fix(connectors): graceful response deserialization for klarna

[sai-harsha-vardhan]

Summary

Adds graceful response deserialization fixes for the Klarna connector:

Changes

• Added #[serde(other)] Unknown variant to KlarnaFraudStatus enum (used in authorize response for SDK payments)
• Added #[serde(other)] Unknown variant to KlarnaCheckoutStatus enum (used in authorize response for redirect payments)
• Added #[serde(other)] Unknown variant to KlarnaPaymentStatus enum (used in payment sync response)
• Each Unknown match arm logs a warning and returns Pending status (preserves existing state rather than failing)

Notes

• No #[serde(deny_unknown_fields)] attributes existed on any Klarna response structs — no Fix 1 changes needed
• All response enum fields are used in business logic — no Fix 3 changes needed
• Compilation was blocked by a pre-existing issue in hyperswitch_interfaces unrelated to Klarna

[semanticdiff-com]

Review changes with  

Changed Files

File	Status
crates/hyperswitch_connectors/src/connectors/klarna/transformers.rs	0% smaller

[XyneSpaces]

Review: Graceful Response Deserialization for Klarna

✅ Approved

This PR applies the standard graceful deserialization fixes to the Klarna connector:

1. Fix 2 (Enum catch-alls): Added #[serde(other)] Unknown variants to:

   • KlarnaFraudStatus (used in SDK authorize response)
   • KlarnaCheckoutStatus (used in redirect authorize response)
   • KlarnaPaymentStatus (used in PSync response)

2. Warning logs and state preservation: All Unknown variants log warnings and return Pending status to preserve existing payment state rather than failing.

💡 Findings

1. Clean separation of concerns
Each enum has its own handler function (get_fraud_status, get_checkout_status, From<KlarnaPaymentStatus>) with consistent warning log patterns.

2. Appropriate fallback choice
Pending is the correct fallback for all Unknown variants — we don't know the actual state and shouldn't mark payments as failed/charged incorrectly.

🔍 Nit

The warning log messages vary slightly in format between the three handlers. Consider standardizing to a consistent pattern for easier log parsing:

• "Unknown Klarna {fraud/checkout/payment} status received, preserving current state"

Verdict: Clean implementation following established patterns. Ready to merge.