PDK Dev Call - June 16th 2025

[arminsabouri]

PDK Dev Call – June 16th 2025

Armin

• Opened PR Replace Persister with SessionPersister for v2::Receiver #750 to wire receiver state transitions with the new session persister trait.
• Split out smaller supporting changes into Receiver Session Events #760, Export InMemoryTestPersister under _test-utils #761 , Capture hpke reply key in session event #762 .
• Tried refactoring receiver state transition methods to save session events internally, but decided it wasn’t worth the added complexity. See notes in Replace Persister with SessionPersister for v2::Receiver #750.
• Started breaking out sender-side work, beginning with Sender Session Events #777.

Artur

• Working on issue Input weight prediction for P2WSH inputs #659 to improve weight estimation for p2wsh inputs, which Liana spends.
• Opened Add expected_weight field to InputPair #772 and looking for review or ACK on the approach.
• Hoping Shing and Spacebear can review it as well.

Ben

• Last week: finished send/receive test coverage in the main payjoin crate.
• This week: focusing on Dart UniFFI integration tests.
• Skipping Python v2→v1 test coverage for now since it's cumbersome.
• Still in exploration mode; unclear what blockers might come up.
• Found a mutation in process_response within the v1 context. Trying to hide wallet fingerprints by reordering outputs, but an output-checking method is failing. Planning a follow-up issue.

Dan

• Last week: reviewed SEL changes.
• Updated [payjoin.org](https://payjoin.org) to reflect BIP77.
• Handled nonprofit operational tasks.
• Continued doing reviews.

Nothingmuch

• Spent last week writing and posting a monorepo discussion.

• Working on removing the Redis dependency; justification is posted in a https://github.com/orgs/payjoin/discussions/774.

• Set up a GCP account for test deployments.

• Building out the ACME client next.

• Looking for ACKs on discussion threads.

• Open question: what replaces Redis?

  • Answer: an in-memory hash map. Rough math suggests it’s good enough and allows bundling everything into a single binary with no external dependencies.

Spacebear

• Splitting time: ~60% on PR reviews, ~40% on Dart UniFFI bindings.
• Found a somewhat maintained Dart UniFFI binding lib.
• Talked to the maintainer and he’s answered questions and is open to updating the lib to UniFFI 0.28.
• Forked the lib and brought it up to UniFFI 0.29 last week.
• It compiles, but we haven’t verified that the generated Dart code is correct.
• This week’s focus: write Dart unit tests for Payjoin.

Shehu

• First time on the call. Looking for a good starter issue.