lint: work nicely with wrapped errors (errorlint)

Error wrapping as introduced in Go 1.13 adds some additional logic to
use for comparing errors and adding information to it.

Signed-off-by: Moritz Poldrack <moritz@poldrack.dev>
Acked-by: Robin Jarry <robin@jarry.cc>

commands/move-tab.go

@@ -31,7 +31,7 @@ func (MoveTab) Execute(aerc *widgets.Aerc, args []string) error {
 
 	n, err := strconv.Atoi(joinedArgs)
 	if err != nil {
-		return fmt.Errorf("failed to parse index argument: %v", err)
+		return fmt.Errorf("failed to parse index argument: %w", err)
 	}
 
 	var relative bool

commands/msg/forward.go

@@ -85,7 +85,7 @@ func (forward) Execute(aerc *widgets.Aerc, args []string) error {
 	if strings.Contains(to, "@") {
 		tolist, err = mail.ParseAddressList(to)
 		if err != nil {
-			return fmt.Errorf("invalid to address(es): %v", err)
+			return fmt.Errorf("invalid to address(es): %w", err)
 		}
 	}
 	if len(tolist) > 0 {

completer/completer.go

@@ -2,6 +2,7 @@ package completer
 
 import (
 	"bufio"
+	"errors"
 	"fmt"
 	"io"
 	"io/ioutil"
@@ -82,14 +83,14 @@ func (c *Completer) completeAddress(s string) ([]string, string, error) {
 	}
 	stdout, err := cmd.StdoutPipe()
 	if err != nil {
-		return nil, "", fmt.Errorf("stdout: %v", err)
+		return nil, "", fmt.Errorf("stdout: %w", err)
 	}
 	stderr, err := cmd.StderrPipe()
 	if err != nil {
-		return nil, "", fmt.Errorf("stderr: %v", err)
+		return nil, "", fmt.Errorf("stderr: %w", err)
 	}
 	if err := cmd.Start(); err != nil {
-		return nil, "", fmt.Errorf("cmd start: %v", err)
+		return nil, "", fmt.Errorf("cmd start: %w", err)
 	}
 	// Wait returns an error if the exit status != 0, which some completion
 	// programs will do to signal no matches. We don't want to spam the user with
@@ -104,7 +105,7 @@ func (c *Completer) completeAddress(s string) ([]string, string, error) {
 		if msg != "" {
 			msg = ": " + msg
 		}
-		return nil, "", fmt.Errorf("read completions%s: %v", msg, err)
+		return nil, "", fmt.Errorf("read completions%s: %w", msg, err)
 	}
 
 	return completions, prefix, nil
@@ -150,7 +151,7 @@ func readCompletions(r io.Reader) ([]string, error) {
 	completions := []string{}
 	for {
 		line, err := buf.ReadString('\n')
-		if err == io.EOF {
+		if errors.Is(err, io.EOF) {
 			return completions, nil
 		} else if err != nil {
 			return nil, err

config/config.go

@@ -128,7 +128,7 @@ func (c RemoteConfig) ConnectionString() (string, error) {
 	cmd.Stdin = os.Stdin
 	output, err := cmd.Output()
 	if err != nil {
-		return "", fmt.Errorf("failed to read password: %s", err)
+		return "", fmt.Errorf("failed to read password: %w", err)
 	}
 
 	pw := strings.TrimSpace(string(output))
@@ -344,13 +344,13 @@ func loadAccountConfig(path string) ([]AccountConfig, error) {
 
 		source, err := sourceRemoteConfig.ConnectionString()
 		if err != nil {
-			return nil, fmt.Errorf("Invalid source credentials for %s: %s", _sec, err)
+			return nil, fmt.Errorf("Invalid source credentials for %s: %w", _sec, err)
 		}
 		account.Source = source
 
