixins are not loaded because they are not seen by the plugin or the whole mechanism is completely ignored.

[m2-assistant]

Hi @engcom-Delta. Thank you for working on this issue.
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[ihor-sviziev]

FYI we just tried to debug this issue - that's definitely a very random issue, and it looks like it is related to async js execution/script loading. When the issue reproducing, the following core return false because in the RequireJS config, we don't have all maps and mixins yet.

magento2/lib/web/mage/requirejs/mixins.js

Line 161 in 97f0a1f

return this.getMixins(path).length;

It looks like the issue coming from using wrapping

(function() {
 ... requirejs-config.js content here
require.config(config);
})();

Or maybe it is related to require.config that probably works in an async way.

magento2/lib/internal/Magento/Framework/RequireJs/Config.php

Lines 79 to 85 in 7c6b636

	const PARTIAL_CONFIG_TEMPLATE = <<<config
	(function() {
	%config%
	require.config(config);
	})();
	config;

So far, fixing this issue won't be really easy, so I stopped the research.

BTW, if you'll try setting a breakpoint to that line, or even adding console.log - the issue won't reproduce OR will reproduce very-very rarely that makes debugging really hard.

Summary: the issue happening because of the missing the mixins! prefix. This prefix isn't getting added because of not fully loaded RequireJS config.

I even thought it might be related to

magento2/lib/web/mage/bootstrap.js

Line 21 in 7c6b636

setTimeout(mage.apply);

And, issue reproducing both with enabled and disabled

PS: @krzksz, I think now is your turn. We need your knowledge and skills to resolve such hard frontend issues.

[mrtuvn]

Can we have or create new option allow developer determine when and how script defer or async ?

Example if no specific we use async and if we specific

<script type="text/x-magento-init" defer>
//Code
</script>

Current magento only allow add defer tag script via xml. I think somewhere in the code collect and add this attribute. Can we have same approach for script in js or phtml ?

[ihor-sviziev]

@mrtuvn, as you see from the description, the case with <script type="text/x-magento-init">...</script> works fine

[mrtuvn]

https://github.com/magento/magento2/blob/2.4-develop/lib/web/requirejs/require.js#L1881 <= default we always have async true here. So basically all script loaded async will run as soon as it downloaded and may block parse html

[ihor-sviziev]

@mrtuvn, I'm pretty sure the issue isn't simple at all.