Implement Price formatting ruleset for overriding currency symbol's per storefront and currency #5676

rickvdl · 2025-10-17T12:49:44Z

Based on this PoC PR.

We're having an issue related to currency formatting behavior in Romania (and possibly a few other currencies), internal discussion can be found here.

But some context: when using the Romanian Storefront, and a Romanian locale (ro_RO) prices are formatted as 1,23 RON, which is correct, but the more conventional way to write this in Romanian (according to reports) is 1,23 lei.

underlyingSK2Product.displayPrice uses the more common lei rather than RON, however the priceFormatter we create in SK2StoreProduct.swift through priceFormatterProvider.priceFormatterForSK2 based on the currency code and locale given to us by StoreKit creates strings using RON instead. This is causing discrepancies between localizedPriceString and the price strings we generate using the formatter (for example pricePerMonth) which looks confusing on the paywall especially.

After some research and discussions it looks like we can't get the NumberFormatter API to mimic the behavior of StoreKit, and thus we've been looking into an alternative approach.

We came up with a backend driven approach where we (given a ruleset) provide the option to override the currencySymbol for specific currency codes, given a storekit storefront (similar to what we already do for paywall localizations).

Checklist

If applicable, unit tests
If applicable, create follow-up issues for purchases-android and hybrids
Check if we need any web-billing specific implementations

Motivation

Description

Sources/Networking/Responses/OfferingsResponse.swift

rickvdl · 2025-10-17T12:51:53Z

Sources/Networking/Responses/OfferingsResponse.swift

    let uiConfig: UIConfig?
+    let config: Config?

+    public struct Config {


I added a Config 'envelope' here in order to future-proof ourselves for more configuration values. But we can also just call it priceFormattingRuleSets and only have this single purpose field here, happy to go either way

I'm fine either way too, but I can see us having this Config wrapper with a single key forever. I also wouldn't mind putting it in UIConfig.

Yep. I think we may as well put it in UIConfig, as one could argue that this affects UI (how prices are presented in the UI).

Good points, will move it to UIConfig

Moved them to UIConfig, however on tvOS it's an empty structure. I think this should still be supported on tvOS so added it to that struct as well. LMK if you (dis)agree

emerge-tools · 2025-10-17T12:52:28Z

1 build increased size

Name	Version	Download	Change	Install	Change	Approval
RevenueCat com.revenuecat.PaywallsTester	1.0 (1)	16.8 MB	⬆️ 38.8 kB (0.23%)	59.9 MB	⬆️ 144.6 kB (0.24%)	N/A

RevenueCat 1.0 (1)
com.revenuecat.PaywallsTester

⚖️ Compare build
⏱️ Analyze build performance

Total install size change: ⬆️ 144.6 kB (0.24%)
Total download size change: ⬆️ 38.8 kB (0.23%)

Largest size changes

Item	Install Size Change
DYLD.String Table	⬆️ 53.7 kB
📝 RevenueCat.CurrencySymbolOverridingPriceFormatter.CurrencySymbolO...	⬆️ 5.7 kB
DYLD.Exports	⬆️ 3.5 kB
Code Signature	⬆️ 3.4 kB
📝 RevenueCat.CurrencySymbolOverridingPriceFormatter.Objc Metadata	⬆️ 1.3 kB

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rickvdl · 2025-10-17T12:53:23Z

Sources/Purchasing/StoreKit2/ProductsFetcherSK2.swift

-            return Set(storeKitProducts.map { SK2StoreProduct(sk2Product: $0) })
+            return Set(storeKitProducts.map { SK2StoreProduct(
+                sk2Product: $0,
+                priceFormatterProvider: .init(priceFormattingRuleSet: priceFormattingRuleSetProvider.priceFormattingRuleSet())


This will hand the SKProduct the value type (PriceFormattingRuleSet) for the current storefront. However when the storefront changes the storekit cache is cleared and the storekit products are refetched, so I think this is fine

