[FEAT] Amountless Melt Requests

[cloudsupper]

Main Objective

Adds support for amountless payment requests (e.g. bolt11 amountless invoices) and signals support in the info endpoint (mint features)

https://github.com/cashubtc/nuts/pull/173

Enabled for:

• [x] CLN
• [x] LND
• [x] Fake
• [ ] Blink
• [ ] LNbits
• [ ] Strike

Also Added

PaymentQuoteKind:

• REGULAR for regular quotes
• AMOUNTLESS for quotes where the amount is specified in the amountless option
• PARTIAL for quotes where we pay only the partial amount specified in the mpp option

m07_add_payment_quote_kind migration adds the kind column to melt_quotes in the DB. Defaults to REGULAR for all already present records.

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 27.17949% with 142 lines in your changes missing coverage. Please review.

Project coverage is 52.50%. Comparing base (3e32dc4) to head (5e4aac8). Report is 3 commits behind head on main.

Files with missing lines	Patch %	Lines
cashu/lightning/clnrest.py	7.89%	35 Missing :warning:
cashu/lightning/lnd_grpc/lnd_grpc.py	8.57%	32 Missing :warning:
cashu/lightning/lndrest.py	8.57%	32 Missing :warning:
cashu/lightning/fake.py	15.00%	17 Missing :warning:
cashu/core/mint_info.py	18.18%	9 Missing :warning:
cashu/wallet/wallet.py	25.00%	6 Missing :warning:
cashu/wallet/v1_api.py	25.00%	3 Missing :warning:
cashu/core/errors.py	81.81%	2 Missing :warning:
cashu/mint/ledger.py	50.00%	2 Missing :warning:
cashu/core/models.py	90.00%	1 Missing :warning:
... and 3 more

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #712      +/-   ##
==========================================
- Coverage   55.36%   52.50%   -2.86%     
==========================================
  Files          84       84              
  Lines        9479     9652     +173     
==========================================
- Hits         5248     5068     -180     
- Misses       4231     4584     +353     

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[cloudsupper]

There is a problem here: when paying, backends cannot distinguish whether the amount on the quote is a partial amount or the full amount for a amountless invoice.

[cloudsupper]

It seems like the tests with fakewallet have nuts = {} empty nuts dict (?)

EDIT: problem was the deprecated API CI workflow

[callebtc]

Getting back to this very nice PR.

I think it could benefit from a few more test cases:

• error if an amountless invoice is trying to be paid without providing an amount (should maybe be a mint test, not wallet?)
• and the opposite, error when a normal invoice is being paid but with an amount provided in the request
• tests for the wallet cli for paying amountless invoices

[cloudsupper]

Getting back to this very nice PR.

I think it could benefit from a few more test cases:

* error if an amountless invoice is trying to be paid without providing an amount (should maybe be a mint test, not wallet?)

* and the opposite, error when a normal invoice is being paid but with an amount provided in the request

* tests for the wallet cli for paying amountless invoices

Yea actually it's testing the Mint, not the wallet. I should probably move that particular test somewhere else.

[cloudsupper]

and the opposite, error when a normal invoice is being paid but with an amount provided in the request

We have MPP quotes remember? A client can specify the amount in the request even if the invoice specifies one.