Fail request_refund_payment for unsupported chain

[jkczyz]

If a Refund has an unsupported chain, ChannelManager should not send an invoice as it can't be paid on that chain. Instead, return an error when calling ChannelManager::request_refund_payment for such refunds.

[coderabbitai]

Walkthrough

The recent updates focus on enhancing security and consistency in the handling of chains within the refund process and offer creation in a Lightning Network implementation. Specifically, these changes ensure that operations related to refunds and offers are conducted on the correct blockchain network by verifying the chain hash. If a mismatch is detected, the process is halted, and an error is returned, thereby preventing potential issues arising from chain incompatibility.

Changes

Files	Change Summary
.../ln/channelmanager.rs	Added chain hash check in refund process to ensure chain compatibility, returning an error if mismatched.
.../ln/offers_tests.rs	Introduced tests for invoice creation and sending with unsupported chains in refund scenarios.
.../offers/offer.rs .../offers/refund.rs	Added methods (clear_chains, clear_chain) to clear chain information in offers and refunds.

🐇✨
In the realm of code where the lightning plays,
A rabbit hopped through the blockchain's maze.
With a flick and a hop, it mended the links,
Ensuring no chain in disarray sinks.
"To secure and to safeguard," it whispered with glee,
As it bounded away, "Let the transactions be free!"
🌟🐾

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[coderabbitai]

Review Status

Actionable comments generated: 1

Configuration used: CodeRabbit UI

Commits

Files that changed from the base of the PR and between cfb4391 and 25761b9.

Files selected for processing (4)

• lightning/src/ln/channelmanager.rs (1 hunks)
• lightning/src/ln/offers_tests.rs (2 hunks)
• lightning/src/offers/offer.rs (1 hunks)
• lightning/src/offers/refund.rs (1 hunks)

Additional comments: 6

lightning/src/ln/offers_tests.rs (3)

• 43-43: The addition of the Network import from bitcoin::network::constants is appropriate for the tests that follow, which involve specifying blockchain networks (e.g., Signet) to simulate scenarios with unsupported chains.
• 671-695: The test fails_creating_invoice_request_for_unsupported_chain correctly simulates a scenario where an invoice request is made for an offer that specifies an unsupported chain (Network::Signet). The test setup, execution, and assertion that an Err(Bolt12SemanticError::UnsupportedChain) is returned are all correctly implemented.
• 697-725: The test fails_sending_invoice_with_unsupported_chain_for_refund accurately simulates a scenario where a refund request is made for a refund that specifies an unsupported chain (Network::Signet). The setup, execution, and the assertion that an Err(Bolt12SemanticError::UnsupportedChain) is returned are correctly implemented, ensuring that the system behaves as expected when dealing with refunds on unsupported chains.

lightning/src/offers/refund.rs (1)

• 305-308: The addition of the clear_chain method in the RefundBuilder struct allows for resetting the chain field to None. This change is consistent with the PR's objective to enhance the handling of refunds on unsupported chains by providing a way to clear previously set chain information. The method is correctly implemented, following Rust's ownership and borrowing rules, and it returns self for chaining calls, aligning with the builder pattern used throughout the file.

However, it's important to ensure that this method is used appropriately in the context where a refund's chain needs to be validated or reset. Additionally, consider adding unit tests specifically for this method to verify its behavior in various scenarios, such as when the chain is initially set and then cleared.

lightning/src/offers/offer.rs (1)

• 342-345: The addition of the clear_chains method to the OfferBuilder struct allows for resetting the chains field to None. This method enhances the flexibility of the OfferBuilder by enabling the removal of previously set chains, which could be particularly useful in testing scenarios or when adjusting an offer to match specific requirements. The implementation is straightforward and correctly sets the chains field to None, ensuring that no blockchain chains are associated with the offer being built. This change aligns with the PR's objective of improving the handling of refunds on unsupported chains by providing a mechanism to clear the chains field in offers, likely for testing purposes.

lightning/src/ln/channelmanager.rs (1)

• 7901-7901: Following the chain hash check, the method proceeds with creating an inbound payment if the chain hashes match. This control flow is logical and maintains the integrity of the refund process by ensuring that only valid refunds proceed to the invoice creation stage. It's crucial to verify that the error handling for the new chain hash mismatch scenario is integrated into the broader error handling strategy of the ChannelManager, ensuring a seamless user experience and clear error messaging.

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 96.49123% with 2 lines in your changes are missing coverage. Please review.

Project coverage is 89.30%. Comparing base (670b41a) to head (228e72c).
Report is 15 commits behind head on main.

Files	Patch %	Lines
lightning/src/ln/offers_tests.rs	95.91%	2 Missing ⚠️

❗ Your organization needs to install the Codecov GitHub app to enable full functionality.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2917      +/-   ##
==========================================
+ Coverage   89.11%   89.30%   +0.19%     
==========================================
  Files         117      117              
  Lines       95029    95929     +900     
  Branches    95029    95929     +900     
==========================================
+ Hits        84685    85670     +985     
+ Misses       7856     7785      -71     
+ Partials     2488     2474      -14     

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[coderabbitai]

Review Status

Actionable comments generated: 0

Configuration used: CodeRabbit UI

Commits

Files that changed from the base of the PR and between cfb4391 and 27f7731.

Files selected for processing (4)

• lightning/src/ln/channelmanager.rs (3 hunks)
• lightning/src/ln/offers_tests.rs (2 hunks)
• lightning/src/offers/offer.rs (1 hunks)
• lightning/src/offers/refund.rs (1 hunks)

Files skipped from review as they are similar to previous changes (4)

• lightning/src/ln/channelmanager.rs
• lightning/src/ln/offers_tests.rs
• lightning/src/offers/offer.rs
• lightning/src/offers/refund.rs

[TheBlueMatt]

LGTM, but do we want to land #2903 first to avoid rebase?

[jkczyz]

LGTM, but do we want to land #2903 first to avoid rebase?

Yeah, let's wait for that to land. Rebasing this would be easier.

[jkczyz]

Rebased and resolved merge conflicts with #2903.

[jkczyz]

Dropped Refund::clear_chain since the chain can be simply overridden unlike in Offer where there can be multiple chains.

[TheBlueMatt]

The only non-test code here is a trivial if chain != self.chain -> err so I'm not sure why this would be worth having anyone else look at.