feat: Add exclude_unconfirmed and exclude_below_confirmations

[evanlinjin]

Fixes #143

Description

These are convenience methods on TxBuilder that can be used to filter out outpoints which do not meet a given confirmation threshold.

Previously, I advocated a feature freeze on TxBuilder, but I believe we can make an exception for these helper methods, as they do not broaden the TxBuilder interface’s error surface. Going forward, all other development should be directed to the bdk-tx repository and crate.

cc. @tnull

Changelog notice

Added:
- `TxBuilder::exclude_unconfirmed`
- `TxBuilder::exclude_below_confirmations`

Checklists

All Submissions:

• I've signed all my commits
• I followed the contribution guidelines
• I ran cargo +nightly fmt and cargo clippy before committing

New Features:

• I've added tests for the new feature
• I've added docs for the new feature

[coveralls]

Pull Request Test Coverage Report for Build 15892909684

Details

• 92 of 95 (96.84%) changed or added relevant lines in 1 file are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+0.1%) to 85.673%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
wallet/src/wallet/tx_builder.rs	92	95	96.84%

Totals
Change from base Build 15719064446:	0.1%
Covered Lines:	7469
Relevant Lines:	8718

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💛 - Coveralls

[ValuedMammal]

Looks good. I was a bit confused by the comment that refers to the exclude_unbroadcasted() method which is not actually defined anywhere.

[nymius]

suggestion(doc):

min_confirms is the minimum number of confirmations a transaction must have in order for its outpoints to be available for spend in the next block/available for selection in the current one.

[evanlinjin]

@nymius could you highlight for me what detail you think is missing in the original docs?

[nymius]

As you were using the same logic that the coinbase maturity check

.map_or(0, |h| tip_height.saturating_add(1).saturating_sub(h))

And the definition wasn't clear previously, I thought it was good to emphasize what spendable means: the outpoint is available for selection in the current block.

If you are expecting to make a transaction with a UTXO mined 4 blocks before, and you use exclude_below_confirmations with min_confirms = 4 you should know that same UTXO will be available for selection.

But don't consider it a blocker, if you think is not worth it.

[oleonardolima]

utACK 5a65422

I agree with nymius's comments, but I also don't see it as a blocker.

[notmandatory]

ACK 5a65422

[ValuedMammal]

ACK 5a65422