## Summary
- rename the FRAME alias for `pallet_evm` from `Evm` to `EVM` across the
mainnet, stagenet, and testnet runtimes
- adjust benchmarks, configuration modules, genesis builders, and
runtime tests to rely on the new alias
- keep precompile genesis setup and proxy/precompile tests aligned with
the updated names
## Context
Frontier’s `StorageOverrideHandler` (see
`fc_storage::StorageQuerier::account_code`) reads contract bytecode from
`pallet_evm::AccountCodes` using the constant `PALLET_EVM = b"EVM"` to
build the storage key:
`twox_128("EVM") ++ twox_128("AccountCodes") ++ …`
Our runtimes exported `pallet_evm` as `Evm`, so substrate stored
bytecode under the *camel-cased* prefix (`twox_128("Evm")`). Every call
that ultimately hits the storage override—including `eth_getCode`,
`eth_call`, and state queries during replay—therefore failed to locate
code for *any* account (deployed contracts and precompiles alike).
Renaming the alias to `EVM` realigns the storage prefix with Frontier’s
expectations so the override layers can pull bytecode correctly.
## Testing
- `cargo check -p datahaven-node`
- `cargo build --release -p datahaven-node`
- `eth_getCode 0x0000000000000000000000000000000000000802` → returns
`0x60006000fd`
## Storage Migration
Renaming a pallet alias changes the storage prefix for all pallet data.
Without migration, existing EVM data (smart contracts, account codes,
storage) would become inaccessible.
**Migration details:**
- **Type**: Multi-Block Migration (MBM)
- **Storage migrated**: `AccountCodes`, `AccountCodesMetadata`,
`AccountStorages`
- **Migration ID**: `datahaven-evm-mbm` (version 0 → 1)
**Testing the migration:**
```bash
# Build runtime with try-runtime
cargo build --release --features try-runtime -p
datahaven-stagenet-runtime
# Test against stagenet
try-runtime \
--runtime
./target/release/wbuild/datahaven-stagenet-runtime/datahaven_stagenet_runtime.wasm
\
on-runtime-upgrade \
--blocktime 6000 \
--checks all \
--disable-spec-version-check \
live --uri wss://dh-validator-0.datahaven-kt.xyz
```
Test results from stagenet:
- ✅ Migration completes in 1 block
- ✅ PoV size: ~5.3 KB
- ✅ Weight consumption: <0.1% of block capacity
- ✅ All 39 keys successfully migrated
## ⚠️ Breaking Changes ⚠️
If you are manually computing storage keys for the EVM pallet (e.g., directly querying chain state), you must update your code to use the new storage prefix:
- Old prefix: twox128("Evm") = 0x8b90cb...
- New prefix: twox128("EVM") = 0x6a5e91...
All EVM-facing interfaces remain unchanged.
