switched fmt.Errorf() to errors.Wrap()

cli/app.go

@@ -3,7 +3,6 @@
 
 import (
 	"context"
-	"fmt"
 	"net/http"
 	"os"
 	"time"
@@ -13,6 +12,7 @@
 	"github.com/kopia/repo"
 	"github.com/kopia/repo/block"
 	"github.com/kopia/repo/storage"
+	"github.com/pkg/errors"
 
 	kingpin "gopkg.in/alecthomas/kingpin.v2"
 )
@@ -76,7 +76,7 @@ func repositoryAction(act func(ctx context.Context, rep *repo.Repository) error)
 
 		reportSubcommandFinished(kpc.SelectedCommand.FullCommand(), err == nil, storageType, rep.Blocks.Format.Version, commandDuration)
 		if cerr := rep.Close(ctx); cerr != nil {
-			return fmt.Errorf("unable to close repository: %v", cerr)
+			return errors.Wrap(cerr, "unable to close repository")
 		}
 		return err
 	}

cli/command_block_gc.go

@@ -2,9 +2,9 @@
 
 import (
 	"context"
-	"fmt"
 
 	"github.com/kopia/repo"
+	"github.com/pkg/errors"
 )
 
 var (
@@ -15,7 +15,7 @@
 func runBlockGarbageCollectAction(ctx context.Context, rep *repo.Repository) error {
 	unused, err := rep.Blocks.FindUnreferencedStorageFiles(ctx)
 	if err != nil {
-		return fmt.Errorf("error looking for unreferenced storage files: %v", err)
+		return errors.Wrap(err, "error looking for unreferenced storage files")
 	}
 
 	if len(unused) == 0 {
@@ -37,7 +37,7 @@ func runBlockGarbageCollectAction(ctx context.Context, rep *repo.Repository) err
 	for _, u := range unused {
 		printStderr("Deleting unused block %q (%v bytes)...\n", u.BlockID, u.Length)
 		if err := rep.Storage.DeleteBlock(ctx, u.BlockID); err != nil {
-			return fmt.Errorf("unable to delete block %q: %v", u.BlockID, err)
+			return errors.Wrapf(err, "unable to delete block %q", u.BlockID)
 		}
 	}
 

cli/command_block_rewrite.go

@@ -8,6 +8,7 @@
 
 	"github.com/kopia/repo"
 	"github.com/kopia/repo/block"
+	"github.com/pkg/errors"
 )
 
 var (
@@ -121,7 +122,7 @@ func findBlockInfos(ctx context.Context, rep *repo.Repository, ch chan blockInfo
 func findBlocksWithFormatVersion(ctx context.Context, rep *repo.Repository, ch chan blockInfoOrError, version int) {
 	infos, err := rep.Blocks.ListBlockInfos("", true)
 	if err != nil {
-		ch <- blockInfoOrError{err: fmt.Errorf("unable to list index blocks: %v", err)}
+		ch <- blockInfoOrError{err: errors.Wrap(err, "unable to list index blocks")}
 		return
 	}
 
@@ -136,14 +137,14 @@ func findBlocksInShortPacks(ctx context.Context, rep *repo.Repository, ch chan b
 	log.Debugf("listing blocks...")
 	infos, err := rep.Blocks.ListBlockInfos("", true)
 	if err != nil {
-		ch <- blockInfoOrError{err: fmt.Errorf("unable to list index blocks: %v", err)}
+		ch <- blockInfoOrError{err: errors.Wrap(err, "unable to list index blocks")}
 		return
 	}
 
 	log.Debugf("finding blocks in short packs...")
 	shortPackBlocks, err := findShortPackBlocks(infos, threshold)
 	if err != nil {
-		ch <- blockInfoOrError{err: fmt.Errorf("unable to find short pack blocks: %v", err)}
+		ch <- blockInfoOrError{err: errors.Wrap(err, "unable to find short pack blocks")}
 		return
 	}
 	log.Debugf("found %v short pack blocks", len(shortPackBlocks))

cli/command_block_verify.go

@@ -5,6 +5,7 @@
 	"fmt"
 
 	"github.com/kopia/repo"
+	"github.com/pkg/errors"
 )
 
 var (
@@ -29,7 +30,7 @@ func runVerifyBlockCommand(ctx context.Context, rep *repo.Repository) error {
 func verifyAllBlocks(ctx context.Context, rep *repo.Repository) error {
 	blockIDs, err := rep.Blocks.ListBlocks("")
 	if err != nil {
-		return fmt.Errorf("unable to list blocks: %v", err)
+		return errors.Wrap(err, "unable to list blocks")
 	}
 
 	var errorCount int

cli/command_cache_clear.go

@@ -2,10 +2,10 @@
 
 import (
 	"context"
-	"fmt"
 	"os"
 
 	"github.com/kopia/repo"
+	"github.com/pkg/errors"
 )
 
 var (
@@ -28,7 +28,7 @@ func runCacheClearCommand(ctx context.Context, rep *repo.Repository) error {
 		return nil
 	}
 
-	return fmt.Errorf("caching not enabled")
+	return errors.New("caching not enabled")
 }
 
 func init() {

cli/command_diff.go

@@ -2,13 +2,13 @@
 
 import (
 	"context"
-	"fmt"
 	"os"
 	"strings"
 
 	"github.com/kopia/kopia/internal/diff"
 	"github.com/kopia/kopia/snapshot/snapshotfs"
 	"github.com/kopia/repo"
+	"github.com/pkg/errors"
 )
 
 var (
@@ -32,7 +32,7 @@ func runDiffCommand(ctx context.Context, rep *repo.Repository) error {
 	isDir1 := strings.HasPrefix(string(oid1), "k")
 	isDir2 := strings.HasPrefix(string(oid2), "k")
 	if isDir1 != isDir2 {
-		return fmt.Errorf("arguments do diff must both be directories or both non-directories")
+		return errors.New("arguments do diff must both be directories or both non-directories")
 	}
 
 	d, err := diff.NewComparer(rep, os.Stdout)
@@ -55,7 +55,7 @@ func runDiffCommand(ctx context.Context, rep *repo.Repository) error {
 		)
 	}
 