 		_, err = account.Outgoing.parseValue()
 		if err != nil {
-			return nil, fmt.Errorf("Invalid outgoing credentials for %s: %s", _sec, err)
+			return nil, fmt.Errorf("Invalid outgoing credentials for %s: %w", _sec, err)
 		}
 
 		accounts = append(accounts, account)
@@ -1027,7 +1027,7 @@ func (ui *UIConfig) loadStyleSet(styleSetDirs []string) error {
 	ui.style = NewStyleSet()
 	err := ui.style.LoadStyleSet(ui.StyleSetName, styleSetDirs)
 	if err != nil {
-		return fmt.Errorf("Unable to load default styleset: %s", err)
+		return fmt.Errorf("Unable to load default styleset: %w", err)
 	}
 
 	return nil

lib/crypto/gpg/gpgbin/encrypt.go

@@ -33,7 +33,7 @@ func Encrypt(r io.Reader, to []string, from string) ([]byte, error) {
 	var md models.MessageDetails
 	err = parse(outRdr, &md)
 	if err != nil {
-		return nil, fmt.Errorf("gpg: failure to encrypt: %v. check public key(s)", err)
+		return nil, fmt.Errorf("gpg: failure to encrypt: %w. check public key(s)", err)
 	}
 	var buf bytes.Buffer
 	_, _ = io.Copy(&buf, md.Body)

lib/crypto/gpg/gpgbin/sign.go

@@ -26,7 +26,7 @@ func Sign(r io.Reader, from string) ([]byte, string, error) {
 	var md models.MessageDetails
 	err = parse(outRdr, &md)
 	if err != nil {
-		return nil, "", fmt.Errorf("failed to parse messagedetails: %v", err)
+		return nil, "", fmt.Errorf("failed to parse messagedetails: %w", err)
 	}
 	var buf bytes.Buffer
 	_, _ = io.Copy(&buf, md.Body)

lib/crypto/gpg/reader.go

@@ -61,12 +61,12 @@ func Read(r io.Reader) (*Reader, error) {
 func newEncryptedReader(h textproto.Header, mr *textproto.MultipartReader) (*Reader, error) {
 	p, err := mr.NextPart()
 	if err != nil {
-		return nil, fmt.Errorf("gpgmail: failed to read first part in multipart/encrypted message: %v", err)
+		return nil, fmt.Errorf("gpgmail: failed to read first part in multipart/encrypted message: %w", err)
 	}
 
 	t, _, err := mime.ParseMediaType(p.Header.Get("Content-Type"))
 	if err != nil {
-		return nil, fmt.Errorf("gpgmail: failed to parse Content-Type of first part in multipart/encrypted message: %v", err)
+		return nil, fmt.Errorf("gpgmail: failed to parse Content-Type of first part in multipart/encrypted message: %w", err)
 	}
 	if !strings.EqualFold(t, "application/pgp-encrypted") {
 		return nil, fmt.Errorf("gpgmail: first part in multipart/encrypted message has type %q, not application/pgp-encrypted", t)
@@ -74,7 +74,7 @@ func newEncryptedReader(h textproto.Header, mr *textproto.MultipartReader) (*Rea
 
 	metadata, err := textproto.ReadHeader(bufio.NewReader(p))
 	if err != nil {
-		return nil, fmt.Errorf("gpgmail: failed to parse application/pgp-encrypted part: %v", err)
+		return nil, fmt.Errorf("gpgmail: failed to parse application/pgp-encrypted part: %w", err)
 	}
 	if s := metadata.Get("Version"); s != "1" {
 		return nil, fmt.Errorf("gpgmail: unsupported PGP/MIME version: %q", s)
@@ -82,11 +82,11 @@ func newEncryptedReader(h textproto.Header, mr *textproto.MultipartReader) (*Rea
 
 	p, err = mr.NextPart()
 	if err != nil {
-		return nil, fmt.Errorf("gpgmail: failed to read second part in multipart/encrypted message: %v", err)
+		return nil, fmt.Errorf("gpgmail: failed to read second part in multipart/encrypted message: %w", err)
 	}
 	t, _, err = mime.ParseMediaType(p.Header.Get("Content-Type"))
 	if err != nil {
-		return nil, fmt.Errorf("gpgmail: failed to parse Content-Type of second part in multipart/encrypted message: %v", err)
+		return nil, fmt.Errorf("gpgmail: failed to parse Content-Type of second part in multipart/encrypted message: %w", err)
 	}
 	if !strings.EqualFold(t, "application/octet-stream") {
 		return nil, fmt.Errorf("gpgmail: second part in multipart/encrypted message has type %q, not application/octet-stream", t)
@@ -94,13 +94,13 @@ func newEncryptedReader(h textproto.Header, mr *textproto.MultipartReader) (*Rea
 