Sources/Purchasing/StoreKitAbstractions/SK1StoreProductDiscount.swift

rickvdl · 2025-10-17T12:54:08Z

Tests/StoreKitUnitTests/PriceFormatterProviderTests.swift

+        expect(priceFormatter.currencySymbol) == "RON"
+        XCTAssert(type(of: priceFormatter) == CurrencySymbolOverridingPriceFormatter.self)
+
+        XCTAssertEqual(priceFormatter.string(from: NSNumber(integerLiteral: 0)), "0,00 lei")


real world example

Sources/Purchasing/Purchases/Purchases.swift

rickvdl · 2025-10-17T12:55:43Z

@RCGitBot please test

emerge-tools · 2025-10-17T13:18:49Z

📸 Snapshot Test

240 unchanged

Name	Added	Removed	Modified	Renamed	Unchanged	Errored	Approval
RevenueCat com.revenuecat.PaywallsTester	0	0	0	0	240	0	N/A

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JayShortway

Some initial comments. Great job investigating this and adding support for this! 💪

JayShortway · 2025-10-20T09:39:25Z

Sources/Misc/PriceFormatterProvider.swift

+    /// Cardinal plural selection per CLDR/ICU baseline:
+    /// - Non-integers → .other
+    /// - Integers: 0 → .zero, 1 → .one, 2 → .two, else → .other
+    /// This function is intentionally locale-agnostic; apply your locale-specific rules upstream.
+    /// Spec reference: Unicode TR35 (Plural Rules).
+    private func rule(for value: NSNumber) -> PriceFormattingRuleSet.CurrencySymbolOverride.PluralRule {
+        let n = value.doubleValue
+
+        // Guard weird numerics
+        if n.isNaN || n.isInfinite { return .other }
+
+        guard let intValue = Int64(exactly: n) else {
+            return .other
+        }
+
+        // Check if value has any fractional part
+        let isInteger = n == Double(intValue)
+
+        // Per CLDR/ICU, decimals are "other" unless a locale defines explicit fraction rules.
+        guard isInteger else { return .other }
+
+        // Integer-only mapping; locale-specific categories like "few"/"many" are handled elsewhere.
+        switch intValue {
+        case 0: return .zero
+        case 1: return .one
+        case 2: return .two
+        default: return .other
+        }
+    }


I think this should follow the same rules as we use for VariableLocalizationKeys.

Should be matching now :)

JayShortway · 2025-10-20T09:45:01Z

Sources/Networking/Responses/OfferingsResponse.swift

    let uiConfig: UIConfig?
+    let config: Config?

+    public struct Config {


I'm fine either way too, but I can see us having this Config wrapper with a single key forever. I also wouldn't mind putting it in UIConfig.

Sources/Networking/Responses/OfferingsResponse.swift

ajpallares

Thank for tackling this!

On a quick initial review, I'm seeing some APIs made public, but, if I'm not wrong, I don't think any of these APIs should be public, as it's server-driven. Please correct me if I'm wrong 🙏

ajpallares · 2025-10-20T11:00:40Z

Sources/Misc/PriceFormatterProvider.swift

 /// A `NumberFormatter` provider class for prices.
 /// This provider caches the formatter to improve the performance.
-final class PriceFormatterProvider: Sendable {
+public final class PriceFormatterProvider: Sendable {


I wonder, why should this API be public? Its init is not public.
It seems to me like it's only public to allow StoreProduct's new init be public

convenience init( sk2Product: SK2Product, priceFormatterProvider: PriceFormatterProvider )

But I think that one shouldn't be public either?

