Fix unused parameter phpcs sniffs

[reykjalin]

Description

This is a follow up to #8415 where there are some issues reported by phpcs that were not a straight-forward fix.

Running

./vendor/bin/phpcs --standard=phpcs.xml.dist $(git ls-files | grep '.php$') --sniffs='VariableAnalysis.CodeAnalysis.VariableAnalysis'

Results in a list of issues in these files (also a command to get just the list of files)

./vendor/bin/phpcs --standard=phpcs.xml.dist $(git ls-files | grep '.php$') --sniffs='VariableAnalysis.CodeAnalysis.VariableAnalysis' | rg 'FILE' | sed 's/FILE: \/path\/to\/wcpay\/repo\/parent\/woocommerce-payments\//* '

• tests/unit/subscriptions/test-class-wc-payments-subscription-service.php
• tests/unit/subscriptions/test-class-wc-payments-subscriptions-event-handler.php
• includes/payment-methods/class-upe-payment-method.php
• tests/unit/subscriptions/test-class-wc-payments-subscriptions-migrator.php
• includes/multi-currency/Analytics.php
• includes/multi-currency/FrontendCurrencies.php
• tests/unit/test-class-compatibility-service.php
• src/Internal/Payment/State/AbstractPaymentState.php
• tests/unit/multi-currency/test-class-multi-currency.php
• tests/unit/test-class-wc-payments-features.php
• tests/unit/helpers/class-wc-helper-product-add-ons-helper.php
• includes/class-wc-payments-incentives-service.php
• tests/unit/test-class-wc-payment-gateway-wcpay-payment-types.php
• tests/unit/core/server/request/test-trait-order-info.php
• tests/unit/helpers/class-wc-helper-subscriptions-synchroniser.php
• tests/unit/multi-currency/compatibility/test-class-woocommerce-subscriptions.php
• includes/class-logger.php
• includes/multi-currency/MultiCurrency.php
• tests/unit/multi-currency/test-class-analytics.php
• tests/unit/test-class-wc-payment-gateway-wcpay-process-payment.php
• includes/wc-payment-api/class-wc-payments-api-client.php
• includes/admin/class-wc-payments-admin-sections-overwrite.php
• tests/unit/subscriptions/test-class-wc-payments-invoice-service.php
• tests/unit/test-class-wc-payment-gateway-wcpay-subscriptions-payment-method-order-note.php
• tests/unit/subscriptions/test-class-wc-payments-subscription-change-payment-method.php
• tests/unit/test-class-wc-payment-gateway-wcpay-subscriptions-process-payment.php
• tests/unit/test-class-wc-payments-utils.php
• tests/unit/test-class-wc-payment-gateway-wcpay-subscriptions.php
• includes/class-wc-payments-webhook-processing-service.php
• includes/class-wc-payments.php
• includes/class-wc-payments-apple-pay-registration.php
• tests/unit/test-class-wc-payment-gateway-wcpay.php

These seem to be mostly valid cases. I'd love to see if we can maybe add some rule to phpcs.xml.dist that catches these valid cases, e.g. in filters and hooks.

Alternatively we could just ignore these outright. Either way we should go through all of these issues and either:

1. Fix the issue, if it exists;
2. Add ignores in-place via comments; or
3. Add an ignore to phpcs.xml.dist.

Acceptance criteria

No more issues reported by phpcs.

Tasks

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1. WooPay: Fix unused parameter phpcs sniffs #8652
   focus: woopay priority: low type: technical debt +3
2. Plugin: Fix unused parameter phpcs sniffs in tests #8653
   focus: architecture priority: low type: technical debt +3
3. Plugin: Fix unused parameter phpcs sniffs #8654
   focus: architecture priority: low type: technical debt +3
4. Multi-Currency: Fix unused parameter phpcs sniffs #8655
   focus: multi-currency priority: low type: technical debt +3
5. Accounts: Fix unused parameter phpcs sniffs #8656
   focus: account lifecycle priority: low type: technical debt +3
6. Checkout: Fix unused parameter phpcs sniffs #8657
   focus: checkout payments priority: low type: technical debt +3
7. Payments: Fix unused parameter phpcs sniffs #8658
   focus: payments acceptance & processing priority: low type: technical debt +3

[reykjalin]

Maybe https://github.com/sirbrillig/phpcs-variable-analysis/ could be a decent fit here to replace this set of rules?

[vbelolapotkov]

@reykjalin this one will need to be split into smaller issues. The same as we did for other recent phpcs issues. Could you please take care of it once you have time?

[reykjalin]

Yup, once #8556 has been merged we'll have some better tools and direction for managing this across the codebase so I'll split it then 👍

[reykjalin]

@vbelolapotkov I've split this up into what I think are correct focuses, but would appreciate a quick review that this is split up correctly 👍