 	md, err := gpgbin.Decrypt(p)
 	if err != nil {
-		return nil, fmt.Errorf("gpgmail: failed to read PGP message: %v", err)
+		return nil, fmt.Errorf("gpgmail: failed to read PGP message: %w", err)
 	}
 
 	cleartext := bufio.NewReader(md.Body)
 	cleartextHeader, err := textproto.ReadHeader(cleartext)
 	if err != nil {
-		return nil, fmt.Errorf("gpgmail: failed to read encrypted header: %v", err)
+		return nil, fmt.Errorf("gpgmail: failed to read encrypted header: %w", err)
 	}
 
 	t, params, err := mime.ParseMediaType(cleartextHeader.Get("Content-Type"))
@@ -114,7 +114,7 @@ func newEncryptedReader(h textproto.Header, mr *textproto.MultipartReader) (*Rea
 		mr := textproto.NewMultipartReader(cleartext, params["boundary"])
 		mds, err := newSignedReader(cleartextHeader, mr, micalg)
 		if err != nil {
-			return nil, fmt.Errorf("gpgmail: failed to read encapsulated multipart/signed message: %v", err)
+			return nil, fmt.Errorf("gpgmail: failed to read encapsulated multipart/signed message: %w", err)
 		}
 		mds.MessageDetails.IsEncrypted = md.IsEncrypted
 		mds.MessageDetails.DecryptedWith = md.DecryptedWith
@@ -136,7 +136,7 @@ func newSignedReader(h textproto.Header, mr *textproto.MultipartReader, micalg s
 	micalg = strings.ToLower(micalg)
 	p, err := mr.NextPart()
 	if err != nil {
-		return nil, fmt.Errorf("gpgmail: failed to read signed part in multipart/signed message: %v", err)
+		return nil, fmt.Errorf("gpgmail: failed to read signed part in multipart/signed message: %w", err)
 	}
 	var headerBuf bytes.Buffer
 	_ = textproto.WriteHeader(&headerBuf, p.Header)
@@ -147,12 +147,12 @@ func newSignedReader(h textproto.Header, mr *textproto.MultipartReader, micalg s
 
 	sig, err := mr.NextPart()
 	if err != nil {
-		return nil, fmt.Errorf("gpgmail: failed to read pgp part in multipart/signed message: %v", err)
+		return nil, fmt.Errorf("gpgmail: failed to read pgp part in multipart/signed message: %w", err)
 	}
 
 	md, err := gpgbin.Verify(&msg, sig)
 	if err != nil {
-		return nil, fmt.Errorf("gpgmail: failed to read PGP message: %v", err)
+		return nil, fmt.Errorf("gpgmail: failed to read PGP message: %w", err)
 	}
 	if md.Micalg != micalg && md.SignatureError == "" {
 		md.SignatureError = "gpg: header hash does not match actual sig hash"

lib/crypto/pgp/pgp.go

@@ -33,7 +33,7 @@ func (m *Mail) Init() error {
 	logging.Infof("Initializing PGP keyring")
 	err := os.MkdirAll(path.Join(xdg.DataHome(), "aerc"), 0o700)
 	if err != nil {
-		return fmt.Errorf("failed to create data directory: %v", err)
+		return fmt.Errorf("failed to create data directory: %w", err)
 	}
 
