"eth_chainId" sometimes returns 0x0 instead of the correct chainId

[nicinuse]

Hi there,

I am trying to set up a chainlinnk node with latest stable geth client, but it fails vecause of missing chainId value.

System information

Geth version:

Geth
Version: 1.9.12-stable
Git Commit: b6f1c8dcc058a936955eb8e5766e2962218924bc
Git Commit Date: 20200316
Architecture: amd64
Protocol Versions: [65 64 63]
Go Version: go1.13.8
Operating System: linux
GOPATH=
GOROOT=/usr/local/go

OS & Version:

Alpine Linux
```
Commit hash : (if `develop`)

#### Expected behaviour
Return the correct chainId


#### Actual behaviour
ChainId is always "0x0" (not available)


#### Steps to reproduce the behaviour
Run geth with
```
geth --testnet --nousb --rpc --rpcaddr '0.0.0.0' --rpcvhosts '*' --rpccorsdomain '*'
```
Ask for chainId
```
curl -k -X POST -H 'Content-Type: application/json' -d '{"jsonrpc":"2.0","method":"eth_chainId","id":1}' http://localhost:8545
```

[ligi]

seems to just happen for "--testnet" - got the correct results for --goerli and main net. Testnet will be deprecated soon anyway as of #20852 - but should still be fixed IMHO. Thanks for the report

[nicinuse]

Hi there,

running a geth client on main net

geth --nousb --ws
INFO [04-07|04:36:34.474] Bumping default cache on mainnet         provided=1024 updated=4096
WARN [04-07|04:36:34.474] Sanitizing cache to Go's GC limits       provided=4096 updated=1980
INFO [04-07|04:36:34.477] Maximum peer count                       ETH=50 LES=0 total=50
INFO [04-07|04:36:34.477] Smartcard socket not found, disabling    err="stat /run/pcscd/pcscd.comm: no such file or directory"
INFO [04-07|04:36:34.478] Starting peer-to-peer node               instance=Geth/v1.9.12-stable-b6f1c8dc/linux-amd64/go1.13.8
INFO [04-07|04:36:34.478] Allocated trie memory caches             clean=495.00MiB dirty=495.00MiB
INFO [04-07|04:36:34.479] Allocated cache and file handles         database=/root/.ethereum/geth/chaindata cache=990.00MiB handles=512
INFO [04-07|04:36:34.504] Opened ancient database                  database=/root/.ethereum/geth/chaindata/ancient
INFO [04-07|04:36:34.504] Writing default main-net genesis block
INFO [04-07|04:36:34.801] Persisted trie from memory database      nodes=12356 size=1.78MiB time=77.057798ms gcnodes=0 gcsize=0.00B gctime=0s livenodes=1 livesize=0.00B
INFO [04-07|04:36:34.801] Initialised chain configuration          config="{ChainID: 1 Homestead: 1150000 DAO: 1920000 DAOSupport: true EIP150: 2463000 EIP155: 2675000 EIP158: 2675000 Byzantium: 4370000 Constantinople: 7280000 Petersb
urg: 7280000 Istanbul: 9069000, Muir Glacier: 9200000, Engine: ethash}"

and trying to get the network id via ws api request returns "0x0" too.

wscat -c localhost:8546
Connected (press CTRL+C to quit)
> {"jsonrpc":"2.0","method":"eth_chainId","id":1}
< {"jsonrpc":"2.0","id":1,"result":"0x0"}

[ligi]

hm - very strange - for mainnet I get the correct result:

> {"jsonrpc":"2.0","method":"eth_chainId","id":1}
< {"jsonrpc":"2.0","id":1,"result":"0x1"}

[tyrion70]

Having no issues here on Ropsten either, @nicinuse could it be that your chain hasn't synced completely yet? If you try this on an unsynced chain you get the 0x0 result (not sure if thats correct behaviour @ligi though). Once the chain is synced it will give the right value.

[ligi]

for me it is also working when it is still syncing:

> {"jsonrpc":"2.0","method":"eth_syncing","id":1}
< {"jsonrpc":"2.0","id":1,"result":{"currentBlock":"0x3b927b","highestBlock":"0x8a61c9","knownStates":"0x0","pulledStates":"0x0","startingBlock":"0x3e2fc5"}}

> {"jsonrpc":"2.0","method":"eth_chainId","id":1}
< {"jsonrpc":"2.0","id":1,"result":"0x1"}

there must be something else to it. But I would also expect to give the correct result when it is still syncing.

[q9f]

seems to just happen for "--testnet" - got the correct results for --goerli and main net.

does it also happen for --ropsten? I'm ahead of time 🤣

[ligi]

wasn't the "--ropsten" just included by your PR? Did not try it on top of this - but also do not see why this would be the reason.

[MariusVanDerWijden]

For me it works only for the --goerli testnet.

command	output
geth --nousb --ws	< {"jsonrpc":"2.0","id":1,"result":"0x0"}
geth --nousb --ws --rinkeby	< {"jsonrpc":"2.0","id":1,"result":"0x0"}
geth --nousb --ws --testnet	< {"jsonrpc":"2.0","id":1,"result":"0x0"}
geth --nousb --ws --goerli	< {"jsonrpc":"2.0","id":1,"result":"0x5"}

[ligi]

The PR implementing this feature: https://github.com/ethereum/go-ethereum/pull/19694/files

[ligi]

currently it depends on the sync state - but IMHO it should just take the value from the config

[karalabe]

#17617