Fix unresumable Sender

[DanGould]

The Sender was generating new hpke keys on resume since keygen was being done in extract_v2. This caused a problem where when the Sender was persisted, stopped, and resumed, the receiver would have already pushed a response to a different ShortId than the one the Sender would look for it in the resumed state.

By generating a key on Sender creation and persisting that the Sender can produce a consistent HpkeContext every single run.

I am NOT sure why the e2e test did not catch this. I believed its behavior was starting a receiver, stopping it, starting a sender, stopping it, resuiming a receiver, stopping it, and resuming a sender, and stopping it which is where this bug propagated. It didn't fail before this change and I'm not sure why, it should have.

[coveralls]

Pull Request Test Coverage Report for Build 12465664083

Details

• 10 of 10 (100.0%) changed or added relevant lines in 2 files are covered.
• 252 unchanged lines in 8 files lost coverage.
• Overall coverage decreased (-5.3%) to 61.852%

---

Files with Coverage Reduction	New Missed Lines	%
payjoin-directory/src/lib.rs	4	79.19%
payjoin-directory/src/db.rs	4	89.55%
payjoin-cli/src/db/mod.rs	4	0.0%
payjoin-cli/src/db/v2.rs	6	0.0%
payjoin-cli/src/app/mod.rs	15	0.0%
payjoin-cli/src/app/config.rs	54	0.0%
payjoin-cli/src/app/v2.rs	64	0.0%
payjoin-cli/src/main.rs	101	0.0%

Totals
Change from base Build 12425801101:	-5.3%
Covered Lines:	2899
Relevant Lines:	4687

---

💛 - Coveralls

[spacebear21]

It looks like the e2e test is silently swallowing errors somehow. This is in master:

running 1 test
Using OHTTP Keys from config
Receive session established
Request Payjoin by sharing this Payjoin Uri:
bitcoin:bcrt1q520j8a7zh4xg58eajj25ccwpq98x8u9d70ahcy?amount=0.00054321&pjos=0&pj=HTTPS://LOCALHOST:53404/QE3WD63UC0FT2%23RK1QWWGRLNPZX7FCW0PGNNZ2TR5PUE6FQ6GJTRPKMXAW6UKQF83Q9XAK+OH1QYPW96LWVYX0EYRKPN39CK87N6SHUL6WTLATYZXC977WHTSLZ3P2RSS+EX1CX9K5EC
Posting Original PSBT Payload request...
Sent fallback transaction
No response yet.
resume
Receive session established
Request Payjoin by sharing this Payjoin Uri:
bitcoin:bcrt1q520j8a7zh4xg58eajj25ccwpq98x8u9d70ahcy?pjos=0&pj=HTTPS://LOCALHOST:53404/QE3WD63UC0FT2%23RK1QWWGRLNPZX7FCW0PGNNZ2TR5PUE6FQ6GJTRPKMXAW6UKQF83Q9XAK+OH1QYPW96LWVYX0EYRKPN39CK87N6SHUL6WTLATYZXC977WHTSLZ3P2RSS+EX1CX9K5EC
Polling receive request...
Fallback transaction received. Consider broadcasting this to get paid if the Payjoin fails:
02000000000101e195c1d2d1d490fa9682259c2096929ef4977440e0c9f3fa184febd19d7ecb830000000000feffffff0231d4000000000000160014a29f23f7c2bd4c8a1f3d94954c61c1014e63f0ad421d052a01000000160014291e848a3f81099b9dabba25a5802f1f004765810247304402204010bc2326ffa93982a7ac686190b8f55fed7d00347c9b9b6427a8a43d8d28a202206d697191848fc2f6e81707335b59a86b5b8a66db1afec3b5aa51aee0f10f8d26012103293e88f418349f2f2fc2cca489deeb1c7afcd5e01e1466610f6e816d5e5763c100000000
Got a request from the sender. Responding with a Payjoin proposal.
Response successful. Watch mempool for successful Payjoin. TXID: d6e44b930408afbc553c370b85a81866b5d930e4e2ddf5d6ca310a8218f29f03
Posting Original PSBT Payload request...
Sent fallback transaction
No response yet.
No response yet.
No response yet.
No response yet.
The receiver sent an invalid response.
Error: The receiver sent an invalid response.

Caused by:
    Response error
test e2e::send_receive_payjoin ... ok

test result: ok. 1 passed; 0 failed; 0 ignored; 0 measured; 0 filtered out; finished in 16.76s

[spacebear21]

tACK 226816a

[spacebear21]

I pushed a fix for the e2e test to correctly bubble up payjoin-cli errors, and confirmed that this commit currently fails on master.

[DanGould]

Also tested 86a9a8a cherry-picked on top of master to make sure it fails. good catch.