scripts: add compare-states, related to #2337

Allows to quickly find the bad block and compare application
logs. Theoretically could also walk through the MPT to find the difference
there, but it's not needed now.

go.mod

@@ -4,6 +4,7 @@ require (
 	github.com/abiosoft/ishell/v2 v2.0.2
 	github.com/abiosoft/readline v0.0.0-20180607040430-155bce2042db
 	github.com/btcsuite/btcd v0.22.0-beta
+	github.com/davecgh/go-spew v1.1.1
 	github.com/gorilla/websocket v1.4.2
 	github.com/hashicorp/golang-lru v0.5.4
 	github.com/holiman/uint256 v1.2.0
@@ -13,6 +14,7 @@ require (
 	github.com/nspcc-dev/neofs-sdk-go v0.0.0-20220113123743-7f3162110659
 	github.com/nspcc-dev/rfc6979 v0.2.0
 	github.com/pierrec/lz4 v2.6.1+incompatible
+	github.com/pmezard/go-difflib v1.0.0
 	github.com/prometheus/client_golang v1.11.0
 	github.com/stretchr/testify v1.7.0
 	github.com/syndtr/goleveldb v1.0.1-0.20210305035536-64b5b1c73954

scripts/compare-states/compare-states.go

@@ -0,0 +1,146 @@
+package main
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"os"
+
+	"github.com/davecgh/go-spew/spew"
+	"github.com/nspcc-dev/neo-go/pkg/rpc/client"
+	"github.com/nspcc-dev/neo-go/pkg/util"
+	"github.com/pmezard/go-difflib/difflib"
+	"github.com/urfave/cli"
+)
+
+func initClient(addr string, name string) (*client.Client, uint32, error) {
+	c, err := client.New(context.Background(), addr, client.Options{})
+	if err != nil {
+		return nil, 0, fmt.Errorf("RPC %s: %w", name, err)
+	}
+	err = c.Init()
+	if err != nil {
+		return nil, 0, fmt.Errorf("RPC %s init: %w", name, err)
+	}
+	h, err := c.GetBlockCount()
+	if err != nil {
+		return nil, 0, fmt.Errorf("RPC %s block count: %w", name, err)
+	}
+	return c, h, nil
+}
+
+func getRoots(ca *client.Client, cb *client.Client, h uint32) (util.Uint256, util.Uint256, error) {
+	ra, err := ca.GetStateRootByHeight(h)
+	if err != nil {
+		return util.Uint256{}, util.Uint256{}, fmt.Errorf("getstateroot from A for %d: %w", h, err)
+	}
+	rb, err := cb.GetStateRootByHeight(h)
+	if err != nil {
+		return util.Uint256{}, util.Uint256{}, fmt.Errorf("getstateroot from B for %d: %w", h, err)
+	}
+	return ra.Root, rb.Root, nil
+}
+
+func bisectState(ca *client.Client, cb *client.Client, h uint32) (uint32, error) {
+	ra, rb, err := getRoots(ca, cb, 0)
+	if err != nil {
+		return 0, err
+	}
+	fmt.Printf("at %d: %s vs %s\n", 0, ra.StringLE(), rb.StringLE())
+	if ra != rb {
+		return 0, nil
+	}
+	good := uint32(0)
+	ra, rb, err = getRoots(ca, cb, h)
+	if err != nil {
+		return 0, err
+	}
+	fmt.Printf("at %d: %s vs %s\n", h, ra.StringLE(), rb.StringLE())
+	if ra.Equals(rb) {
+		return 0, fmt.Errorf("state matches at %d", h)
+	}
+	bad := h
+	for bad-good > 1 {
+		next := good + (bad-good)/2
+		ra, rb, err = getRoots(ca, cb, next)
+		if err != nil {
+			return 0, err
+		}
+		fmt.Printf("at %d: %s vs %s\n", next, ra.StringLE(), rb.StringLE())
+		if ra == rb {
+			good = next
+		} else {
+			bad = next
+		}
+	}
+	return bad, nil
+}
+
+func cliMain(c *cli.Context) error {
+	a := c.Args().Get(0)
+	b := c.Args().Get(1)
+	if a == "" {
+		return errors.New("no arguments given")
+	}
+	if b == "" {
+		return errors.New("missing second argument")
+	}
+	ca, ha, err := initClient(a, "A")
+	if err != nil {
+		return err
+	}
+	cb, hb, err := initClient(b, "B")
+	if err != nil {
+		return err
+	}
+	if ha != hb {
+		return errors.New("chains have different heights")
+	}
+	h, err := bisectState(ca, cb, ha-1)
+	if err != nil {
+		return err
+	}
+	blk, err := ca.GetBlockByIndex(h)
+	if err != nil {
+		return err
+	}
+	fmt.Printf("state differs at %d, block %s\n", h, blk.Hash().StringLE())
+	for _, t := range blk.Transactions {
+		fmt.Printf("transaction %s:\n", t.Hash().StringLE())
+		la, err := ca.GetApplicationLog(t.Hash(), nil)
+		if err != nil {
+			return err
+		}
+		lb, err := cb.GetApplicationLog(t.Hash(), nil)
+		if err != nil {
+			return err
+		}
+		da := spew.Sdump(la)
+		db := spew.Sdump(lb)
+		diff, _ := difflib.GetUnifiedDiffString(difflib.UnifiedDiff{
+			A:        difflib.SplitLines(da),
+			B:        difflib.SplitLines(db),
+			FromFile: a,
+			FromDate: "",
+			ToFile:   b,
+			ToDate:   "",
+			Context:  1,
+		})
+		fmt.Println(diff)
+	}
+	return nil
+}
+
+func main() {
+	ctl := cli.NewApp()
+	ctl.Name = "compare-states"
+	ctl.Version = "1.0"
+	ctl.Usage = "compare-states RPC_A RPC_B"
+	ctl.Action = cliMain
+
+	if err := ctl.Run(os.Args); err != nil {
+		fmt.Fprintln(os.Stderr, err)
+		fmt.Fprintln(os.Stderr, ctl.Usage)
+		os.Exit(1)
+	}
+}