MemoryMutation.HistorySeek and HistoryRange were left as
`panic("not supported")` placeholders with the correct delegation
commented out. Every sibling temporal-read method on MemoryMutation
already delegates to the backing tx — GetLatest, GetAsOf, RangeAsOf,
IndexRange, HistoryStartFrom. The two outliers just hadn't been
wired when nothing called them.

A caller appeared in PR #20485 (RCacheV2 fast path in
DerivePriorReceipts): when a serial-executor block is reached via
ExecModule.updateForkChoice, reads flow through the block overlay
(MemoryMutation). ReadReceiptCacheV2 issues a HistorySeek on the
RCacheDomain to read a receipt for a txNum strictly older than the
block being processed. That panics the executor at
execution/stagedsync/exec3_serial.go:402 via DerivePriorReceipts.

Delegating to the backing tx is correct, not a workaround:

- The overlay never writes to history / domain tables
  (grep -rnE "indexKeys|historyKey|InvertedIndexWriter|DomainBufferedWriter"
  in db/kv/membatchwithdb/ is empty). The overlay's scope is
  block-level metadata: headers, TDs, bodies, canonical hashes,
  BAL bytes (see execution/execmodule/inserters.go).
- History writes take the DomainBufferedWriter / SharedDomains path,
  which is a separate layer. Any HistorySeek routed through the
  overlay is asking for data that lives exclusively in committed
  DB state or frozen snapshot files — the base tx is authoritative.
- The commented-out line in the original code already contained the
  correct implementation.

Repro: wipe chaindata/ while retaining snapshots/ (post-Fusaka
mainnet) and restart. The first forkchoice-triggered execution
resumes mid-block (startTxIndex > 0), hits
DerivePriorReceipts -> ReadReceiptCacheV2 -> HistorySeek -> panic.

After this change the overlay forwards both calls to m.db and the
sync makes progress.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

…tx (#20624)

## Summary

- Fix a `panic(\"not supported\")` that aborts post-Fusaka mainnet sync
resumed from snapshots-only (chaindata wiped, snapshots kept).
- `MemoryMutation.HistorySeek` and `HistoryRange` were placeholders; the
correct delegation was already commented out. This PR just flips them to
delegate to the backing tx, matching every sibling temporal-read method.

## Repro

On a post-Fusaka mainnet datadir, keep `snapshots/`, wipe `chaindata/`,
and start `erigon`. The first forkchoice-triggered execution resumes
mid-block (`startTxIndex > 0`) and takes the partial-block receipt
reconstruction path added in #20452. That calls
`receipts.DerivePriorReceipts`, which on top of the RCacheV2 fast path
(#20485) issues `tx.HistorySeek(kv.RCacheDomain, …)`. When the
containing executor runs through `ExecModule.updateForkChoice`, the tx
is the block overlay (`MemoryMutation`), and `HistorySeek` panics:

```
panic: not supported

goroutine … [running]:
…/db/kv/membatchwithdb.(*MemoryMutation).HistorySeek
  .../db/kv/membatchwithdb/memory_mutation.go:872
…/db/rawdb.ReadReceiptCacheV2
  .../db/rawdb/accessors_chain.go:1276
…/execution/receipts.DerivePriorReceipts
  .../execution/receipts/derive.go:193
…/execution/stagedsync.(*serialExecutor).executeBlock.func2
  .../execution/stagedsync/exec3_serial.go:402
…
…/execution/execmodule.(*ExecModule).updateForkChoice
  .../execution/execmodule/forkchoice.go:473
```

## Why delegation is correct (not a workaround)

- Every other temporal-read method on `MemoryMutation` already delegates
to the backing tx: `GetLatest`, `GetAsOf`, `RangeAsOf`, `IndexRange`,
`HistoryStartFrom`. The two outliers just hadn't been wired.
- The block overlay never writes to history / domain tables — its scope
is block-level metadata (headers, TDs, bodies, canonical hashes, BAL
bytes, see `execution/execmodule/inserters.go`). History writes flow
through `DomainBufferedWriter` / `SharedDomains`, not through the
overlay. `grep -rnE
\"indexKeys|historyKey|InvertedIndexWriter|DomainBufferedWriter\"
db/kv/membatchwithdb/` is empty.
- Any `HistorySeek` routed through the overlay is therefore asking for
data that lives exclusively in committed DB state or frozen snapshot
files. The base tx is authoritative; the overlay has nothing to add.
- The original author even left the correct call commented out on the
same line.

## Test plan

- [x] `make lint` — 0 issues
- [x] `make erigon` — builds clean
- [x] `go test -short ./db/kv/membatchwithdb/...` — passes
- [ ] Manual: post-Fusaka mainnet, wipe `chaindata/` / keep
`snapshots/`, restart — sync now progresses past the first
forkchoice-triggered execution instead of panicking (next hit in our
testing was the unrelated stale-read bug tracked in follow-up).

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-authored-by: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
Co-authored-by: Alex Sharov <AskAlexSharov@gmail.com>