fix: return error when to and from are invalid

Author: frrist

commands/export.go

@@ -6,13 +6,14 @@ import (
 	"os"
 
 	"github.com/filecoin-project/go-state-types/abi"
-	"github.com/filecoin-project/lily/chain/export"
 	"github.com/filecoin-project/lotus/blockstore"
 	"github.com/filecoin-project/lotus/chain/store"
 	"github.com/filecoin-project/lotus/node/repo"
 	"github.com/mitchellh/go-homedir"
 	"github.com/urfave/cli/v2"
 	"golang.org/x/xerrors"
+
+	"github.com/filecoin-project/lily/chain/export"
 )
 
 type chainExportOps struct {
@@ -109,7 +110,7 @@ Some examples:
 	Before: func(cctx *cli.Context) error {
 		from, to := chainExportFlags.from, chainExportFlags.to
 		if to < from {
-			xerrors.Errorf("value of --to (%d) should be >= --from (%d)", to, from)
+			return xerrors.Errorf("value of --to (%d) should be >= --from (%d)", to, from)
 		}
 
 		return nil

commands/gap.go

@@ -6,11 +6,12 @@ import (
 	"strings"
 	"time"
 
-	"github.com/filecoin-project/lily/chain"
-	"github.com/filecoin-project/lily/lens/lily"
 	lotuscli "github.com/filecoin-project/lotus/cli"
 	"github.com/urfave/cli/v2"
 	"golang.org/x/xerrors"
+
+	"github.com/filecoin-project/lily/chain"
+	"github.com/filecoin-project/lily/lens/lily"
 )
 
 type gapOps struct {
@@ -91,7 +92,7 @@ var GapFillCmd = &cli.Command{
 	Before: func(cctx *cli.Context) error {
 		from, to := gapFlags.from, gapFlags.to
 		if to < from {
-			xerrors.Errorf("value of --to (%d) should be >= --from (%d)", to, from)
+			return xerrors.Errorf("value of --to (%d) should be >= --from (%d)", to, from)
 		}
 
 		return nil

commands/walk.go

@@ -6,12 +6,13 @@ import (
 	"strings"
 	"time"
 
-	"github.com/filecoin-project/lily/chain/actors/builtin"
-	"github.com/filecoin-project/lily/lens/lily"
 	lotuscli "github.com/filecoin-project/lotus/cli"
 	"github.com/urfave/cli/v2"
 	"golang.org/x/xerrors"
 
+	"github.com/filecoin-project/lily/chain/actors/builtin"
+	"github.com/filecoin-project/lily/lens/lily"
+
 	"github.com/filecoin-project/lily/chain"
 )
 
@@ -92,7 +93,7 @@ var WalkCmd = &cli.Command{
 	Before: func(cctx *cli.Context) error {
 		from, to := walkFlags.from, walkFlags.to
 		if to < from {
-			xerrors.Errorf("value of --to (%d) should be >= --from (%d)", to, from)
+			return xerrors.Errorf("value of --to (%d) should be >= --from (%d)", to, from)
 		}
 
 		return nil