This commit modifies the way initial database creation is handled.
Previously, the genesis for the main chain was inserted automatically upon
creation of the database. However, that approach caused an issue since
other networks such as the test network don't use the same genesis block
as the main network.
The new approach introduced by this commit is to leave it up to the caller
to insert the desired genesis block. In order to support this, the
InsertBlock function has been modified to allow the first (and only the
first) block to be inserted without having an existing parent. Also, the
NewestSha function has been modified to return a zero hash, -1 for the
height, and no error when the database does not yet have any blocks. This
allows the caller to determine the difference between no blocks and only
the genesis block (in which case the return values would be the genesis
hash and 0 for the height).
The go vet command complains about untagged struct initializers when
defining a ShaHash directly. This seems to be a limitation where go vet
does not exclude the warning for types which are a constant size byte array
like it does for normal constant size byte array definition.
This commit simply modifies the tests to use a constant definition cast to a
ShaHash to overcome the limitation of go vet.
This commit modifies the double spend detection to handle double spends
within the same block as well as side chains when doing the checks before
reorganizing the chain.
There was not much documentation about the difference between testnet and
testnet3, so make it clear that testnet is used for regression tests and
testnet3 is the public test network (version 3).
In addition to returning errors to the caller, log the error with a prefix
in a few key places that helps identify the origin for errors. In some
cases, the underlying error comes from a different subsystem such as the
SQL database driver and the error messages can be fairly generic.
This commit modifies the code to use params based on the active network
which paves the way for supporting the special rules and different genesis
blocks used by the test networks.
Since the same coinbase transaction is used for the genesis blocks of
all three currently supposed networks, separate it into its own var and
use a reference to it in each of the genesis block defintions.
After discussing the criteria used by the core developers on #btc-dev IRC
channel, gmaxwell indicated they like to see at least 2016 blocks. This
commit updates the checkpoint confirmations accordingly.
btcscript contains an amount of debug logging that is very useful to
have. We have agreed that testing this isn't realy practical or indeed
really useful and thus is rather unlikely to grow test coverage any time
soon.
