[Chore] Guard against nil buckets to prevent panics

[zquestz]

Just adds checks to make sure a bucket is returned in our indexers. That way if we have an issue with a nil bucket, it will throw an error and not panic! The buckets should always be present, so returning an error is correct.

Mitigates #472

[zquestz]

You call a function that needs the txindex.On May 21, 2021 2:02 PM, James Cramer ***@***.***> wrote: Slp index works without txindex, iirc. I'll have to double check. —You are receiving this because you authored the thread.Reply to this email directly, view it on GitHub, or unsubscribe.

[jcramer]

You call a function that needs the txindex on.

Since s.slpIndex.GraphSearchEnabled() is checked prior to calling s.fetchTransactionFromBlock(txnHash), s.txIndex must be enabled. GS requires txindex.

Even if txIndex is disabled we need this method to run because the call to isSlpValid := s.checkSlpTxOnEvent(txDesc.Tx.MsgTx(), "mempool") allows mempool txns to have slp validity performed.