fix: prevent GetStorageRoot from polluting contract cache and causing incorrect state writeback

[envestcc]

Problem

When validating historical blocks, a "delta state digest doesn't match" error occurs. The root cause is that
the geth upgrade (v1.7.4-0.20260114032628) introduced a GetStorageRoot(address) call in evm.create() for
contract creation collision detection. The previous GetStorageRoot implementation called
getContractWoCreate, which created a contract trie and added the target account to cachedContract — even
for non-contract (EOA) accounts.

This triggered the following chain of events:

1. GetStorageRoot(addr) → getContractWoCreate(addr) → account added to cachedContract
2. EVM calls Snapshot() → iterates all cached contracts → computes trie.RootHash() for the empty storage
   trie → writes non-zero hash to Account.Root on the original contract object
3. CommitContracts() writes back all cached contracts via PutState, including this unmodified account
   with a now non-zero Root

In v2.3.3 (old geth), GetStorageRoot did not exist, so the account was never cached and its Root stayed
zero.

Fix

Commit 1: Fix GetStorageRoot (immediate fix)

Modified GetStorageRoot to read the account's Root field directly via accountutil.Recorded without
creating a contract trie or adding to cachedContract. Removed the now-dead getContractWoCreate function.

Commit 2: Skip writing read-only contracts (forward-looking hardening)

Added AlwaysWriteCachedContract feature flag (gated by ToBeEnabled fork height). When disabled (after
fork activation), CommitContracts skips both Commit() and PutState() for contracts that were only read
(not modified by SetState/SetCode). This prevents any future read operation from inadvertently causing
state writes through the cachedContract → Snapshot → CommitContracts chain.

• Added Dirty() method to Contract interface to check dirtyCode || dirtyState
• Before fork: old behavior preserved (write all cached contracts)
• After fork: only dirty contracts are committed and written back

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud