File blockchain_header gets corrupted

[swat69]

Electrum version v4 alpha2 : #https://github.com/vergecurrency/electrum/commit/a53a8dbe01303a36c0c22d228e90207041bf055f

after a few minutes, the run_electrum ls logging this error in the console and the connection is lost to the server:

E/i | interface.[electrum.marpmedev.xyz:50002] | Exception in wrapper_func: TypeError("unsupported operand type(s) for -: 'int' and 'str'",) Traceback (most recent call last): File "/home/ben/electrum2/electrum/util.py", line 988, in wrapper return await func(*args, kwargs) File "/home/ben/electrum2/electrum/interface.py", line 334, in wrapper_func return await func(self, *args, *kwargs) File "/home/ben/electrum2/electrum/interface.py", line 358, in run await self.open_session(ssl_context) File "/home/ben/electrum2/electrum/interface.py", line 465, in open_session await group.spawn(self.monitor_connection) File "/home/ben/.local/lib/python3.6/site-packages/aiorpcx/curio.py", line 242, in aexit await self.join() File "/home/ben/.local/lib/python3.6/site-packages/aiorpcx/curio.py", line 211, in join raise task.exception() File "/home/ben/electrum2/electrum/interface.py", line 502, in run_fetch_blocks await self._process_header_at_tip() File "/home/ben/electrum2/electrum/interface.py", line 514, in _process_header_attip , height = await self.step(height, header) File "/home/ben/electrum2/electrum/interface.py", line 572, in step return await self._resolve_potential_chain_fork_given_forkpoint(good, bad, bad_header) File "/home/ben/electrum2/electrum/interface.py", line 622, in _resolve_potential_chain_fork_given_forkpoint b = forkfun(bad_header) # type: Blockchain File "/home/ben/electrum2/electrum/blockchain.py", line 264, in fork self.save_header(header) File "/home/ben/electrum2/electrum/blockchain.py", line 188, in func_wrapper return func(self, args, kwargs) File "/home/ben/electrum2/electrum/blockchain.py", line 447, in save_header self.swap_with_parent() File "/home/ben/electrum2/electrum/blockchain.py", line 357, in swap_with_parent if not self._swap_with_parent(): File "/home/ben/electrum2/electrum/blockchain.py", line 375, in _swap_with_parent if self.parent.get_chainwork() >= self.get_chainwork(): File "/home/ben/electrum2/electrum/blockchain.py", line 188, in func_wrapper return func(self, args, kwargs) File "/home/ben/electrum2/electrum/blockchain.py", line 565, in get_chainwork work_in_single_header = self.chainwork_of_header_at_height(cached_height) File "/home/ben/electrum2/electrum/blockchain.py", line 544, in chainwork_of_header_at_height work = ((2 256 - target - 1) // (target + 1)) + 1 TypeError: unsupported operand type(s) for -: 'int' and 'str' E/i | interface.[electrum.marpmedev.xyz:50002] | Exception in wrapper_func: AssertionError((0, 1),) Traceback (most recent call last): File "/home/ben/electrum2/electrum/util.py", line 988, in wrapper return await func(args, kwargs) File "/home/ben/electrum2/electrum/interface.py", line 334, in wrapper_func return await func(self, *args, *kwargs) File "/home/ben/electrum2/electrum/interface.py", line 358, in run await self.open_session(ssl_context) File "/home/ben/electrum2/electrum/interface.py", line 465, in open_session await group.spawn(self.monitor_connection) File "/home/ben/.local/lib/python3.6/site-packages/aiorpcx/curio.py", line 242, in aexit await self.join() File "/home/ben/.local/lib/python3.6/site-packages/aiorpcx/curio.py", line 211, in join raise task.exception() File "/home/ben/electrum2/electrum/interface.py", line 502, in run_fetch_blocks await self._process_header_at_tip() File "/home/ben/electrum2/electrum/interface.py", line 514, in _process_header_attip , height = await self.step(height, header) File "/home/ben/electrum2/electrum/interface.py", line 572, in step return await self._resolve_potential_chain_fork_given_forkpoint(good, bad, bad_header) File "/home/ben/electrum2/electrum/interface.py", line 622, in _resolve_potential_chain_fork_given_forkpoint b = forkfun(bad_header) # type: Blockchain File "/home/ben/electrum2/electrum/blockchain.py", line 264, in fork self.save_header(header) File "/home/ben/electrum2/electrum/blockchain.py", line 188, in func_wrapper return func(self, args, kwargs) File "/home/ben/electrum2/electrum/blockchain.py", line 444, in save_header assert delta == self.size(), (delta, self.size()) AssertionError: (0, 1)

After deleting the file blockchain header the client is able to connect again until the error occurs again, the issue is reproducible.

[marpme]

do you have old data inside your electrum folder? if so can you still reproduce with everything disabled

I was not able to reproduce with the latest master. Could you please try again

[swat69]

no old data in folder .electrum-xvg.

new test with master branch: 2 seperate computer (ubuntu18 and debian10), one connected to electrum.marpmedev.xyz, one to node1.verge-electrum.com: Error after 60 min, next try (after deleting blockchain_header) it takes only 2 minutes up to the error, then 90 minutes. It looks like the error occur on both computers/wallets at the same time. I attach an invalid blockchain_header _blockchain_headers.gz

[swat69]

File "/home/ben/electrum2/electrum/blockchain.py", line 544, in chainwork_of_header_at_height work = ((2 256 - target** - 1) // (target + 1)) + 1
TypeError: unsupported operand type(s) for -: 'int' and 'str'

reason crash: variable target is str/undefined

540 def chainwork_of_header_at_height(self, height: int) -> int: ........"""work done by single header at given height""" ........ chunk_idx = height // 2016 - 1 ........ target = self.get_target(chunk_idx) ........ work = ((2 ** 256 - target - 1) // (target + 1)) + 1 ........ return work

494 def get_target(self, index: int) -> int: ........ # compute target from chunk x, used in chunk x+1 ........ if constants.net.TESTNET: ................ return 0 ........ if index == -1: ................ return MAX_TARGET ........ if index < len(self.checkpoints): ................ h, t = self.checkpoints[index] ................ return t

h,t ---> t = undefined, because of file checkpoints.json (index[0])

[ ["00000000007a5b03d0cde55844032c8c890c9e6bac0d7836aad53c9e251f301d", ""], ["0000000009076a32f65518d94c76fd3d281b86dc3185030800ea07ff8ffba559", ""],

[marpme]

Well we have to somehow adjust targeting for sure. Right now I've disabled the target checks in electrum since bitcoin got a quite easy approach to check em but we have a huge calculcation for upcoming targets and also do we have retargeting each and every block instead of once every 2016 Blocks.

Seems like a huge task to get this all done, but it's also quite necessary in order to ensure a solid working product.