-	return fmt.Errorf("comparing files not implemented yet")
+	return errors.New("comparing files not implemented yet")
 }
 
 func defaultDiffCommand() string {

cli/command_mount_browse.go

@@ -1,10 +1,10 @@
 package cli
 
 import (
-	"fmt"
 	"os"
 	"os/exec"
 
+	"github.com/pkg/errors"
 	"github.com/skratchdot/open-golang/open"
 )
 
@@ -50,7 +50,7 @@ func netUSE(mountPoint string, addr string) error {
 	c.Stderr = os.Stderr
 	c.Stdin = os.Stdin
 	if err := c.Run(); err != nil {
-		return fmt.Errorf("unable to mount: %v", err)
+		return errors.Wrap(err, "unable to mount")
 	}
 
 	startWebBrowser("x:\\")
@@ -61,7 +61,7 @@ func netUSE(mountPoint string, addr string) error {
 	c.Stderr = os.Stderr
 	c.Stdin = os.Stdin
 	if err := c.Run(); err != nil {
-		return fmt.Errorf("unable to unmount: %v", err)
+		return errors.Wrap(err, "unable to unmount")
 	}
 
 	return nil

cli/command_mount_nofuse.go

@@ -3,9 +3,8 @@
 package cli
 
 import (
-	"fmt"
-
 	"github.com/kopia/kopia/fs"
+	"github.com/pkg/errors"
 )
 
 var (
@@ -13,5 +12,5 @@
 )
 
 func mountDirectoryFUSE(entry fs.Directory, mountPoint string) error {
-	return fmt.Errorf("FUSE is not supported")
+	return errors.New("FUSE is not supported")
 }

cli/command_policy.go

@@ -2,16 +2,16 @@
 
 import (
 	"context"
-	"fmt"
 
 	"github.com/kopia/kopia/snapshot"
 	"github.com/kopia/kopia/snapshot/policy"
 	"github.com/kopia/repo"
+	"github.com/pkg/errors"
 )
 
 func policyTargets(ctx context.Context, rep *repo.Repository, globalFlag *bool, targetsFlag *[]string) ([]snapshot.SourceInfo, error) {
 	if *globalFlag == (len(*targetsFlag) > 0) {
-		return nil, fmt.Errorf("must pass either '--global' or a list of path targets")
+		return nil, errors.New("must pass either '--global' or a list of path targets")
 	}
 
 	if *globalFlag {

cli/command_policy_set.go

@@ -8,9 +8,10 @@
 	"strings"
 
 	"github.com/kopia/kopia/fs/ignorefs"
-	"github.com/kopia/repo"
 	"github.com/kopia/kopia/snapshot"
 	"github.com/kopia/kopia/snapshot/policy"
+	"github.com/kopia/repo"
+	"github.com/pkg/errors"
 )
 
 var (
@@ -73,7 +74,7 @@ func setPolicy(ctx context.Context, rep *repo.Repository) error {
 		}
 
 		if changeCount == 0 {
-			return fmt.Errorf("no changes specified")
+			return errors.New("no changes specified")
 		}
 
 		if err := policy.SetPolicy(ctx, rep, target, p); err != nil {
@@ -86,19 +87,19 @@ func setPolicy(ctx context.Context, rep *repo.Repository) error {
 
 func setPolicyFromFlags(target snapshot.SourceInfo, p *policy.Policy, changeCount *int) error {
 	if err := setRetentionPolicyFromFlags(&p.RetentionPolicy, changeCount); err != nil {
-		return fmt.Errorf("retention policy: %v", err)
+		return errors.Wrap(err, "retention policy")
 	}
 
 	if err := setFilesPolicyFromFlags(&p.FilesPolicy, changeCount); err != nil {
-		return fmt.Errorf("files policy: %v", err)
+		return errors.Wrap(err, "files policy")
 	}
 
 	if err := setSchedulingPolicyFromFlags(&p.SchedulingPolicy, changeCount); err != nil {
-		return fmt.Errorf("scheduling policy: %v", err)
+		return errors.Wrap(err, "scheduling policy")
 	}
 
 	if err := applyPolicyNumber64("maximum file size", &p.FilesPolicy.MaxFileSize, *policySetMaxFileSize, changeCount); err != nil {
-		return fmt.Errorf("maximum file size: %v", err)
+		return errors.Wrap(err, "maximum file size")
 	}
 
 	// It's not really a list, just optional boolean, last one wins.
@@ -171,7 +172,7 @@ func setSchedulingPolicyFromFlags(sp *policy.SchedulingPolicy, changeCount *int)
 
 				var timeOfDay policy.TimeOfDay
 				if err := timeOfDay.Parse(tod); err != nil {
-					return fmt.Errorf("unable to parse time of day: %v", err)
+					return errors.Wrap(err, "unable to parse time of day")
 				}
 				timesOfDay = append(timesOfDay, timeOfDay)
 			}

cli/command_repository_connect.go

@@ -2,12 +2,12 @@
 
 import (
 	"context"
-	"fmt"
 	"time"
 
 	"github.com/kopia/repo"
 	"github.com/kopia/repo/block"
 	"github.com/kopia/repo/storage"
+	"github.com/pkg/errors"
 
 	"gopkg.in/alecthomas/kingpin.v2"
 )
@@ -56,7 +56,7 @@ func runConnectCommandWithStorageAndPassword(ctx context.Context, st storage.Sto
 
 	if connectPersistCredentials {
 		if err := persistPassword(configFile, getUserName(), password); err != nil {
-			return fmt.Errorf("unable to persist password: %v", err)
+			return errors.Wrap(err, "unable to persist password")
 		}
 	} else {
 		deletePassword(configFile, getUserName())

cli/command_repository_connect_from_config.go

@@ -2,11 +2,11 @@
 
 import (
 	"context"
-	"fmt"
 	"os"
 
