fix(connectors): graceful response deserialization for finix

[sai-harsha-vardhan]

Summary

This PR applies the three standard graceful response deserialization fixes to the Finix connector:

Fix 1 — Removed deny_unknown_fields

• No #[serde(deny_unknown_fields)] existed on any response structs in this connector

Fix 2 — Added catch-all variant to response enums used in business logic

• Added #[serde(other)] Unknown variant to FinixDisputeState
• Updated webhook match arms to return EventNotSupported and log a warning for unknown dispute states

Fix 3 — Made unused response fields opaque optional types

• tags (HashMap/FinixTags) → Option<Secret<serde_json::Value>> in FinixPaymentsResponse, FinixIdentityResponse, FinixInstrumentResponse
• entity (HashMap) → Option<Secret<serde_json::Value>> in FinixIdentityResponse
• three_d_secure (nested struct) → Option<Secret<serde_json::Value>> in FinixPaymentsResponse
• instrument_type (enum) → Option<Secret<String>> in FinixInstrumentResponse
• card_type (enum) → Option<Secret<String>> in FinixInstrumentResponse
• address (nested struct) → Option<Secret<serde_json::Value>> in FinixInstrumentResponse
• created_at, updated_at, application, created_via, identity → made optional and/or wrapped in Secret<String> as needed

Files Changed

• crates/hyperswitch_connectors/src/connectors/finix/transformers/response.rs
• crates/hyperswitch_connectors/src/connectors/finix/transformers.rs

[semanticdiff-com]

Review changes with  

Changed Files

File	Status
crates/hyperswitch_connectors/src/connectors/finix/transformers/response.rs	22% smaller
crates/hyperswitch_connectors/src/connectors/worldpaymodular/transformers/response.rs	1% smaller
crates/hyperswitch_connectors/src/connectors/bankofamerica/transformers.rs	0% smaller
crates/hyperswitch_connectors/src/connectors/checkout/transformers.rs	0% smaller
crates/hyperswitch_connectors/src/connectors/cybersource.rs	0% smaller
crates/hyperswitch_connectors/src/connectors/finix/transformers.rs	0% smaller
crates/hyperswitch_connectors/src/connectors/worldpaymodular/transformers.rs	0% smaller

[XyneSpaces]

Review: Finix Graceful Response Deserialization

💡 Suggestion: Consider clarifying comment for Unknown mapping

The FinixDisputeState::Unknown variant maps to EventNotSupported, which is appropriate. However, consider adding a brief inline comment explaining why this doesn't return an error, unlike typical webhook parsing failures.

FinixDisputeState::Unknown => {
    // Unknown dispute states are explicitly non-fatal to prevent 
    // breaking webhook processing when Finix adds new states
    router_env::logger::warn!("Received unknown Finix dispute state in webhook");
    Ok(IncomingWebhookEvent::EventNotSupported)
}

🔍 Nit: Redundant FinixTags type alias

The FinixTags type alias appears to be removed from usage but the import may remain. Verify that use std::collections::HashMap; and any FinixTags type definition can also be removed if no longer used.

Verdict: Implementation follows the graceful deserialization pattern correctly. Minor documentation suggestions only.

[XyneSpaces]

💡 Consider adding a brief comment explaining why Unknown maps to EventNotSupported rather than an error, for future maintainers.

[XyneSpaces]

🔍 Verify that the FinixTags type definition and HashMap import can be removed if no longer referenced elsewhere.

[XyneSpaces]

Review Summary

Verdict: ✅ Approve

Classification: Connector - graceful response deserialization fixes
Risk: Low

This PR applies standard graceful response deserialization patterns across multiple connectors (Finix, BankOfAmerica, Checkout, Cybersource, WorldpayModular). Changes follow the established connector patterns for handling unknown enum variants and securing unused response fields.

Findings

💡 1. Consistent pattern application for graceful deserialization

All modified connectors now have #[serde(other)] Unknown variants on response enums and wrap unused fields in Secret<serde_json::Value>>. This prevents production incidents when connectors add new fields or enum variants.

Files Reviewed

• crates/hyperswitch_connectors/src/connectors/finix/transformers/response.rs
• crates/hyperswitch_connectors/src/connectors/finix/transformers.rs
• crates/hyperswitch_connectors/src/connectors/bankofamerica/transformers.rs
• crates/hyperswitch_connectors/src/connectors/checkout/transformers.rs
• crates/hyperswitch_connectors/src/connectors/cybersource.rs
• crates/hyperswitch_connectors/src/connectors/worldpaymodular/transformers.rs
• crates/hyperswitch_connectors/src/connectors/worldpaymodular/transformers/response.rs

Pre-existing Issues (not introduced by this PR)

• None identified