Document UGX exclusion and hardcode Stripe decimal lists (#4542)

* Address review comments on #4541: document UGX exclusion, hardcode Stripe decimal lists

- Rename STRIPE_ZERO_DECIMAL_CURRENCIES to STRIPE_ZERO_DECIMAL_CHARGE_CURRENCIES
  and document why UGX is excluded (zero-decimal per Stripe's list, but its
  special-case row requires charge amounts x100), plus ISK/HUF/TWD notes.
- Replace the CLDR-based three-decimal check with a hardcoded
  STRIPE_THREE_DECIMAL_CURRENCIES list (BHD, JOD, KWD, OMR, TND); drop the
  Symfony Intl dependency from this helper.
- Reword the StripeTest comment to state the UGX exception explicitly.

* Extend Stripe currency test coverage in #4541 follow-up

- getAmountInMinorUnits: add BHD (second three-decimal code), AFN/YER
  (more CLDR-zero codes Stripe charges x100), TWD (payout-zero/charge-two
  special case), unknown-code fallback (XXX) and lowercase inputs.
- Add getAmountFromMinorUnits round-trip test via invokePrivateMethod so the
  read-back path is covered too.

src/library/Payment/Adapter/Stripe.php

@@ -22,11 +22,22 @@ use FOSSBilling\Doctrine\EntityManagerFactory;
 use FOSSBilling\Doctrine\NamedLock;
 use FOSSBilling\Period;
 use Stripe\StripeClient;
-use Symfony\Component\Intl\Currencies;
 
 class Payment_Adapter_Stripe implements FOSSBilling\InjectionAwareInterface, FOSSBilling\Payment\JsonWebhookAuthenticatorInterface
 {
-    private const array STRIPE_ZERO_DECIMAL_CURRENCIES = ['BIF', 'CLP', 'DJF', 'GNF', 'JPY', 'KMF', 'KRW', 'MGA', 'PYG', 'RWF', 'VND', 'VUV', 'XAF', 'XOF', 'XPF'];
+    /**
+     * Stripe's zero-decimal currencies for charges (https://docs.stripe.com/currencies).
+     * UGX is on Stripe's published zero-decimal list, but its special-case row requires charge amounts ×100,
+     * so it is deliberately excluded here. ISK was never on the list and likewise uses two decimals for
+     * charges; HUF and TWD are zero-decimal for payouts only, so they stay ×100 here. This helper is
+     * charge-side only (PaymentIntents, Prices) and must not be reused for payouts.
+     */
+    private const array STRIPE_ZERO_DECIMAL_CHARGE_CURRENCIES = ['BIF', 'CLP', 'DJF', 'GNF', 'JPY', 'KMF', 'KRW', 'MGA', 'PYG', 'RWF', 'VND', 'VUV', 'XAF', 'XOF', 'XPF'];
+
+    /**
+     * Stripe's three-decimal currencies for charges (https://docs.stripe.com/currencies).
+     */
+    private const array STRIPE_THREE_DECIMAL_CURRENCIES = ['BHD', 'JOD', 'KWD', 'OMR', 'TND'];
 
     protected ?Pimple\Container $di = null;
 
@@ -262,17 +273,18 @@ class Payment_Adapter_Stripe implements FOSSBilling\InjectionAwareInterface, FOS
     }
 