@ajpallares indeed that's the reason, but this was already public. There also seems to be a public API tester for so I guess it is used by developers

I understand. It seems like that init was made public in #1341. But I don't see why the new init that receives a priceFormatterProvider needs to be public. Initially, I think we should not make it public unless we find a good reason. I would keep it internal so that PriceFormatterProvider can also be internal

Ah you're right, my bad! I've made it internal again :) Thanks for clarifying

Also, I would make this PriceFormatterProvider internal (probably we need it to be @_spi(Internal) public). I see that it's needed in the UIConfig's init that is already public (but that init should actually be @_spi(Internal) public instead).

I would add the @_spi(Internal) marker to that init in UIConfig to allow making this @_spi as well.
There's precedent: in #5208 we added the @_spi(Internal) marker to some existing public subtypes of UIConfig, with no complain from anyone as these APIs are not for public use.

(unresolving to make sure this is addressed)

Good point and agree, will make that change :)

ajpallares · 2025-10-20T11:12:27Z

Sources/Networking/Responses/OfferingsResponse.swift

    let uiConfig: UIConfig?
+    let config: Config?

+    public struct Config {


Yep. I think we may as well put it in UIConfig, as one could argue that this affects UI (how prices are presented in the UI).

Sources/Networking/Responses/OfferingsResponse.swift

ajpallares · 2025-10-20T15:20:40Z

Sources/Misc/PriceFormatterProvider.swift

 /// A `NumberFormatter` provider class for prices.
 /// This provider caches the formatter to improve the performance.
-final class PriceFormatterProvider: Sendable {
+public final class PriceFormatterProvider: Sendable {


Also, I would make this PriceFormatterProvider internal (probably we need it to be @_spi(Internal) public). I see that it's needed in the UIConfig's init that is already public (but that init should actually be @_spi(Internal) public instead).

I would add the @_spi(Internal) marker to that init in UIConfig to allow making this @_spi as well.
There's precedent: in #5208 we added the @_spi(Internal) marker to some existing public subtypes of UIConfig, with no complain from anyone as these APIs are not for public use.

ajpallares · 2025-10-20T15:21:35Z

Sources/Purchasing/StoreKitAbstractions/StoreProduct.swift

    @available(iOS 15.0, tvOS 15.0, watchOS 8.0, macOS 12.0, *)
-    public convenience init(sk2Product: SK2Product) {
-        self.init(SK2StoreProduct(sk2Product: sk2Product))
+    public convenience init(


Just to be sure: this one should be internal

Should be done :)

rickvdl · 2025-10-20T15:50:46Z

@RCGitBot please test

rickvdl · 2025-10-21T08:49:32Z

@RCGitBot please test

rickvdl · 2025-10-21T09:16:27Z

@RCGitBot please test

rickvdl · 2025-11-17T16:34:03Z

@RCGitBot please test

rickvdl · 2025-11-17T16:55:44Z

@RCGitBot please test

Sources/Networking/Responses/RevenueCatUI/UIConfig.swift

rickvdl · 2025-11-26T16:10:43Z

@RCGitBot please test

rickvdl · 2025-11-26T16:28:31Z

@RCGitBot please test

rickvdl · 2025-11-27T08:16:06Z

@RCGitBot please test

…urrent storefront

…ing UIConfig

… to improve testability

… product price formatting using the priceFormattingRuleSets

…o VariableHandlerV2's one

…ence type and update it's rule set whenever the offerings are received

…se because it also needs to work without paywalls

rickvdl · 2025-12-09T13:32:49Z

@RCGitBot please test

rickvdl added the pr:other label Oct 17, 2025

rickvdl commented Oct 17, 2025

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rickvdl commented Oct 17, 2025

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Sources/Purchasing/StoreKitAbstractions/SK1StoreProductDiscount.swift Outdated Show resolved Hide resolved

rickvdl commented Oct 17, 2025

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Sources/Purchasing/Purchases/Purchases.swift Outdated Show resolved Hide resolved