 	"github.com/kopia/repo"
 	"github.com/kopia/repo/storage"
+	"github.com/pkg/errors"
 	kingpin "gopkg.in/alecthomas/kingpin.v2"
 )
 
@@ -17,12 +17,12 @@ func connectToStorageFromConfig(ctx context.Context) (storage.Storage, error) {
 
 	f, err := os.Open(connectToStorageFromConfigPath)
 	if err != nil {
-		return nil, fmt.Errorf("unable to open config: %v", err)
+		return nil, errors.Wrap(err, "unable to open config")
 	}
 	defer f.Close() //nolint:errcheck
 
 	if err := cfg.Load(f); err != nil {
-		return nil, fmt.Errorf("unable to load config: %v", err)
+		return nil, errors.Wrap(err, "unable to load config")
 	}
 
 	return storage.NewStorage(ctx, cfg.Storage)

cli/command_repository_create.go

@@ -2,8 +2,6 @@
 
 import (
 	"context"
-	"errors"
-	"fmt"
 	"strings"
 
 	"github.com/kopia/kopia/fs/ignorefs"
@@ -13,6 +11,7 @@
 	"github.com/kopia/repo/block"
 	"github.com/kopia/repo/object"
 	"github.com/kopia/repo/storage"
+	"github.com/pkg/errors"
 )
 
 var (
@@ -69,7 +68,7 @@ func ensureEmpty(ctx context.Context, s storage.Storage) error {
 	})
 	if err == hasDataError {
 		if !*createOverwrite {
-			return fmt.Errorf("found existing data in storage, specify --overwrite to use anyway")
+			return errors.New("found existing data in storage, specify --overwrite to use anyway")
 		}
 	}
 
@@ -79,7 +78,7 @@ func ensureEmpty(ctx context.Context, s storage.Storage) error {
 func runCreateCommandWithStorage(ctx context.Context, st storage.Storage) error {
 	err := ensureEmpty(ctx, st)
 	if err != nil {
-		return fmt.Errorf("unable to get repository storage: %v", err)
+		return errors.Wrap(err, "unable to get repository storage")
 	}
 
 	options := newRepositoryOptionsFromFlags()
@@ -104,7 +103,7 @@ func runCreateCommandWithStorage(ctx context.Context, st storage.Storage) error
 	}
 
 	if err := repo.Initialize(ctx, st, options, password); err != nil {
-		return fmt.Errorf("cannot initialize repository: %v", err)
+		return errors.Wrap(err, "cannot initialize repository")
 	}
 
 	if *createOnly {
@@ -112,7 +111,7 @@ func runCreateCommandWithStorage(ctx context.Context, st storage.Storage) error
 	}
 
 	if err := runConnectCommandWithStorageAndPassword(ctx, st, password); err != nil {
-		return fmt.Errorf("unable to connect to repository: %v", err)
+		return errors.Wrap(err, "unable to connect to repository")
 	}
 
 	return populateRepository(ctx, password)
@@ -121,17 +120,17 @@ func runCreateCommandWithStorage(ctx context.Context, st storage.Storage) error
 func populateRepository(ctx context.Context, password string) error {
 	rep, err := repo.Open(ctx, repositoryConfigFileName(), password, applyOptionsFromFlags(nil))
 	if err != nil {
-		return fmt.Errorf("unable to open repository: %v", err)
+		return errors.Wrap(err, "unable to open repository")
 	}
 	defer rep.Close(ctx) //nolint:errcheck
 
 	globalPolicy, err := getInitialGlobalPolicy()
 	if err != nil {
-		return fmt.Errorf("unable to initialize global policy: %v", err)
+		return errors.Wrap(err, "unable to initialize global policy")
 	}
 
 	if err := policy.SetPolicy(ctx, rep, policy.GlobalPolicySourceInfo, globalPolicy); err != nil {
-		return fmt.Errorf("unable to set global policy: %v", err)
+		return errors.Wrap(err, "unable to set global policy")
 	}
 
 	printPolicy(globalPolicy, nil)
@@ -148,7 +147,7 @@ func getInitialGlobalPolicy() (*policy.Policy, error) {
 		for _, tod := range strings.Split(tods, ",") {
 			var timeOfDay policy.TimeOfDay
 			if err := timeOfDay.Parse(tod); err != nil {
-				return nil, fmt.Errorf("unable to parse time of day: %v", err)
+				return nil, errors.Wrap(err, "unable to parse time of day")
 			}
 			timesOfDay = append(timesOfDay, timeOfDay)
 		}

cli/command_repository_repair.go

@@ -2,11 +2,10 @@
 
 import (
 	"context"
-	"errors"
-	"fmt"
 
 	"github.com/kopia/repo"
 	"github.com/kopia/repo/storage"
+	"github.com/pkg/errors"
 )
 
 var (
@@ -63,7 +62,7 @@ func recoverFormatBlock(ctx context.Context, st storage.Storage, prefix string)
 	case errSuccess:
 		return nil
 	case nil:
-		return fmt.Errorf("could not find a replica of a format block")
+		return errors.New("could not find a replica of a format block")
 	default:
 		return err
 	}

cli/command_server_start.go

@@ -2,12 +2,12 @@
 
 import (
 	"context"
-	"fmt"
 	"net/http"
 	"time"
 
