Fix description of --prune=r flag (#5193)

* Fix description of --prune=r flag

* Small correction

README.md

@@ -231,23 +231,7 @@ http.api : ["eth","debug","net"]
 
 ### Beacon Chain (Consensus Layer)
 
-Erigon can be used as an Execution Layer (EL) for Consensus Layer clients (CL). Default configuration is OK. CL
-relies on availability of receipts – don't prune them: don't add character `r` to `--prune` flag. However, old receipts
- are not needed for CL and you can safely prune them with `--prune htc`.
-
- ## ETH2 Deposit Contract Block Number
-
- - Mainnnet: 11052984
- - Sepolia: 1273020
- - Goerli: 4367322
-
-
- ## ETH2 Deposit Contract Address
-
- - Mainnet: 0x00000000219ab540356cBB839Cbe05303d7705Fa
- - Sepolia: 0x7f02C3E3c98b133055B8B348B2Ac625669Ed295D
- - Goerli: 0xff50ed3d0ec03aC01D4C79aAd74928BFF48a7b2b
-
+Erigon can be used as an Execution Layer (EL) for Consensus Layer clients (CL). Default configuration is OK.
 
 If your CL client is on a different device, add `--authrpc.addr 0.0.0.0` ([Engine API] listens on localhost by default)
 as well as `--authrpc.vhosts <CL host>`.

ethdb/prune/storage_mode.go

@@ -1,6 +1,7 @@
 package prune
 
 import (
+	"bytes"
 	"encoding/binary"
 	"errors"
 	"fmt"
@@ -79,10 +80,9 @@ func FromCli(chainId uint64, flags string, exactHistory, exactReceipts, exactTxI
 			}
 		}
 		mode.Receipts = Before(beforeR)
-	} else {
-		if exactReceipts == 0 && mode.Receipts.Enabled() {
-			mode.Receipts = Before(pruneBlockBefore)
-		}
+	} else if exactReceipts == 0 && mode.Receipts.Enabled() && pruneBlockBefore != 0 {
+		// Default --prune=r to pruning receipts before the Beacon Chain genesis
+		mode.Receipts = Before(pruneBlockBefore)
 	}
 	if beforeT > 0 {
 		mode.TxIndex = Before(beforeT)
@@ -309,6 +309,10 @@ func EnsureNotChanged(tx kv.GetPut, pruneMode Mode) (Mode, error) {
 	if pruneMode.Initialised {
 		// If storage mode is not explicitly specified, we take whatever is in the database
 		if !reflect.DeepEqual(pm, pruneMode) {
+			if bytes.Equal(pm.Receipts.dbType(), kv.PruneTypeOlder) && bytes.Equal(pruneMode.Receipts.dbType(), kv.PruneTypeBefore) {
+				log.Error("--prune=r flag has been changed to mean pruning of receipts before the Beacon Chain genesis. Please re-sync Erigon from scratch. " +
+					"Alternatively, enforce the old behaviour explicitly by --prune.r.older=90000 flag at the risk of breaking the Consensus Layer.")
+			}
 			return pm, errors.New("not allowed change of --prune flag, last time you used: " + pm.String())
 		}
 	}

turbo/cli/flags.go

@@ -64,26 +64,28 @@ var (
 	r - prune receipts (Receipts, Logs, LogTopicIndex, LogAddressIndex - used by eth_getLogs and similar RPC methods)
 	t - prune transaction by it's hash index
 	c - prune call traces (used by trace_filter method)
-	Does delete data older than 90K blocks, --prune=h is shortcut for: --prune.h.older=90_000 
-	If item is NOT in the list - means NO pruning for this data.
-	Example: --prune=hrtc`,
+	Does delete data older than 90K blocks, --prune=h is shortcut for: --prune.h.older=90000.
+	Similarly, --prune=t is shortcut for: --prune.t.older=90000 and --prune=c is shortcut for: --prune.c.older=90000.
+	However, --prune=r means to prune receipts before the Beacon Chain genesis (Consensus Layer might need receipts after that).
+	If an item is NOT on the list - means NO pruning for this data.
+	Example: --prune=htc`,
 		Value: "disabled",
 	}
 	PruneHistoryFlag = cli.Uint64Flag{
 		Name:  "prune.h.older",
-		Usage: `Prune data after this amount of blocks (if --prune flag has 'h', then default is 90K)`,
+		Usage: `Prune data older than this number of blocks from the tip of the chain (if --prune flag has 'h', then default is 90K)`,
 	}
 	PruneReceiptFlag = cli.Uint64Flag{
 		Name:  "prune.r.older",
-		Usage: `Prune data after this amount of blocks (if --prune flag has 'r', then default is 90K)`,
+		Usage: `Prune data older than this number of blocks from the tip of the chain`,
 	}
 	PruneTxIndexFlag = cli.Uint64Flag{
 		Name:  "prune.t.older",
-		Usage: `Prune data after this amount of blocks (if --prune flag has 't', then default is 90K)`,
+		Usage: `Prune data older than this number of blocks from the tip of the chain (if --prune flag has 't', then default is 90K)`,
 	}
 	PruneCallTracesFlag = cli.Uint64Flag{
 		Name:  "prune.c.older",
-		Usage: `Prune data after this amount of blocks (if --prune flag has 'c', then default is 90K)`,
+		Usage: `Prune data older than this number of blocks from the tip of the chain (if --prune flag has 'c', then default is 90K)`,
 	}
 
 	PruneHistoryBeforeFlag = cli.Uint64Flag{