 	lockpath := path.Join(xdg.DataHome(), "aerc", "keyring.lock")
@@ -290,16 +290,16 @@ func (m *Mail) ExportKey(k string) (io.Reader, error) {
 	pks := bytes.NewBuffer(nil)
 	err = entity.Serialize(pks)
 	if err != nil {
-		return nil, fmt.Errorf("pgp: error exporting key: %v", err)
+		return nil, fmt.Errorf("pgp: error exporting key: %w", err)
 	}
 	pka := bytes.NewBuffer(nil)
 	w, err := armor.Encode(pka, "PGP PUBLIC KEY BLOCK", map[string]string{})
 	if err != nil {
-		return nil, fmt.Errorf("pgp: error exporting key: %v", err)
+		return nil, fmt.Errorf("pgp: error exporting key: %w", err)
 	}
 	_, err = w.Write(pks.Bytes())
 	if err != nil {
-		return nil, fmt.Errorf("pgp: error exporting key: %v", err)
+		return nil, fmt.Errorf("pgp: error exporting key: %w", err)
 	}
 	w.Close()
 	return pka, nil

lib/oauthbearer.go

@@ -23,7 +23,7 @@ func (c *OAuthBearer) ExchangeRefreshToken(refreshToken string) (*oauth2.Token,
 
 func (c *OAuthBearer) Authenticate(username string, password string, client *client.Client) error {
 	if ok, err := client.SupportAuth(sasl.OAuthBearer); err != nil || !ok {
-		return fmt.Errorf("OAuthBearer not supported %v", err)
+		return fmt.Errorf("OAuthBearer not supported %w", err)
 	}
 
 	if c.OAuth2.Endpoint.TokenURL != "" {

widgets/account.go

@@ -404,7 +404,7 @@ func (acct *AccountView) GetSortCriteria() []*types.SortCriterion {
 	}
 	criteria, err := sort.GetSortCriteria(acct.UiConfig().Sort)
 	if err != nil {
-		acct.PushError(fmt.Errorf("ui sort: %v", err))
+		acct.PushError(fmt.Errorf("ui sort: %w", err))
 		return nil
 	}
 	return criteria

widgets/aerc.go

@@ -536,7 +536,7 @@ func (aerc *Aerc) Mailto(addr *url.URL) error {
 	h := &mail.Header{}
 	to, err := mail.ParseAddressList(addr.Opaque)
 	if err != nil && addr.Opaque != "" {
-		return fmt.Errorf("Could not parse to: %v", err)
+		return fmt.Errorf("Could not parse to: %w", err)
 	}
 	h.SetAddressList("to", to)
 	for key, vals := range addr.Query() {

widgets/compose.go

@@ -202,7 +202,7 @@ func (c *Composer) SetAttachKey(attach bool) error {
 		if found {
 			err := c.DeleteAttachment(name)
 			if err != nil {
-				return fmt.Errorf("failed to delete attachment '%s: %v", name, err)
+				return fmt.Errorf("failed to delete attachment '%s: %w", name, err)
 			}
 		} else {
 			attach = !attach
@@ -259,7 +259,7 @@ func (c *Composer) SetSign(sign bool) error {
 	err := c.updateCrypto()
 	if err != nil {
 		c.sign = !sign
-		return fmt.Errorf("Cannot sign message: %v", err)
+		return fmt.Errorf("Cannot sign message: %w", err)
 	}
 	return nil
 }
@@ -403,7 +403,7 @@ func (c *Composer) AddTemplate(template string, data interface{}) error {
 
 	mr, err := mail.CreateReader(templateText)
 	if err != nil {
-		return fmt.Errorf("Template loading failed: %v", err)
+		return fmt.Errorf("Template loading failed: %w", err)
 	}
 
 	// copy the headers contained in the template to the compose headers
@@ -414,7 +414,7 @@ func (c *Composer) AddTemplate(template string, data interface{}) error {
 
 	part, err := mr.NextPart()
 	if err != nil {
-		return fmt.Errorf("Could not get body of template: %v", err)
+		return fmt.Errorf("Could not get body of template: %w", err)
 	}
 
 	c.AppendContents(part.Body)

