Merge pull request #2551 from filecoin-project/feat/helptext-helpers

add a helper to make printing helptext on errors easier

cli/helper.go

@@ -0,0 +1,46 @@
+package cli
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/urfave/cli/v2"
+	"golang.org/x/xerrors"
+)
+
+type PrintHelpErr struct {
+	Err error
+	Ctx *cli.Context
+}
+
+func (e *PrintHelpErr) Error() string {
+	return e.Err.Error()
+}
+
+func (e *PrintHelpErr) Unwrap() error {
+	return e.Err
+}
+
+func (e *PrintHelpErr) Is(o error) bool {
+	_, ok := o.(*PrintHelpErr)
+	return ok
+}
+
+func ShowHelp(cctx *cli.Context, err error) error {
+	return &PrintHelpErr{Err: err, Ctx: cctx}
+}
+
+func RunApp(app *cli.App) {
+	if err := app.Run(os.Args); err != nil {
+		if os.Getenv("LOTUS_DEV") != "" {
+			log.Warnf("%+v", err)
+		} else {
+			fmt.Printf("ERROR: %s\n\n", err)
+		}
+		var phe *PrintHelpErr
+		if xerrors.As(err, &phe) {
+			cli.ShowCommandHelp(phe.Ctx, phe.Ctx.Command.Name)
+		}
+		os.Exit(1)
+	}
+}

cmd/lotus-storage-miner/main.go

@@ -3,7 +3,6 @@ package main
 import (
 	"context"
 	"fmt"
-	"os"
 
 	logging "github.com/ipfs/go-log/v2"
 	"github.com/urfave/cli/v2"
@@ -96,10 +95,7 @@ func main() {
 	app.Setup()
 	app.Metadata["repoType"] = repo.StorageMiner
 
-	if err := app.Run(os.Args); err != nil {
-		log.Warnf("%+v", err)
-		os.Exit(1)
-	}
+	lcli.RunApp(app)
 }
 
 func getActorAddress(ctx context.Context, nodeAPI api.StorageMiner, overrideMaddr string) (maddr address.Address, err error) {

cmd/lotus-storage-miner/sectors.go

@@ -251,15 +251,16 @@ var sectorsMarkForUpgradeCmd = &cli.Command{
 	Usage:     "Mark a committed capacity sector for replacement by a sector with deals",
 	ArgsUsage: "<sectorNum>",
 	Action: func(cctx *cli.Context) error {
+		if cctx.Args().Len() != 1 {
+			return lcli.ShowHelp(cctx, xerrors.Errorf("must pass sector number"))
+		}
+
 		nodeApi, closer, err := lcli.GetStorageMinerAPI(cctx)
 		if err != nil {
 			return err
 		}
 		defer closer()
 		ctx := lcli.ReqContext(cctx)
-		if cctx.Args().Len() != 1 {
-			return xerrors.Errorf("must pass sector number")
-		}
 
 		id, err := strconv.ParseUint(cctx.Args().Get(0), 10, 64)
 		if err != nil {