Removes deprecated syntax usage in less files.

[hostep]

Description (*)

Some syntax in .less files is being deprecated. Magento uses some of them. This PR fixes this.
Here's an overview:

DEPRECATED WARNING: Calling a mixin without parentheses is deprecated in var/view_preprocessed/pub/static/adminhtml/Magento/backend/en_US/css/source/components/_slider.less on line 52, column 28
DEPRECATED WARNING: Whitespace between a mixin name and parentheses for a mixin call is deprecated in var/view_preprocessed/pub/static/adminhtml/Magento/backend/en_US/css/source/components/_file-uploader.less on line 118, column 24
DEPRECATED WARNING: Whitespace between a mixin name and parentheses for a mixin call is deprecated in var/view_preprocessed/pub/static/adminhtml/Magento/backend/en_US/css/source/components/_file-uploader.less on line 380, column 24
DEPRECATED WARNING: Whitespace between a mixin name and parentheses for a mixin call is deprecated in var/view_preprocessed/pub/static/adminhtml/Magento/backend/en_US/css/source/lib/_buttons.less on line 400, column 22
DEPRECATED WARNING: Whitespace between a mixin name and parentheses for a mixin call is deprecated in var/view_preprocessed/pub/static/adminhtml/Magento/backend/en_US/css/source/lib/_buttons.less on line 80, column 23
DEPRECATED WARNING: Whitespace between a mixin name and parentheses for a mixin call is deprecated in var/view_preprocessed/pub/static/adminhtml/Magento/backend/en_US/css/source/lib/_pages.less on line 275, column 30
DEPRECATED WARNING: Whitespace between a mixin name and parentheses for a mixin call is deprecated in var/view_preprocessed/pub/static/adminhtml/Magento/backend/en_US/css/source/lib/_pages.less on line 293, column 30
DEPRECATED WARNING: Whitespace between a mixin name and parentheses for a mixin call is deprecated in var/view_preprocessed/pub/static/adminhtml/Magento/backend/en_US/css/source/lib/_rating.less on line 178, column 19
DEPRECATED WARNING: Whitespace between a mixin name and parentheses for a mixin call is deprecated in var/view_preprocessed/pub/static/adminhtml/Magento/backend/en_US/Magento_AdminNotification/css/source/_module.less on line 112, column 29
DEPRECATED WARNING: Whitespace between a mixin name and parentheses for a mixin call is deprecated in var/view_preprocessed/pub/static/frontend/Magento/blank/en_US/css/source/lib/_buttons.less on line 400, column 22
DEPRECATED WARNING: Whitespace between a mixin name and parentheses for a mixin call is deprecated in var/view_preprocessed/pub/static/frontend/Magento/blank/en_US/css/source/lib/_buttons.less on line 80, column 23
DEPRECATED WARNING: Whitespace between a mixin name and parentheses for a mixin call is deprecated in var/view_preprocessed/pub/static/frontend/Magento/blank/en_US/css/source/lib/_pages.less on line 275, column 30
DEPRECATED WARNING: Whitespace between a mixin name and parentheses for a mixin call is deprecated in var/view_preprocessed/pub/static/frontend/Magento/blank/en_US/css/source/lib/_pages.less on line 293, column 30
DEPRECATED WARNING: Whitespace between a mixin name and parentheses for a mixin call is deprecated in var/view_preprocessed/pub/static/frontend/Magento/blank/en_US/css/source/lib/_rating.less on line 178, column 19
DEPRECATED WARNING: Whitespace between a mixin name and parentheses for a mixin call is deprecated in var/view_preprocessed/pub/static/frontend/Magento/luma/en_US/css/source/lib/_buttons.less on line 400, column 22
DEPRECATED WARNING: Whitespace between a mixin name and parentheses for a mixin call is deprecated in var/view_preprocessed/pub/static/frontend/Magento/luma/en_US/css/source/lib/_buttons.less on line 80, column 23
DEPRECATED WARNING: Whitespace between a mixin name and parentheses for a mixin call is deprecated in var/view_preprocessed/pub/static/frontend/Magento/luma/en_US/css/source/lib/_pages.less on line 275, column 30
DEPRECATED WARNING: Whitespace between a mixin name and parentheses for a mixin call is deprecated in var/view_preprocessed/pub/static/frontend/Magento/luma/en_US/css/source/lib/_pages.less on line 293, column 30
DEPRECATED WARNING: Whitespace between a mixin name and parentheses for a mixin call is deprecated in var/view_preprocessed/pub/static/frontend/Magento/luma/en_US/css/source/lib/_rating.less on line 178, column 19
DEPRECATED WARNING: Whitespace between a mixin name and parentheses for a mixin call is deprecated in var/view_preprocessed/pub/static/frontend/Magento/luma/en_US/Magento_Checkout/css/source/module/checkout/fields/_file-uploader.less on line 135, column 28
DEPRECATED WARNING: Whitespace between a mixin name and parentheses for a mixin call is deprecated in var/view_preprocessed/pub/static/frontend/Magento/luma/en_US/Magento_Checkout/css/source/module/checkout/fields/_file-uploader.less on line 398, column 28