 	"github.com/kopia/kopia/internal/server"
 	"github.com/kopia/repo"
+	"github.com/pkg/errors"
 )
 
 var (
@@ -24,7 +24,7 @@ func init() {
 func runServer(ctx context.Context, rep *repo.Repository) error {
 	srv, err := server.New(ctx, rep, getHostName(), getUserName())
 	if err != nil {
-		return fmt.Errorf("unable to initialize server: %v", err)
+		return errors.Wrap(err, "unable to initialize server")
 	}
 
 	go rep.RefreshPeriodically(ctx, 10*time.Second)

cli/command_snapshot_create.go

@@ -2,7 +2,6 @@
 
 import (
 	"context"
-	"errors"
 	"fmt"
 	"os"
 	"os/user"
@@ -15,6 +14,7 @@
 	"github.com/kopia/kopia/snapshot/policy"
 	"github.com/kopia/kopia/snapshot/snapshotfs"
 	"github.com/kopia/repo"
+	"github.com/pkg/errors"
 )
 
 const (
@@ -57,7 +57,7 @@ func runBackupCommand(ctx context.Context, rep *repo.Repository) error {
 	u.Progress = cliProgress
 
 	if len(*snapshotCreateDescription) > maxSnapshotDescriptionLength {
-		return fmt.Errorf("description too long")
+		return errors.New("description too long")
 	}
 
 	var finalErrors []string
@@ -80,7 +80,7 @@ func runBackupCommand(ctx context.Context, rep *repo.Repository) error {
 		return nil
 	}
 
-	return fmt.Errorf("encountered %v errors:\n%v", len(finalErrors), strings.Join(finalErrors, "\n"))
+	return errors.Errorf("encountered %v errors:\n%v", len(finalErrors), strings.Join(finalErrors, "\n"))
 }
 
 func snapshotSingleSource(ctx context.Context, rep *repo.Repository, u *snapshotfs.Uploader, sourceInfo snapshot.SourceInfo) error {
@@ -109,7 +109,7 @@ func snapshotSingleSource(ctx context.Context, rep *repo.Repository, u *snapshot
 
 	snapID, err := snapshot.SaveSnapshot(ctx, rep, manifest)
 	if err != nil {
-		return fmt.Errorf("cannot save manifest: %v", err)
+		return errors.Wrap(err, "cannot save manifest")
 	}
 
 	printStderr("uploaded snapshot %v (root %v) in %v\n", snapID, manifest.RootObjectID(), time.Since(t0))
@@ -122,7 +122,7 @@ func snapshotSingleSource(ctx context.Context, rep *repo.Repository, u *snapshot
 func findPreviousSnapshotManifest(ctx context.Context, rep *repo.Repository, sourceInfo snapshot.SourceInfo, noLaterThan *time.Time) (*snapshot.Manifest, error) {
 	previous, err := snapshot.ListSnapshots(ctx, rep, sourceInfo)
 	if err != nil {
-		return nil, fmt.Errorf("error listing previous backups: %v", err)
+		return nil, errors.Wrap(err, "error listing previous backups")
 	}
 
 	var previousManifest *snapshot.Manifest
@@ -151,7 +151,7 @@ func getLocalBackupPaths(ctx context.Context, rep *repo.Repository) ([]string, e
 
 	sources, err := snapshot.ListSources(ctx, rep)
 	if err != nil {
-		return nil, fmt.Errorf("unable to list sources: %v", err)
+		return nil, errors.Wrap(err, "unable to list sources")
 	}
 
 	var result []string

cli/command_snapshot_migrate.go

@@ -10,6 +10,7 @@
 	"github.com/kopia/kopia/snapshot"
 	"github.com/kopia/kopia/snapshot/snapshotfs"
 	"github.com/kopia/repo"
+	"github.com/pkg/errors"
 )
 
 var (
@@ -25,12 +26,12 @@
 func runMigrateCommand(ctx context.Context, destRepo *repo.Repository) error {
 	sourceRepo, err := repo.Open(ctx, *migrateSourceConfig, mustGetPasswordFromFlags(false, false), applyOptionsFromFlags(nil))
 	if err != nil {
-		return fmt.Errorf("can't open source repository: %v", err)
+		return errors.Wrap(err, "can't open source repository")
 	}
 
 	sources, err := getSourcesToMigrate(ctx, sourceRepo)
 	if err != nil {
-		return fmt.Errorf("can't retrieve sources: %v", err)
+		return errors.Wrap(err, "can't retrieve sources")
 	}
 
 	semaphore := make(chan struct{}, *migrateParallelism)
@@ -94,7 +95,7 @@ func runMigrateCommand(ctx context.Context, destRepo *repo.Repository) error {
 func findPreviousSnapshotManifestWithStartTime(ctx context.Context, rep *repo.Repository, sourceInfo snapshot.SourceInfo, startTime time.Time) (*snapshot.Manifest, error) {
 	previous, err := snapshot.ListSnapshots(ctx, rep, sourceInfo)
 	if err != nil {
-		return nil, fmt.Errorf("error listing previous backups: %v", err)
+		return nil, errors.Wrap(err, "error listing previous backups")
 	}
 
 	for _, p := range previous {
@@ -166,7 +167,7 @@ func migrateSingleSourceSnapshot(ctx context.Context, uploader *snapshotfs.Uploa
 	newm.Description = m.Description
 	if newm.IncompleteReason == "" {
 		if _, err := snapshot.SaveSnapshot(ctx, destRepo, newm); err != nil {
-			return fmt.Errorf("cannot save manifest: %v", err)
+			return errors.Wrap(err, "cannot save manifest")
 		}
 	}
 	return nil
@@ -199,7 +200,7 @@ func getSourcesToMigrate(ctx context.Context, rep *repo.Repository) ([]snapshot.
 		return snapshot.ListSources(ctx, rep)
 	}
 
-	return nil, fmt.Errorf("must specify either --all or --sources")
+	return nil, errors.New("must specify either --all or --sources")
 }
 
 func init() {

cli/config.go

@@ -13,6 +13,7 @@
 	"github.com/kopia/kopia/fs/loggingfs"
 	"github.com/kopia/kopia/internal/ospath"
 	"github.com/kopia/repo"
+	"github.com/pkg/errors"
 )
 
 var (
@@ -66,7 +67,7 @@ func waitForCtrlC() {
 func openRepository(ctx context.Context, opts *repo.Options) (*repo.Repository, error) {
 	r, err := repo.Open(ctx, repositoryConfigFileName(), mustGetPasswordFromFlags(false, true), applyOptionsFromFlags(opts))
 	if os.IsNotExist(err) {
-		return nil, fmt.Errorf("not connected to a repository, use 'kopia connect'")
+		return nil, errors.New("not connected to a repository, use 'kopia connect'")
 	}
 
 	return r, err

cli/password.go

@@ -11,6 +11,7 @@
 	"strings"
 
