Composer V2

[ouziel-slama]

• Replacement of transaction.py and transaction_helper/* with composer.py
• No more dependency on Addrindexrs, prioritizing the use of Bitcoin Core to retrieve UTXOs or search for a public key, and then with Electr if it is configured.
• Use of the bitcoin-utils library to generate transactions
• API backward compatible with the old composer
• Addition of the following parameters:
  • change_address: allows defining the change address
  • more_outputs: allows adding an arbitrary number of outputs in the form <value>:<address> or <value>:<script_pubkey>
  • use_all_inputs_set: forces the use of all UTXOs provided with inputs_set
  • sat_per_vbyte: allows defining transaction fees
  • max_fee: defines the maximum fees to be paid
  • verbose: includes transaction details, notably data and psbt
  • multisig_pubkey: public key allowing the redemption of multisig data outputs
• The following parameters are deprecated but still work: fee_per_kb, fee_provided, dust_return_pubkey, return_psbt, regular_dust_size, multisig_dust_size, extended_tx_info, old_style_api, p2sh_pretx_txid, segwit, unspent_tx_hash
• Composed transactions no longer contain the script_pubkey (lock script) where the script_sig (unlock script) should be.
• With verbose=true, the composer also returns a lock_scripts field that contains the script_pubkey of the UTXOs used by the transaction.
• Composed transactions use a version byte 2 instead of version 1
• Error messages for UTXOs now contain the reason for the error in parentheses: invalid UTXOs: <utxo(s)> (<reason>)

---

• Double-check the spelling and grammar of all strings, code comments, etc.
• Double-check that all code is deterministic that needs to be
• Add tests to cover any new or revised logic
• Ensure that the test suite passes
• Update the project release notes
• Update the project documentation, as appropriate, with a corresponding Pull Request in the Documentation repository

[adamkrellenstein]

beautiful! super clean!

[adamkrellenstein]

So I think we're going to be removing P2SH encoding soon-ish (once we add support for encoding in witness data). In the meantime, we can re-enable this? Will reduce fees for some users.