worker/imap/configure.go

@@ -65,7 +65,7 @@ func (w *IMAPWorker) handleConfigure(msg *types.Configure) error {
 			val, err := time.ParseDuration(value)
 			if err != nil || val < 0 {
 				return fmt.Errorf(
-					"invalid idle-timeout value %v: %v",
+					"invalid idle-timeout value %v: %w",
 					value, err)
 			}
 			w.config.idle_timeout = val
@@ -73,7 +73,7 @@ func (w *IMAPWorker) handleConfigure(msg *types.Configure) error {
 			val, err := time.ParseDuration(value)
 			if err != nil || val < 0 {
 				return fmt.Errorf(
-					"invalid idle-debounce value %v: %v",
+					"invalid idle-debounce value %v: %w",
 					value, err)
 			}
 			w.config.idle_debounce = val
@@ -81,7 +81,7 @@ func (w *IMAPWorker) handleConfigure(msg *types.Configure) error {
 			val, err := time.ParseDuration(value)
 			if err != nil || val < 0 {
 				return fmt.Errorf(
-					"invalid reconnect-maxwait value %v: %v",
+					"invalid reconnect-maxwait value %v: %w",
 					value, err)
 			}
 			w.config.reconnect_maxwait = val
@@ -89,7 +89,7 @@ func (w *IMAPWorker) handleConfigure(msg *types.Configure) error {
 			val, err := time.ParseDuration(value)
 			if err != nil || val < 0 {
 				return fmt.Errorf(
-					"invalid connection-timeout value %v: %v",
+					"invalid connection-timeout value %v: %w",
 					value, err)
 			}
 			w.config.connection_timeout = val
@@ -97,7 +97,7 @@ func (w *IMAPWorker) handleConfigure(msg *types.Configure) error {
 			val, err := time.ParseDuration(value)
 			if err != nil || val < 0 {
 				return fmt.Errorf(
-					"invalid keepalive-period value %v: %v",
+					"invalid keepalive-period value %v: %w",
 					value, err)
 			}
 			w.config.keepalive_period = val
@@ -105,7 +105,7 @@ func (w *IMAPWorker) handleConfigure(msg *types.Configure) error {
 			val, err := strconv.Atoi(value)
 			if err != nil || val < 0 {
 				return fmt.Errorf(
-					"invalid keepalive-probes value %v: %v",
+					"invalid keepalive-probes value %v: %w",
 					value, err)
 			}
 			w.config.keepalive_probes = val
@@ -113,7 +113,7 @@ func (w *IMAPWorker) handleConfigure(msg *types.Configure) error {
 			val, err := time.ParseDuration(value)
 			if err != nil || val < 0 {
 				return fmt.Errorf(
-					"invalid keepalive-interval value %v: %v",
+					"invalid keepalive-interval value %v: %w",
 					value, err)
 			}
 			w.config.keepalive_interval = int(val.Seconds())
@@ -123,13 +123,13 @@ func (w *IMAPWorker) handleConfigure(msg *types.Configure) error {
 				// Return an error here because the user tried to set header
 				// caching, and we want them to know they didn't set it right -
 				// one way or the other
-				return fmt.Errorf("invalid cache-headers value %v: %v", value, err)
+				return fmt.Errorf("invalid cache-headers value %v: %w", value, err)
 			}
 			w.config.cacheEnabled = cache
 		case "cache-max-age":
 			val, err := time.ParseDuration(value)
 			if err != nil || val < 0 {
-				return fmt.Errorf("invalid cache-max-age value %v: %v", value, err)
+				return fmt.Errorf("invalid cache-max-age value %v: %w", value, err)
 			}
 			w.config.cacheMaxAge = val
 		}

worker/imap/fetch.go

@@ -118,13 +118,13 @@ func (imapw *IMAPWorker) handleFetchMessageBodyPart(
 			}
 			h, err := textproto.ReadHeader(bufio.NewReader(body))
 			if err != nil {
-				return fmt.Errorf("failed to read part header: %v", err)
+				return fmt.Errorf("failed to read part header: %w", err)
 			}
 
 			part, err := message.New(message.Header{Header: h},
 				_msg.GetBody(&partBodySection))
 			if err != nil {
-				return fmt.Errorf("failed to create message reader: %v", err)
+				return fmt.Errorf("failed to create message reader: %w", err)
 			}
 
 			imapw.worker.PostMessage(&types.MessageBodyPart{

worker/imap/worker.go

@@ -282,7 +282,7 @@ func (w *IMAPWorker) Run() {
 		case msg := <-w.worker.Actions:
 			msg = w.worker.ProcessAction(msg)
 