JayShortway reviewed Oct 20, 2025

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JayShortway requested a review from a team October 20, 2025 09:54

ajpallares reviewed Oct 20, 2025

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rickvdl force-pushed the rickvdl/price-formatting-ruleset-currency-symbol-override branch from b020ff5 to b4bdbf3 Compare October 20, 2025 14:42

ajpallares reviewed Oct 20, 2025

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rickvdl force-pushed the rickvdl/price-formatting-ruleset-currency-symbol-override branch from c52ff21 to c112d18 Compare October 21, 2025 08:53

rickvdl force-pushed the rickvdl/price-formatting-ruleset-currency-symbol-override branch 2 times, most recently from 5d82758 to b316ec3 Compare November 17, 2025 14:06

JayShortway reviewed Nov 18, 2025

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Sources/Networking/Responses/RevenueCatUI/UIConfig.swift Outdated Show resolved Hide resolved

rickvdl force-pushed the rickvdl/price-formatting-ruleset-currency-symbol-override branch 2 times, most recently from 805ab88 to 21dfe3c Compare November 26, 2025 16:10

rickvdl force-pushed the rickvdl/price-formatting-ruleset-currency-symbol-override branch from 4eab3f3 to 6fddc7c Compare November 27, 2025 08:16

rickvdl force-pushed the rickvdl/price-formatting-ruleset-currency-symbol-override branch from bbdfc29 to 3308827 Compare December 8, 2025 14:55

rickvdl added 26 commits December 9, 2025 13:37

PoC: allow overriding currencySymbol from a backend-provided ruleset

96f9cca

Cleaner way of getting the currency symbol override ruleset for the c…

1e37f0a

…urrent storefront

Code cleanup

a877254

Fixed a case where the wrong formatter might be used

22e900d

Implemented PriceFormatRuleset for web products as well

346d455

Added a bunch more unit tests

13956ae

Moved the priceFormattingRuleSets from new Config struct to the exist…

8fa0af7

…ing UIConfig

Made PriceFormatterProvider internal

ea2cbca

Made UIConfig struct internal

d9bc6aa

Fixed linting issues

ffde29f

Moved priceFormattingRuleSet provider logic to ProductsManagerFactory…

a8bdcc0

… to improve testability

Add ProductsManagerFactoryTests

51dbd39

Fixed few linting issues

bfb6a67

Added an integration test between offerings API -> product manager ->…

7721327

… product price formatting using the priceFormattingRuleSets

Implemented for SK1StoreProductDiscount as well

9307586

Matching CurrencySymbolOverridingPriceFormatter rule matching logic t…

23d6c29

…o VariableHandlerV2's one

Fixed swiftlint warnings

e0cf349

Updated approach to use the PriceFormattingRuleSetProvider as a refer…

2bab8e9

…ence type and update it's rule set whenever the offerings are received

Fixed test compilation

77b1503

Moved priceFormattingRuleSets to new Config struct in OfferingsRespon…

3f1afcb

…se because it also needs to work without paywalls

Removed public modifier

f98a3f6

Fix compile issue

ef93bbc

Fixed compilation on tvOS

c53f1b4

Implemented PR feedback

a47741c

Updated comment

1ffe2dc

Implemented PR feedback

a2b6935

rickvdl force-pushed the rickvdl/price-formatting-ruleset-currency-symbol-override branch from 3308827 to a2b6935 Compare December 9, 2025 12:37

fixed compilation

277ba35

Implement Price formatting ruleset for overriding currency symbol's per storefront and currency #5676

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Implement Price formatting ruleset for overriding currency symbol's per storefront and currency #5676

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Checklist

Motivation

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emerge-tools bot commented Oct 17, 2025 • edited Loading Uh oh! There was an error while loading. Please reload this page.

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1 build increased size

RevenueCat 1.0 (1)com.revenuecat.PaywallsTester

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rickvdl commented Oct 17, 2025

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rickvdl commented Oct 20, 2025

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rickvdl commented Oct 17, 2025 •

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RevenueCat 1.0 (1)
com.revenuecat.PaywallsTester

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