* Change how RPCs eth_call and eth_estimateGas handle "Pending"
Before this PR we would return a rather confusing error when calling `eth_call` and `eth_estimateGas` with `"Pending"`, e.g.:
```
{"jsonrpc":"2.0","error":{"code":-32000,"message":"This request is not supported because your node is running with state pruning. Run with --pruning=archive."},"id":"e237678f6648ed12ff05a74933d06d17"}
```
In reality what is going on is that users often use `"Pending"` when they really mean `"Latest"` (e.g. MyCrypto…) and when the block in question is not actually pending. This changes our behaviour for these two RPC calls to fall back to `"Latest"` when the query with `"Pending"` fails.
Note that we already behave this way for many other RPCs:
- eth_call (after this PR)
- eth_estimateGas (after this PR)
- eth_getBalance
- eth_getCode
- eth_getStorageAt
Closes https://github.com/paritytech/parity-ethereum/issues/10096
* Fetch jsonrpc from git
* No real need to wait for new jsonrpc
* Add tests for calling eth_call/eth_estimateGas with "Pending"
* Fix a todo, add another
* Change client.latest_state to return the best header as well so we avoid potential data races and do less work
* Impl review suggestions
* Update rpc/src/v1/impls/eth.rs
Co-Authored-By: Niklas Adolfsson <niklasadolfsson1@gmail.com>
* Review grumbles
* update docs
aefa8d5f59