-			if err := w.handleMessage(msg); err == errUnsupported {
+			if err := w.handleMessage(msg); errors.Is(err, errUnsupported) {
 				w.worker.PostMessage(&types.Unsupported{
 					Message: types.RespondTo(msg),
 				}, nil)

worker/lib/parse.go

@@ -104,7 +104,7 @@ func ParseEntityStructure(e *message.Entity) (*models.BodyStructure, error) {
 	if cd := e.Header.Get("content-disposition"); cd != "" {
 		contentDisposition, cdParams, err := e.Header.ContentDisposition()
 		if err != nil {
-			return nil, fmt.Errorf("could not parse content disposition: %v", err)
+			return nil, fmt.Errorf("could not parse content disposition: %w", err)
 		}
 		body.Disposition = contentDisposition
 		body.DispositionParams = cdParams
@@ -113,7 +113,7 @@ func ParseEntityStructure(e *message.Entity) (*models.BodyStructure, error) {
 	if mpr := e.MultipartReader(); mpr != nil {
 		for {
 			part, err := mpr.NextPart()
-			if err == io.EOF {
+			if errors.Is(err, io.EOF) {
 				return &body, nil
 			} else if err != nil {
 				return nil, err
@@ -133,27 +133,27 @@ var DateParseError = errors.New("date parsing failed")
 func parseEnvelope(h *mail.Header) (*models.Envelope, error) {
 	from, err := parseAddressList(h, "from")
 	if err != nil {
-		return nil, fmt.Errorf("could not read from address: %v", err)
+		return nil, fmt.Errorf("could not read from address: %w", err)
 	}
 	to, err := parseAddressList(h, "to")
 	if err != nil {
-		return nil, fmt.Errorf("could not read to address: %v", err)
+		return nil, fmt.Errorf("could not read to address: %w", err)
 	}
 	cc, err := parseAddressList(h, "cc")
 	if err != nil {
-		return nil, fmt.Errorf("could not read cc address: %v", err)
+		return nil, fmt.Errorf("could not read cc address: %w", err)
 	}
 	bcc, err := parseAddressList(h, "bcc")
 	if err != nil {
-		return nil, fmt.Errorf("could not read bcc address: %v", err)
+		return nil, fmt.Errorf("could not read bcc address: %w", err)
 	}
 	replyTo, err := parseAddressList(h, "reply-to")
 	if err != nil {
-		return nil, fmt.Errorf("could not read reply-to address: %v", err)
+		return nil, fmt.Errorf("could not read reply-to address: %w", err)
 	}
 	subj, err := h.Subject()
 	if err != nil {
-		return nil, fmt.Errorf("could not read subject: %v", err)
+		return nil, fmt.Errorf("could not read subject: %w", err)
 	}
 	msgID, err := h.MessageID()
 	if err != nil {
@@ -167,7 +167,7 @@ func parseEnvelope(h *mail.Header) (*models.Envelope, error) {
 	if err != nil {
 		// still return a valid struct plus a sentinel date parsing error
 		// if only the date parsing failed
-		err = fmt.Errorf("%w: %v", DateParseError, err)
+		err = fmt.Errorf("%v: %w", DateParseError, err)
 	}
 	return &models.Envelope{
 		Date:      date,
@@ -217,7 +217,7 @@ func parseDate(h *mail.Header) (time.Time, error) {
 func parseReceivedHeader(h *mail.Header) (time.Time, error) {
 	guess, err := h.Text("received")
 	if err != nil {
-		return time.Time{}, fmt.Errorf("received header not parseable: %v",
+		return time.Time{}, fmt.Errorf("received header not parseable: %w",
 			err)
 	}
 	return time.Parse(time.RFC1123Z, dateRe.FindString(guess))
@@ -254,18 +254,18 @@ func MessageInfo(raw RawMessage) (*models.MessageInfo, error) {
 	defer r.Close()
 	msg, err := message.Read(r)
 	if err != nil {
-		return nil, fmt.Errorf("could not read message: %v", err)
+		return nil, fmt.Errorf("could not read message: %w", err)
 	}
 	bs, err := ParseEntityStructure(msg)
 	if errors.As(err, new(message.UnknownEncodingError)) {
 		parseErr = err
 	} else if err != nil {
-		return nil, fmt.Errorf("could not get structure: %v", err)
+		return nil, fmt.Errorf("could not get structure: %w", err)
 	}
 	h := &mail.Header{Header: msg.Header}
 	env, err := parseEnvelope(h)
 	if err != nil && !errors.Is(err, DateParseError) {
-		return nil, fmt.Errorf("could not parse envelope: %v", err)
+		return nil, fmt.Errorf("could not parse envelope: %w", err)
 		// if only the date parsing failed we still get the rest of the
 		// envelop structure in a valid state.
 		// Date parsing errors are fairly common and it's better to be

