The total difficulty is the sum of all block difficulties from genesis
to a certain block. This value was used in PoW for deciding which chain
is heavier, and thus which chain to select. Since PoS has a different
fork selection algorithm, all blocks since the merge have a difficulty
of 0, and all total difficulties are the same for the past 2 years.
Whilst the TDs are mostly useless nowadays, there was never really a
reason to mess around removing them since they are so tiny. This
reasoning changes when we go down the path of pruned chain history. In
order to reconstruct any TD, we **must** retrieve all the headers from
chain head to genesis and then iterate all the difficulties to compute
the TD.
In a world where we completely prune past chain segments (bodies,
receipts, headers), it is not possible to reconstruct the TD at all. In
a world where we still keep chain headers and prune only the rest,
reconstructing it possible as long as we process (or download) the chain
forward from genesis, but trying to snap sync the head first and
backfill later hits the same issue, the TD becomes impossible to
calculate until genesis is backfilled.
All in all, the TD is a messy out-of-state, out-of-consensus computed
field that is overall useless nowadays, but code relying on it forces
the client into certain modes of operation and prevents other modes or
other optimizations. This PR completely nukes out the TD from the node.
It doesn't compute it, it doesn't operate on it, it's as if it didn't
even exist.
Caveats:
- Whenever we have APIs that return TD (devp2p handshake, tracer, etc.)
we return a TD of 0.
- For era files, we recompute the TD during export time (fairly quick)
to retain the format content.
- It is not possible to "verify" the merge point (i.e. with TD gone, TTD
is useless). Since we're not verifying PoW any more, just blindly trust
it, not verifying but blindly trusting the many year old merge point
seems just the same trust model.
- Our tests still need to be able to generate pre and post merge blocks,
so they need a new way to split the merge without TTD. The PR introduces
a settable ttdBlock field on the consensus object which is used by tests
as the block where originally the TTD happened. This is not needed for
live nodes, we never want to generate old blocks.
- One merge transition consensus test was disabled. With a
non-operational TD, testing how the client reacts to TTD is useless, it
cannot react.
Questions:
- Should we also drop total terminal difficulty from the genesis json?
It's a number we cannot react on any more, so maybe it would be cleaner
to get rid of even more concepts.
---------
Co-authored-by: Gary Rong <garyrong0905@gmail.com>
This PR extends the Hooks interface with a new method,
`OnSystemCallStartV2`, which takes `VMContext` as its parameter.
Motivation
By including `VMContext` as a parameter, the `OnSystemCallStartV2` hook
achieves parity with the `OnTxStart` hook in terms of provided insights.
This alignment simplifies the inner tracer logic, enabling consistent
handling of state changes and internal calls within the same framework.
---------
Co-authored-by: Sina Mahmoodi <itz.s1na@gmail.com>
This change relocates the EVM tx context switching to the ApplyMessage function.
With this change, we can remove a lot of EVM.SetTxContext calls before
message execution.
### Tracing API changes
- This PR replaces the `GasPrice` field of the `VMContext` struct with
`BaseFee`. Users may instead take the effective gas price from
`tx.EffectiveGasTipValue(env.BaseFee)`.
---------
Co-authored-by: Sina Mahmoodi <itz.s1na@gmail.com>
Breaking changes:
- The ChainConfig was exposed to tracers via VMContext passed in
`OnTxStart`. This is unnecessary specially looking through the lens of
live tracers as chain config remains the same throughout the lifetime of
the program. It was there so that native API-invoked tracers could
access it. So instead we moved it to the constructor of API tracers.
Non-breaking:
- Change the default config of the tracers to be `{}` instead of nil.
This way an extra nil check can be avoided.
Refactoring:
- Rename `supply` struct to `supplyTracer`.
- Un-export some hook definitions.
Extends the opcontext interface to include accessor for code being executed in current context. While it is possible to get the code via `statedb.GetCode`, that approach doesn't work for initcode.
Add changes from #30409 and #29338 to changelog.
---------
Co-authored-by: Martin HS <martin@swende.se>
Co-authored-by: Guillaume Ballet <3272758+gballet@users.noreply.github.com>
Introduces the first built-in live tracer. The supply tracer tracks ETH supply changes across blocks
and writes the output to disk. This will need to be enabled through CLI using the `--vmtrace supply` flag.
Co-authored-by: Sina Mahmoodi <itz.s1na@gmail.com>
Added a start/end system where tracer can be notified that processing of some Ethereum system calls is starting processing and also notifies it when the processing has completed.
Doing a start/end for system call will enable tracers to "route" incoming next tracing events to go to a separate bucket than other EVM calls. Those not interested by this fact can simply avoid registering the hooks.
The EVM call is going to be traced normally afterward between the signals provided by those 2 new hooks but outside of a transaction context OnTxStart/End. That something implementors of live tracers will need to be aware of (since only "trx tracers" are not concerned by ProcessBeaconRoot).
---------
Co-authored-by: Sina Mahmoodi <itz.s1na@gmail.com>
Here we add a Go API for running tracing plugins within the main block import process.
As an advanced user of geth, you can now create a Go file in eth/tracers/live/, and within
that file register your custom tracer implementation. Then recompile geth and select your tracer
on the command line. Hooks defined in the tracer will run whenever a block is processed.
The hook system is defined in package core/tracing. It uses a struct with callbacks, instead of
requiring an interface, for several reasons:
- We plan to keep this API stable long-term. The core/tracing hook API does not depend on
on deep geth internals.
- There are a lot of hooks, and tracers will only need some of them. Using a struct allows you
to implement only the hooks you want to actually use.
All existing tracers in eth/tracers/native have been rewritten to use the new hook system.
This change breaks compatibility with the vm.EVMLogger interface that we used to have.
If you are a user of vm.EVMLogger, please migrate to core/tracing, and sorry for breaking
your stuff. But we just couldn't have both the old and new tracing APIs coexist in the EVM.
---------
Co-authored-by: Matthieu Vachon <matthieu.o.vachon@gmail.com>
Co-authored-by: Delweng <delweng@gmail.com>
Co-authored-by: Martin HS <martin@swende.se>
Péter Szilágyi
Matthieu Vachon
georgehao
Nebojsa Urosevic
rjl493456442
Sina M
Karol Chojnowski
Ikko Ashimine
Guillaume Ballet
jwasinger
Chris Ziogas