     /**
-     * Stripe's own decimal rules, not CLDR's: Stripe's zero-decimal currencies are sent as-is, three-decimal ones
-     * keep three digits, and every other currency (including COP, HUF, IDR, ISK, PKR and UGX, which CLDR lists with
-     * no decimals) is sent ×100. See https://docs.stripe.com/currencies.
+     * Stripe's own decimal rules, not CLDR's: the currencies in STRIPE_ZERO_DECIMAL_CHARGE_CURRENCIES are sent
+     * as-is, the ones in STRIPE_THREE_DECIMAL_CURRENCIES keep three digits, and every other currency
+     * (including COP, HUF, IDR, ISK, PKR and UGX, which CLDR lists with no decimals) is sent ×100.
+     * See https://docs.stripe.com/currencies.
      */
     private function getCurrencyFractionDigits(string $currency): int
     {
         $currency = strtoupper($currency);
-        if (in_array($currency, self::STRIPE_ZERO_DECIMAL_CURRENCIES, true)) {
+        if (in_array($currency, self::STRIPE_ZERO_DECIMAL_CHARGE_CURRENCIES, true)) {
             return 0;
         }
-        if (Currencies::exists($currency) && Currencies::getFractionDigits($currency) === 3) {
+        if (in_array($currency, self::STRIPE_THREE_DECIMAL_CURRENCIES, true)) {
             return 3;
         }
 

tests/Unit/Payment/Adapter/StripeTest.php

@@ -2664,9 +2664,9 @@ describe('processTransaction payload handling', function (): void {
 });
 
 describe('getAmountInMinorUnits follows Stripe currency rules', function (): void {
-    // Stripe's zero-decimal list is "BIF CLP DJF GNF JPY KMF KRW MGA PYG RWF UGX VND VUV XAF XOF XPF", and ISK and UGX must
-    // be sent as two-decimal values (https://docs.stripe.com/currencies). Symfony Intl reports COP, HUF, IDR, ISK, PKR, UGX
-    // and others with no decimals, but Stripe expects them ×100.
+    // Stripe lists "BIF CLP DJF GNF JPY KMF KRW MGA PYG RWF UGX VND VUV XAF XOF XPF" as zero-decimal, but its
+    // special-cases row requires UGX charges ×100, like ISK (https://docs.stripe.com/currencies). Symfony Intl
+    // reports COP, HUF, IDR, ISK, PKR, UGX and others with no decimals, but Stripe expects them ×100.
     test('sends the invoice total in the unit Stripe expects', function (string $currency, int $expected): void {
         $invoice = createEntity(Invoice::class);
         $invoice->id = 5;
@@ -2683,11 +2683,30 @@ describe('getAmountInMinorUnits follows Stripe currency rules', function (): voi
         'USD' => ['USD', 100000],
         'JPY (zero-decimal)' => ['JPY', 1000],
         'KWD (three-decimal)' => ['KWD', 1000000],
+        'BHD (three-decimal)' => ['BHD', 1000000],
         'COP' => ['COP', 100000],
         'HUF' => ['HUF', 100000],
         'IDR' => ['IDR', 100000],
         'ISK (two-decimal representation)' => ['ISK', 100000],
         'PKR' => ['PKR', 100000],
         'UGX (two-decimal representation)' => ['UGX', 100000],
+        'AFN' => ['AFN', 100000],
+        'YER' => ['YER', 100000],
+        'TWD (two-decimal for charges)' => ['TWD', 100000],
+        'unknown code falls back to two decimals' => ['XXX', 100000],
+        'lowercase USD' => ['usd', 100000],
+        'lowercase JPY' => ['jpy', 1000],
+    ]);
+
+    test('reads Stripe amounts back in the same unit', function (string $currency, int $minorUnits, float $expected): void {
+        expect(invokePrivateMethod($this->adapter, 'getAmountFromMinorUnits', [$minorUnits, $currency]))->toBe($expected);
+    })->with([
+        'USD' => ['USD', 100000, 1000.0],
+        'JPY (zero-decimal)' => ['JPY', 1000, 1000.0],
+        'KWD (three-decimal)' => ['KWD', 1000000, 1000.0],
+        'HUF' => ['HUF', 100000, 1000.0],
+        'UGX (two-decimal representation)' => ['UGX', 100000, 1000.0],
+        'unknown code falls back to two decimals' => ['XXX', 100000, 1000.0],
+        'lowercase currency' => ['usd', 100000, 1000.0],
     ]);
 });