worker/maildir/container.go

@@ -50,7 +50,7 @@ func (c *Container) ListFolders() ([]string, error) {
 	}
 	err := filepath.Walk(c.dir, func(path string, info os.FileInfo, err error) error {
 		if err != nil {
-			return fmt.Errorf("Invalid path '%s': error: %v", path, err)
+			return fmt.Errorf("Invalid path '%s': error: %w", path, err)
 		}
 		if !info.IsDir() {
 			return nil
@@ -144,7 +144,7 @@ func (c *Container) ClearRecentFlag(uid uint32) {
 func (c *Container) UIDs(d maildir.Dir) ([]uint32, error) {
 	keys, err := d.Keys()
 	if err != nil {
-		return nil, fmt.Errorf("could not get keys for %s: %v", d, err)
+		return nil, fmt.Errorf("could not get keys for %s: %w", d, err)
 	}
 	sort.Strings(keys)
 	var uids []uint32
@@ -189,7 +189,7 @@ func (c *Container) CopyAll(
 ) error {
 	for _, uid := range uids {
 		if err := c.copyMessage(dest, src, uid); err != nil {
-			return fmt.Errorf("could not copy message %d: %v", uid, err)
+			return fmt.Errorf("could not copy message %d: %w", uid, err)
 		}
 	}
 	return nil

worker/maildir/message.go

@@ -46,7 +46,7 @@ func (m Message) SetFlags(flags []maildir.Flag) error {
 func (m Message) SetOneFlag(flag maildir.Flag, enable bool) error {
 	flags, err := m.Flags()
 	if err != nil {
-		return fmt.Errorf("could not read previous flags: %v", err)
+		return fmt.Errorf("could not read previous flags: %w", err)
 	}
 	if enable {
 		flags = append(flags, flag)
@@ -87,7 +87,7 @@ func (m Message) NewBodyPartReader(requestedParts []int) (io.Reader, error) {
 	defer f.Close()
 	msg, err := message.Read(f)
 	if err != nil {
-		return nil, fmt.Errorf("could not read message: %v", err)
+		return nil, fmt.Errorf("could not read message: %w", err)
 	}
 	return lib.FetchEntityPartReader(msg, requestedParts)
 }

worker/maildir/worker.go

@@ -46,7 +46,7 @@ type Worker struct {
 func NewWorker(worker *types.Worker) (types.Backend, error) {
 	watch, err := fsnotify.NewWatcher()
 	if err != nil {
-		return nil, fmt.Errorf("could not create file system watcher: %v", err)
+		return nil, fmt.Errorf("could not create file system watcher: %w", err)
 	}
 	return &Worker{worker: worker, watcher: watch}, nil
 }
@@ -55,7 +55,7 @@ func NewWorker(worker *types.Worker) (types.Backend, error) {
 func NewMaildirppWorker(worker *types.Worker) (types.Backend, error) {
 	watch, err := fsnotify.NewWatcher()
 	if err != nil {
-		return nil, fmt.Errorf("could not create file system watcher: %v", err)
+		return nil, fmt.Errorf("could not create file system watcher: %w", err)
 	}
 	return &Worker{worker: worker, watcher: watch, maildirpp: true}, nil
 }
@@ -112,18 +112,18 @@ func (w *Worker) handleFSEvent(ev fsnotify.Event) {
 	}
 	err := w.c.SyncNewMail(*w.selected)
 	if err != nil {
-		logging.Errorf("could not move new to cur : %v", err)
+		logging.Errorf("could not move new to cur : %w", err)
 		return
 	}
 