 	"github.com/bgentry/speakeasy"
+	"github.com/pkg/errors"
 	keyring "github.com/zalando/go-keyring"
 )
 
@@ -72,7 +73,7 @@ func askPass(prompt string) (string, error) {
 		return p, nil
 	}
 
-	return "", fmt.Errorf("can't get password")
+	return "", errors.New("can't get password")
 }
 
 func getPersistedPassword(configFile string, username string) (string, bool) {

cli/show_utils.go

@@ -11,6 +11,7 @@
 	"time"
 
 	"github.com/kopia/kopia/internal/units"
+	"github.com/pkg/errors"
 	"gopkg.in/alecthomas/kingpin.v2"
 )
 
@@ -34,7 +35,7 @@ func showContentWithFlags(rd io.Reader, unzip, indentJSON bool) error {
 	if unzip {
 		gz, err := gzip.NewReader(rd)
 		if err != nil {
-			return fmt.Errorf("unable to open gzip stream: %v", err)
+			return errors.Wrap(err, "unable to open gzip stream")
 		}
 
 		rd = gz

cli/storage_providers.go

@@ -2,9 +2,9 @@
 
 import (
 	"context"
-	"fmt"
 
 	"github.com/kopia/repo/storage"
+	"github.com/pkg/errors"
 	kingpin "gopkg.in/alecthomas/kingpin.v2"
 )
 
@@ -24,7 +24,7 @@ func RegisterStorageConnectFlags(
 			ctx := context.Background()
 			st, err := connect(ctx)
 			if err != nil {
-				return fmt.Errorf("can't connect to storage: %v", err)
+				return errors.Wrap(err, "can't connect to storage")
 			}
 
 			return runCreateCommandWithStorage(ctx, st)
@@ -38,7 +38,7 @@ func RegisterStorageConnectFlags(
 		ctx := context.Background()
 		st, err := connect(ctx)
 		if err != nil {
-			return fmt.Errorf("can't connect to storage: %v", err)
+			return errors.Wrap(err, "can't connect to storage")
 		}
 
 		return runConnectCommandWithStorage(ctx, st)
@@ -51,7 +51,7 @@ func RegisterStorageConnectFlags(
 		ctx := context.Background()
 		st, err := connect(ctx)
 		if err != nil {
-			return fmt.Errorf("can't connect to storage: %v", err)
+			return errors.Wrap(err, "can't connect to storage")
 		}
 
 		return runRepairCommandWithStorage(ctx, st)

fs/ignorefs/ignorefs.go

@@ -9,6 +9,7 @@
 
 	"github.com/kopia/kopia/fs"
 	"github.com/kopia/kopia/internal/ignore"
+	"github.com/pkg/errors"
 )
 
 // IgnoreCallback is a function called by ignorefs to report whenever a file or directory is being ignored while listing its parent.
@@ -208,7 +209,7 @@ func combineAndDedupe(slices ...[]string) []string {
 func parseIgnoreFile(ctx context.Context, baseDir string, file fs.File) ([]ignore.Matcher, error) {
 	f, err := file.Open(ctx)
 	if err != nil {
-		return nil, fmt.Errorf("unable to open ignore file: %v", err)
+		return nil, errors.Wrap(err, "unable to open ignore file")
 	}
 	defer f.Close() //nolint:errcheck
 

go.mod

@@ -14,6 +14,7 @@ require (
 	github.com/kopia/repo v0.3.0-pre2
 	github.com/kylelemons/godebug v0.0.0-20170820004349-d65d576e9348
 	github.com/op/go-logging v0.0.0-20160315200505-970db520ece7
+	github.com/pkg/errors v0.8.1
 	github.com/skratchdot/open-golang v0.0.0-20160302144031-75fb7ed4208c
 	github.com/stretchr/testify v1.3.0 // indirect
 	github.com/zalando/go-keyring v0.0.0-20190208082241-fbe81aec3a07

go.sum

@@ -51,6 +51,8 @@ github.com/mitchellh/go-homedir v1.0.0/go.mod h1:SfyaCUpYCn1Vlf4IUYiD9fPX4A5wJrk
 github.com/op/go-logging v0.0.0-20160315200505-970db520ece7 h1:lDH9UUVJtmYCjyT0CI4q8xvlXPxeZ0gYCVvWbmPlp88=
 github.com/op/go-logging v0.0.0-20160315200505-970db520ece7/go.mod h1:HzydrMdWErDVzsI23lYNej1Htcns9BCg93Dk0bBINWk=
 github.com/openzipkin/zipkin-go v0.1.1/go.mod h1:NtoC/o8u3JlF1lSlyPNswIbeQH9bJTmOf0Erfk+hxe8=
+github.com/pkg/errors v0.8.1 h1:iURUrRGxPUNPdy5/HRSm+Yj6okJ6UtLINN0Q9M4+h3I=
+github.com/pkg/errors v0.8.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/prometheus/client_golang v0.8.0/go.mod h1:7SWBe2y4D6OKWSNQJUaRYU/AaXPKyh/dDVn+NZz0KFw=

internal/diff/diff.go

@@ -13,6 +13,7 @@
 	"github.com/kopia/kopia/internal/kopialogging"
 	"github.com/kopia/repo"
 	"github.com/kopia/repo/object"
+	"github.com/pkg/errors"
 )
 
 var log = kopialogging.Logger("diff")
@@ -171,7 +172,7 @@ func (c *Comparer) compareFiles(ctx context.Context, f1, f2 fs.File, fname strin
 		oldFile := filepath.Join(c.tmpDir, oldName)
 
 		if err := c.downloadFile(ctx, f1, oldFile); err != nil {
-			return fmt.Errorf("error downloading old file: %v", err)
+			return errors.Wrap(err, "error downloading old file")
 		}
 