Related Pull Requests

N/A

Fixed Issues (if relevant)

N/A

Manual testing scenarios (*)

1. Setup clean Magento
2. Run these commands to set everything up:

$ rm -Rf package-lock.json node_modules/ var/view_preprocessed/ pub/static/adminhtml/ pub/static/frontend/
$ cp package.json.sample package.json
$ npm install
$ composer require baldwin/magento2-module-less-js-compiler:dev-v1-develop
$ bin/magento setup:upgrade
$ bin/magento setup:static-content:deploy en_US -f
$ cp -r pub/static /tmp/magento-static-files-before-changes

4. Now upgrade less.js to latest version, as it has no more false positives in deprecated warnings, to do so, apply this change to the package.json file:

     "grunt-template-jasmine-requirejs": "~0.2.3",
     "grunt-text-replace": "~0.4.0",
     "imagemin-svgo": "~9.0.0",
-    "less": "4.2.2",
+    "less": "4.6.4",
     "load-grunt-config": "~4.0.1",
     "morgan": "~1.10.0",
     "node-minify": "~3.6.0",

5. Run these commands:

$ rm -Rf package-lock.json node_modules/ var/log/system.log var/view_preprocessed/ pub/static/adminhtml/ pub/static/frontend/
$ npm install
$ bin/magento setup:static-content:deploy en_US -f
$ grep 'deprecated' var/log/system.log

6. Notice that the grep command reveals ~93 deprecated warnings from the less compiler

7. Apply the changes from this PR

8. Run these commands:

$ rm -Rf var/log/system.log var/view_preprocessed/ pub/static/adminhtml/ pub/static/frontend/
$ bin/magento setup:static-content:deploy en_US -f
$ cp -r pub/static /tmp/magento-static-files-after-changes
$ grep 'deprecated' var/log/system.log

9. Verify no deprecated warnings from the grep command anymore

10. Also verify that no important changes happened in the outputted css files by diffing, only the deployed_version.txt file shows up with a change, but that's expected:

$ diff -ur /tmp/magento-static-files-before-changes/ /tmp/magento-static-files-after-changes/

Questions or comments

Should Adobe Commerce / B2B also be checked for the same? I don't have access to those codebases, so I can't help with those.

Contribution checklist (*)

• Pull request has a meaningful description of its purpose
• All commits are accompanied by meaningful commit messages
• All new or changed code is covered with unit/integration tests (if applicable)
• README.md files for modified modules are updated and included in the pull request if any README.md predefined sections require an update
• All automated tests passed successfully (all builds are green)

[m2-assistant]

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[hostep]

@magento run Static Tests

[hostep]

@magento run Static Tests

[hostep]

@magento run all tests