Eliminating <T>, step by step.

[longfin]

In many cases dealing with Block<T> or Transaction<T>, we don't need to know the specific type of actions (i.e., T) that the block contains since T is needed only in limited cases. (i.e., calculating the next states)

So it has been proposed to get rid of this 'T' for a long time too. But since Block<T> and Transaction<T> had already been used too much, we couldn't get our hands on them easily.

To make this easier, I suggest the following sequence:

1. Instead of excluding T from Block<T>, Transaction<T>, define new interfaces that guarantee only other necessary information (e.g., header).
2. For classes using Block<T>, and Transaction<T> (e.g., Swarm<T>), use the interface used in 1 and remove the T.
   • In this case, it is desirable to work from a class (terminal) that has no dependencies as much as possible.
3. Remove T from Block<T>, and Transaction<T>, and only explicitly assume this in classes that need it, such as ActionEvaluator.

[longfin]

(Note for future workings)

To elide T from IBlockPolicy<T>, these types there may need to be widened.

• Transaction<T> -> ITransaction
• Block<T> -> IBlock
• BlockChain<T> -> IBlockChainStates

Also, since ITransaction and .BlockAction will become to agnostic against actual types, we need to provide context info (i.e., ActionTypeLoaderContext) to activate IActions.

[riemannulus]

#3149

[OnedgeLee]

Closing, since <T> has been eliminated from Block, Transaction and classes using them.

• ♻️ Change Transaction<T> to Transaction #3121
• ♻️ Change Block<T> to Block #3123
• 🧹 Remove <T> from IRenderer<T> and all its implementations #3163
• 🧹 Remove <T> from BlockChain<T> #3182
• 🧹 Remove <T> from Context<T> and ConsensusContext<T> #3183
• 🧹 Remove <T> from Swarm<T> #3184
• 🧹 Remove <T> from Libplanet.Explorer #3185
• 🧹 Remove PolymorphicAction<T> #3193