 		defer os.Remove(oldFile) //nolint:errcheck
@@ -182,7 +183,7 @@ func (c *Comparer) compareFiles(ctx context.Context, f1, f2 fs.File, fname strin
 		newFile := filepath.Join(c.tmpDir, newName)
 
 		if err := c.downloadFile(ctx, f2, newFile); err != nil {
-			return fmt.Errorf("error downloading new file: %v", err)
+			return errors.Wrap(err, "error downloading new file")
 		}
 		defer os.Remove(newFile) //nolint:errcheck
 	}

internal/editor/editor.go

@@ -3,6 +3,7 @@
 
 import (
 	"bufio"
+	"errors"
 	"fmt"
 	"io/ioutil"
 	"os"
@@ -52,7 +53,7 @@ func EditLoop(fname string, initial string, parse func(updated string) error) er
 		var shouldReopen string
 		fmt.Scanf("%s", &shouldReopen) //nolint:errcheck
 		if strings.HasPrefix(strings.ToLower(shouldReopen), "n") {
-			return fmt.Errorf("aborted")
+			return errors.New("aborted")
 		}
 	}
 }

internal/server/server.go

@@ -3,7 +3,6 @@
 import (
 	"context"
 	"encoding/json"
-	"fmt"
 	"net/http"
 	"net/url"
 	"sync"
@@ -13,6 +12,7 @@
 	"github.com/kopia/kopia/internal/serverapi"
 	"github.com/kopia/kopia/snapshot"
 	"github.com/kopia/repo"
+	"github.com/pkg/errors"
 )
 
 var log = kopialogging.Logger("kopia/server")
@@ -130,7 +130,7 @@ func New(ctx context.Context, rep *repo.Repository, hostname string, username st
 
 	sources, err := snapshot.ListSources(ctx, rep)
 	if err != nil {
-		return nil, fmt.Errorf("unable to list sources: %v", err)
+		return nil, errors.Wrap(err, "unable to list sources")
 	}
 
 	for _, src := range sources {

internal/serverapi/client.go

@@ -5,6 +5,8 @@
 	"encoding/json"
 	"fmt"
 	"net/http"
+
+	"github.com/pkg/errors"
 )
 
 // Client provides helper methods for communicating with Kopia API serevr.
@@ -25,7 +27,7 @@ func (c *Client) Get(path string, respPayload interface{}) error {
 		return fmt.Errorf("invalid server response: %v", resp.Status)
 	}
 	if err := json.NewDecoder(resp.Body).Decode(respPayload); err != nil {
-		return fmt.Errorf("malformed server response: %v", err)
+		return errors.Wrap(err, "malformed server response")
 	}
 
 	return nil
@@ -36,7 +38,7 @@ func (c *Client) Post(path string, reqPayload, respPayload interface{}) error {
 	var buf bytes.Buffer
 
 	if err := json.NewEncoder(&buf).Encode(reqPayload); err != nil {
-		return fmt.Errorf("unable to encode request: %v", err)
+		return errors.Wrap(err, "unable to encode request")
 	}
 
 	resp, err := c.client.Post(c.baseURL+path, "application/json", &buf)
@@ -49,7 +51,7 @@ func (c *Client) Post(path string, reqPayload, respPayload interface{}) error {
 		return fmt.Errorf("invalid server response: %v", resp.Status)
 	}
 	if err := json.NewDecoder(resp.Body).Decode(respPayload); err != nil {
-		return fmt.Errorf("malformed server response: %v", err)
+		return errors.Wrap(err, "malformed server response")
 	}
 
 	return nil

internal/webdavmount/webdavmount.go

@@ -1,7 +1,6 @@
 package webdavmount
 
 import (
-	"errors"
 	"fmt"
 	"os"
 	"strings"
@@ -9,6 +8,7 @@
 
 	"github.com/kopia/kopia/fs"
 	"github.com/kopia/kopia/internal/kopialogging"
+	"github.com/pkg/errors"
 	"golang.org/x/net/context"
 	"golang.org/x/net/webdav"
 )
@@ -177,7 +177,7 @@ func (w *webdavFS) findEntry(ctx context.Context, path string) (fs.Entry, error)
 	for i, p := range parts {
 		d, ok := e.(fs.Directory)
 		if !ok {
-			return nil, fmt.Errorf("%q not found in %q (not a directory)", p, strings.Join(parts[0:i], "/"))
+			return nil, errors.Errorf("%q not found in %q (not a directory)", p, strings.Join(parts[0:i], "/"))
 		}
 
 		entries, err := d.Readdir(ctx)
@@ -187,7 +187,7 @@ func (w *webdavFS) findEntry(ctx context.Context, path string) (fs.Entry, error)
 
 		e = entries.FindByName(p)
 		if e == nil {
-			return nil, fmt.Errorf("%q not found in %q (not found)", p, strings.Join(parts[0:i], "/"))
+			return nil, errors.Errorf("%q not found in %q (not found)", p, strings.Join(parts[0:i], "/"))
 		}
 	}
 

site/cli2md/cli2md.go

@@ -12,6 +12,7 @@
 
 	"github.com/kopia/kopia/cli"
 	_ "github.com/kopia/kopia/internal/logfile"
+	"github.com/pkg/errors"
 	"gopkg.in/alecthomas/kingpin.v2"
 )
 
@@ -111,7 +112,7 @@ func emitArgs(w io.Writer, args []*kingpin.ArgModel) {
 func generateAppFlags(app *kingpin.ApplicationModel) error {
 	f, err := os.Create(filepath.Join(baseDir, "flags.md"))
 	if err != nil {
-		return fmt.Errorf("unable to create common flags file: %v", err)
+		return errors.Wrap(err, "unable to create common flags file")
 	}
 	defer f.Close()
 
@@ -133,7 +134,7 @@ func generateCommands(app *kingpin.ApplicationModel, section string, weight int,
 	}
 	f, err := os.Create(filepath.Join(dir, "_index.md"))
 	if err != nil {
-		return fmt.Errorf("unable to create common flags file: %v", err)
+		return errors.Wrap(err, "unable to create common flags file")
 	}
 	defer f.Close()
 

snapshot/manager.go

@@ -3,11 +3,11 @@
 
 import (
 	"context"
-	"fmt"
 
