run golangci-lint and apply suggested fixes

zfs/datasetpath_visitor.go

@@ -108,8 +108,7 @@ func (t *datasetPathTree) WalkTopDown(parent []string, visitor DatasetPathsVisit
 
 func newDatasetPathTree(initialComps []string) (t *datasetPathTree) {
 	t = &datasetPathTree{}
-	var cur *datasetPathTree
-	cur = t
+	cur := t
 	for i, comp := range initialComps {
 		cur.Component = comp
 		cur.FilledIn = true

zfs/replication_history.go

@@ -31,6 +31,9 @@ func ZFSSetReplicationCursor(fs *DatasetPath, snapname string) (guid uint64, err
 		return 0, errors.Wrap(err, "zfs: replication cursor: get snapshot createtxg")
 	}
 	snapGuid, err := strconv.ParseUint(propsSnap.Get("guid"), 10, 64)
+	if err != nil {
+		return 0, errors.Wrap(err, "zfs: replication cursor: parse snapshot guid")
+	}
 	bookmarkPath := fmt.Sprintf("%s#%s", fs.ToString(), ReplicationCursorBookmarkName)
 	propsBookmark, err := zfsGet(bookmarkPath, []string{"createtxg"}, sourceAny)
 	_, bookmarkNotExistErr := err.(*DatasetDoesNotExist)

zfs/versions.go

@@ -3,13 +3,13 @@ package zfs
 import (
 	"bytes"
 	"context"
-	"errors"
 	"fmt"
 	"io"
 	"strconv"
 	"strings"
 	"time"
 
+	"github.com/pkg/errors"
 	"github.com/prometheus/client_golang/prometheus"
 )
 
@@ -17,7 +17,7 @@ type VersionType string
 
 const (
 	Bookmark VersionType = "bookmark"
-	Snapshot             = "snapshot"
+	Snapshot VersionType = "snapshot"
 )
 
 func (t VersionType) DelimiterChar() string {
@@ -37,14 +37,14 @@ func (t VersionType) String() string {
 
 func DecomposeVersionString(v string) (fs string, versionType VersionType, name string, err error) {
 	if len(v) < 3 {
-		err = errors.New(fmt.Sprintf("snapshot or bookmark name implausibly short: %s", v))
+		err = fmt.Errorf("snapshot or bookmark name implausibly short: %s", v)
 		return
 	}
 
 	snapSplit := strings.SplitN(v, "@", 2)
 	bookmarkSplit := strings.SplitN(v, "#", 2)
 	if len(snapSplit)*len(bookmarkSplit) != 2 {
-		err = errors.New(fmt.Sprintf("dataset cannot be snapshot and bookmark at the same time: %s", v))
+		err = fmt.Errorf("dataset cannot be snapshot and bookmark at the same time: %s", v)
 		return
 	}
 
@@ -122,12 +122,12 @@ func ZFSListFilesystemVersions(fs *DatasetPath, filter FilesystemVersionFilter)
 		}
 
 		if v.Guid, err = strconv.ParseUint(line[1], 10, 64); err != nil {
-			err = errors.New(fmt.Sprintf("cannot parse GUID: %s", err.Error()))
+			err = errors.Wrap(err, "cannot parse GUID")
 			return
 		}
 
 		if v.CreateTXG, err = strconv.ParseUint(line[2], 10, 64); err != nil {
-			err = errors.New(fmt.Sprintf("cannot parse CreateTXG: %s", err.Error()))
+			err = errors.Wrap(err, "cannot parse CreateTXG")
 			return
 		}
 
@@ -160,16 +160,9 @@ func ZFSDestroyFilesystemVersion(filesystem *DatasetPath, version *FilesystemVer
 	datasetPath := version.ToAbsPath(filesystem)
 
 	// Sanity check...
-	if strings.IndexAny(datasetPath, "@#") == -1 {
-		return fmt.Errorf("sanity check failed: no @ character found in dataset path: %s", datasetPath)
+	if !strings.ContainsAny(datasetPath, "@#") {
+		return fmt.Errorf("sanity check failed: no @ or # character found in %q", datasetPath)
 	}
 
-	err = ZFSDestroy(datasetPath)
-	if err == nil {
-		return
-	}
-
-	// Check for EBUSY, special meaning to us
-	return
-
+	return ZFSDestroy(datasetPath)
 }

zfs/zfs.go

@@ -67,7 +67,6 @@ func (p *DatasetPath) TrimPrefix(prefix *DatasetPath) {
 	for i := 0; i < newlen; i++ {
 		p.comps[i] = oldcomps[prelen+i]
 	}
-	return
 }
 
 func (p *DatasetPath) TrimNPrefixComps(n int) {
@@ -251,7 +250,9 @@ func ZFSListChan(ctx context.Context, out chan ZFSListResult, properties []strin
 		return
 	}
 	defer func() {
-		cmd.Wait()
+		// discard the error, this defer is only relevant if we return while parsing the output
+		// in which case we'll return an 'unexpected output' error and not the exit status
+		_ = cmd.Wait()
 	}()
 
 	s := bufio.NewScanner(stdout)
@@ -283,7 +284,6 @@ func ZFSListChan(ctx context.Context, out chan ZFSListResult, properties []strin
 		sendResult(nil, s.Err())
 		return
 	}
-	return
 }
 
 func validateRelativeZFSVersion(s string) error {
@@ -731,7 +731,7 @@ func ZFSRecv(ctx context.Context, fs string, streamCopier StreamCopier, opts Rec
 		{
 			vs, err := ZFSListFilesystemVersions(fsdp, nil)
 			if err != nil {
-				err = fmt.Errorf("cannot list versions to rollback is required: %s", err)
+				return fmt.Errorf("cannot list versions for rollback for forced receive: %s", err)
 			}
 			for _, v := range vs {
 				if v.Type == Snapshot {

zfs/zfs_debug.go

@@ -13,6 +13,7 @@ func init() {
 	}
 }
 
+//nolint[:deadcode,unused]
 func debug(format string, args ...interface{}) {
 	if debugEnabled {
 		fmt.Fprintf(os.Stderr, "zfs: %s\n", fmt.Sprintf(format, args...))