`assimilate_storage` not implemented for `ChainSpec`

Question

I have a slightly custom chain spec that makes regular chain spec serializable with serde to/from JSON.

In the impl of sp_runtime::BuildStorage I just forward assimilate_storage call to the underlying chain spec:

impl<GenesisConfig, Extensions> BuildStorage for SerializableChainSpec<GenesisConfig, Extensions>
where
    GenesisConfig: RuntimeGenesis,
{
    fn assimilate_storage(&self, storage: &mut Storage) -> Result<(), String> {
        self.chain_spec.assimilate_storage(storage)
    }
}

This worked great until I tried to run benchmarks, when it failed with:

Error: SubstrateCli(Input("`assimilate_storage` not implemented for `ChainSpec`."))

Not 100% sure what this means and what implementation should have looked like instead, any suggestions?

Answer 1

The implementation of BuildStorage for ChainSpec was implementing assimilate_storage by returning the error you mentioned. It seems that back in the days I didn't implemented this function properly, but don't ask me why...

Nevertheless, after this pr it will be fixed.