 	"github.com/kopia/kopia/internal/kopialogging"
 	"github.com/kopia/repo"
 	"github.com/kopia/repo/manifest"
+	"github.com/pkg/errors"
 )
 
 var log = kopialogging.Logger("kopia/snapshot")
@@ -18,7 +18,7 @@ func ListSources(ctx context.Context, rep *repo.Repository) ([]SourceInfo, error
 		"type": "snapshot",
 	})
 	if err != nil {
-		return nil, fmt.Errorf("unable to find manifest entries: %v", err)
+		return nil, errors.Wrap(err, "unable to find manifest entries")
 	}
 
 	uniq := map[SourceInfo]bool{}
@@ -51,7 +51,7 @@ func sourceInfoToLabels(si SourceInfo) map[string]string {
 func ListSnapshots(ctx context.Context, rep *repo.Repository, si SourceInfo) ([]*Manifest, error) {
 	entries, err := rep.Manifests.Find(ctx, sourceInfoToLabels(si))
 	if err != nil {
-		return nil, fmt.Errorf("unable to find manifest entries: %v", err)
+		return nil, errors.Wrap(err, "unable to find manifest entries")
 	}
 	return LoadSnapshots(ctx, rep, entryIDs(entries))
 }
@@ -60,7 +60,7 @@ func ListSnapshots(ctx context.Context, rep *repo.Repository, si SourceInfo) ([]
 func loadSnapshot(ctx context.Context, rep *repo.Repository, manifestID string) (*Manifest, error) {
 	sm := &Manifest{}
 	if err := rep.Manifests.Get(ctx, manifestID, sm); err != nil {
-		return nil, fmt.Errorf("unable to find manifest entries: %v", err)
+		return nil, errors.Wrap(err, "unable to find manifest entries")
 	}
 
 	sm.ID = manifestID
@@ -70,13 +70,13 @@ func loadSnapshot(ctx context.Context, rep *repo.Repository, manifestID string)
 // SaveSnapshot persists given snapshot manifest and returns manifest ID.
 func SaveSnapshot(ctx context.Context, rep *repo.Repository, manifest *Manifest) (string, error) {
 	if manifest.Source.Host == "" {
-		return "", fmt.Errorf("missing host")
+		return "", errors.New("missing host")
 	}
 	if manifest.Source.UserName == "" {
-		return "", fmt.Errorf("missing username")
+		return "", errors.New("missing username")
 	}
 	if manifest.Source.Path == "" {
-		return "", fmt.Errorf("missing path")
+		return "", errors.New("missing path")
 	}
 
 	id, err := rep.Manifests.Put(ctx, sourceInfoToLabels(manifest.Source), manifest)
@@ -133,7 +133,7 @@ func ListSnapshotManifests(ctx context.Context, rep *repo.Repository, src *Sourc
 
 	entries, err := rep.Manifests.Find(ctx, labels)
 	if err != nil {
-		return nil, fmt.Errorf("unable to find manifest entries: %v", err)
+		return nil, errors.Wrap(err, "unable to find manifest entries")
 	}
 	return entryIDs(entries), nil
 }

snapshot/policy/policy_manager.go

@@ -12,6 +12,7 @@
 	"github.com/kopia/kopia/snapshot"
 	"github.com/kopia/repo"
 	"github.com/kopia/repo/manifest"
+	"github.com/pkg/errors"
 )
 
 // GlobalPolicySourceInfo is a source where global policy is attached.
@@ -83,7 +84,7 @@ func GetEffectivePolicy(ctx context.Context, rep *repo.Repository, si snapshot.S
 func GetDefinedPolicy(ctx context.Context, rep *repo.Repository, si snapshot.SourceInfo) (*Policy, error) {
 	md, err := rep.Manifests.Find(ctx, labelsForSource(si))
 	if err != nil {
-		return nil, fmt.Errorf("unable to find policy for source: %v", err)
+		return nil, errors.Wrap(err, "unable to find policy for source")
 	}
 
 	if len(md) == 0 {
@@ -111,7 +112,7 @@ func GetDefinedPolicy(ctx context.Context, rep *repo.Repository, si snapshot.Sou
 		return p, nil
 	}
 
-	return nil, fmt.Errorf("ambiguous policy")
+	return nil, errors.New("ambiguous policy")
 }
 
 // SetPolicy sets the policy on a given source.
@@ -127,7 +128,7 @@ func SetPolicy(ctx context.Context, rep *repo.Repository, si snapshot.SourceInfo
 
 	for _, em := range md {
 		if err := rep.Manifests.Delete(ctx, em.ID); err != nil {
-			return fmt.Errorf("unable to delete previous policy manifest: %v", err)
+			return errors.Wrap(err, "unable to delete previous policy manifest")
 		}
 	}
 
@@ -143,7 +144,7 @@ func RemovePolicy(ctx context.Context, rep *repo.Repository, si snapshot.SourceI
 
 	for _, em := range md {
 		if err := rep.Manifests.Delete(ctx, em.ID); err != nil {
-			return fmt.Errorf("unable to delete previous manifest: %v", err)
+			return errors.Wrap(err, "unable to delete previous manifest")
 		}
 	}
 
@@ -168,7 +169,7 @@ func ListPolicies(ctx context.Context, rep *repo.Repository) ([]*Policy, error)
 		"type": "policy",
 	})
 	if err != nil {
-		return nil, fmt.Errorf("unable to list manifests: %v", err)
+		return nil, errors.Wrap(err, "unable to list manifests")
 	}
 
 	var policies []*Policy
@@ -231,7 +232,7 @@ func FilesPolicyGetter(ctx context.Context, rep *repo.Repository, si snapshot.So
 
 		rel, err := filepath.Rel(si.Path, policyPath)
 		if err != nil {
-			return nil, fmt.Errorf("unable to determine relative path: %v", err)
+			return nil, errors.Wrap(err, "unable to determine relative path")
 		}
 		rel = "./" + rel
 		log.Debugf("loading policy for %v (%v)", policyPath, rel)

snapshot/policy/scheduling_policy.go

@@ -4,6 +4,8 @@
 	"fmt"
 	"sort"
 	"time"
+
+	"github.com/pkg/errors"
 )
 
