Fix mempool transactions disappearing if a parent tx is confirmed.

[Dirbaio]

There's a bug in the logic that processes new blocks that causes txs to be unnecessarily dropped from mempool.

Basically:

There are two txs A and B in mempool. Tx B uses an output from A.
A new block is received that contains A but not B.

RemoveTransaction(A) will be called on the mempool, which will recursively remove B. However, B should not be removed because it's not orphan, its parent is now on the blockchain.

This fixes the bug by not recursively removing depending transactions when processing blocks.

[dajohi]

I much rather prefer RemoveTransaction get the API change like removeTransaction, and get rid of RemoveConfirmedTransaction. The update all callers of RemoveTransaction() to specify whether they want to remove depending or not.

[davecgh]

The concept is correct, but I agree with @dajohi regarding the implementation.

[davecgh]

Reviewed 2 of 2 files at r1, 2 of 2 files at r2.
Review status: all files reviewed at latest revision, all discussions resolved.

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Comments from the review on Reviewable.io

[dajohi]

OK

[davecgh]

OK

[jrick]

Not sure depending is the best name for those transactions, because depending could also refer to parent txs. Perhaps removeChildren?

[davecgh]

I suppose the name could be confusing. Given the comment accurately describes it I didn't worry about it, but perhaps removeRedeemers or removeChildren might be less confusing.

[jrick]

+1 for removeRedeemers

[Dirbaio]

Changed.

[davecgh]

Reviewed 1 of 1 files at r3.
Review status: all files reviewed at latest revision, all discussions resolved.

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Comments from the review on Reviewable.io

[jrick]

ok

[dajohi]

While here, can we make the above comment limited to 80 chars?

[Dirbaio]

Review status: 1 of 2 files reviewed at latest revision, 1 unresolved discussion.

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^{blockmanager.go, line 1219 [r3] (raw file):}
Done.

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Comments from the review on Reviewable.io

[davecgh]

Reviewed 1 of 1 files at r4.
Review status: all files reviewed at latest revision, 1 unresolved discussion.

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Comments from the review on Reviewable.io

[dajohi]

OK