 // TimeOfDay represents the time of day (hh:mm) using 24-hour time format.
@@ -15,7 +17,7 @@ type TimeOfDay struct {
 // Parse parses the time of day.
 func (t *TimeOfDay) Parse(s string) error {
 	if _, err := fmt.Sscanf(s, "%v:%02v", &t.Hour, &t.Minute); err != nil {
-		return fmt.Errorf("invalid time of day, must be HH:MM")
+		return errors.New("invalid time of day, must be HH:MM")
 	}
 	if t.Hour < 0 || t.Hour > 23 {
 		return fmt.Errorf("invalid hour %q, must be between 0 and 23", s)

snapshot/snapshotfs/repofs.go

@@ -12,6 +12,7 @@
 	"github.com/kopia/kopia/snapshot"
 	"github.com/kopia/repo"
 	"github.com/kopia/repo/object"
+	"github.com/pkg/errors"
 )
 
 type repositoryEntry struct {
@@ -181,7 +182,7 @@ func DirectoryEntry(rep *repo.Repository, objectID object.ID, dirSummary *fs.Dir
 func SnapshotRoot(rep *repo.Repository, man *snapshot.Manifest) (fs.Entry, error) {
 	oid := man.RootObjectID()
 	if oid == "" {
-		return nil, fmt.Errorf("manifest root object ID")
+		return nil, errors.New("manifest root object ID")
 	}
 
 	return newRepoEntry(rep, man.RootEntry), nil

snapshot/snapshotfs/upload.go

@@ -4,7 +4,6 @@
 	"bytes"
 	"context"
 	"encoding/binary"
-	"errors"
 	"fmt"
 	"hash/fnv"
 	"io"
@@ -22,6 +21,7 @@
 	"github.com/kopia/kopia/snapshot"
 	"github.com/kopia/repo"
 	"github.com/kopia/repo/object"
+	"github.com/pkg/errors"
 )
 
 var log = kopialogging.Logger("kopia/upload")
@@ -103,7 +103,7 @@ func (u *Uploader) cancelReason() string {
 func (u *Uploader) uploadFileInternal(ctx context.Context, f fs.File, relativePath string) entryResult {
 	file, err := f.Open(ctx)
 	if err != nil {
-		return entryResult{err: fmt.Errorf("unable to open file: %v", err)}
+		return entryResult{err: errors.Wrap(err, "unable to open file")}
 	}
 	defer file.Close() //nolint:errcheck
 
@@ -136,7 +136,7 @@ func (u *Uploader) uploadFileInternal(ctx context.Context, f fs.File, relativePa
 func (u *Uploader) uploadSymlinkInternal(ctx context.Context, f fs.Symlink, relativePath string) entryResult {
 	target, err := f.Readlink(ctx)
 	if err != nil {
-		return entryResult{err: fmt.Errorf("unable to read symlink: %v", err)}
+		return entryResult{err: errors.Wrap(err, "unable to read symlink")}
 	}
 
 	writer := u.repo.Objects.NewWriter(ctx, object.WriterOptions{
@@ -340,7 +340,7 @@ func (u *Uploader) processSubdirectories(ctx context.Context, relativePath strin
 		de := newDirEntry(dir, oid)
 		de.DirSummary = &subdirsumm
 		if err := dw.WriteEntry(de); err != nil {
-			return fmt.Errorf("unable to write dir entry: %v", err)
+			return errors.Wrap(err, "unable to write dir entry")
 		}
 
 		return nil
@@ -514,7 +514,7 @@ func (u *Uploader) processUploadWorkItems(workItems []*uploadWorkItem, dw *dirWr
 		}
 
 		if err := dw.WriteEntry(result.de); err != nil {
-			return fmt.Errorf("unable to write directory entry: %v", err)
+			return errors.Wrap(err, "unable to write directory entry")
 		}
 
 		if result.hash != 0 && it.entry.ModTime().Before(u.hashCacheCutoff) {
@@ -523,7 +523,7 @@ func (u *Uploader) processUploadWorkItems(workItems []*uploadWorkItem, dw *dirWr
 				Hash:     result.hash,
 				ObjectID: result.de.ObjectID,
 			}); err != nil {
-				return fmt.Errorf("unable to write hash cache entry: %v", err)
+				return errors.Wrap(err, "unable to write hash cache entry")
 			}
 		}
 	}
@@ -578,7 +578,7 @@ func uploadDirInternal(
 		return "", fs.DirectorySummary{}, err
 	}
 	if err := dw.Finalize(&summ); err != nil {
-		return "", fs.DirectorySummary{}, fmt.Errorf("unable to finalize directory: %v", err)
+		return "", fs.DirectorySummary{}, errors.Wrap(err, "unable to finalize directory")
 	}
 
 	oid, err := writer.Result()

snapshot/snapshotfs/upload_test.go

@@ -2,7 +2,6 @@
 
 import (
 	"context"
-	"fmt"
 	"io/ioutil"
 	"os"
 	"path/filepath"
@@ -14,6 +13,7 @@
 	"github.com/kopia/repo"
 	"github.com/kopia/repo/object"
 	"github.com/kopia/repo/storage/filesystem"
+	"github.com/pkg/errors"
 )
 
 const masterPassword = "foofoofoofoofoofoofoofoo"
@@ -24,7 +24,7 @@ type uploadTestHarness struct {
 	repo      *repo.Repository
 }
 
-var errTest = fmt.Errorf("test error")
+var errTest = errors.New("test error")
 
 func (th *uploadTestHarness) cleanup() {
 	os.RemoveAll(th.repoDir)