 	uids, err := w.c.UIDs(*w.selected)
 	if err != nil {
-		logging.Errorf("could not scan UIDs: %v", err)
+		logging.Errorf("could not scan UIDs: %w", err)
 		return
 	}
 	sortedUids, err := w.sort(uids, w.currentSortCriteria)
 	if err != nil {
-		logging.Errorf("error sorting directory: %v", err)
+		logging.Errorf("error sorting directory: %w", err)
 		return
 	}
 	w.worker.PostMessage(&types.DirectoryContents{
@@ -204,18 +204,18 @@ func (w *Worker) getDirectoryInfo(name string) *models.DirectoryInfo {
 		for _, v := range files {
 			key, flags, err := splitMaildirFile(v)
 			if err != nil {
-				logging.Errorf("%q: error parsing flags (%q): %v", v, key, err)
+				logging.Errorf("%q: error parsing flags (%q): %w", v, key, err)
 				continue
 			}
 			keyFlags[key] = flags
 		}
 	} else {
-		logging.Infof("disabled flags cache: %q: %v", dir, err)
+		logging.Infof("disabled flags cache: %q: %w", dir, err)
 	}
 
 	uids, err := w.c.UIDs(dir)
 	if err != nil {
-		logging.Errorf("could not get uids: %v", err)
+		logging.Errorf("could not get uids: %w", err)
 		return dirInfo
 	}
 
@@ -223,7 +223,7 @@ func (w *Worker) getDirectoryInfo(name string) *models.DirectoryInfo {
 	for _, uid := range uids {
 		message, err := w.c.Message(dir, uid)
 		if err != nil {
-			logging.Errorf("could not get message: %v", err)
+			logging.Errorf("could not get message: %w", err)
 			continue
 		}
 		var flags []maildir.Flag
@@ -234,14 +234,14 @@ func (w *Worker) getDirectoryInfo(name string) *models.DirectoryInfo {
 				logging.Debugf("message (key=%q uid=%d) not found in map cache", message.key, message.uid)
 				flags, err = message.Flags()
 				if err != nil {
-					logging.Errorf("could not get flags: %v", err)
+					logging.Errorf("could not get flags: %w", err)
 					continue
 				}
 			}
 		} else {
 			flags, err = message.Flags()
 			if err != nil {
-				logging.Errorf("could not get flags: %v", err)
+				logging.Errorf("could not get flags: %w", err)
 				continue
 			}
 		}
@@ -306,14 +306,14 @@ func (w *Worker) handleMessage(msg types.WorkerMessage) error {
 func (w *Worker) handleConfigure(msg *types.Configure) error {
 	u, err := url.Parse(msg.Config.Source)
 	if err != nil {
-		logging.Errorf("error configuring maildir worker: %v", err)
+		logging.Errorf("error configuring maildir worker: %w", err)
 		return err
 	}
 	dir := u.Path
 	if u.Host == "~" {
 		home, err := os.UserHomeDir()
 		if err != nil {
-			return fmt.Errorf("could not resolve home directory: %v", err)
+			return fmt.Errorf("could not resolve home directory: %w", err)
 		}
 		dir = filepath.Join(home, u.Path)
 	}
@@ -343,7 +343,7 @@ func (w *Worker) handleListDirectories(msg *types.ListDirectories) error {
 	}
 	dirs, err := w.c.ListFolders()
 	if err != nil {
-		logging.Errorf("failed listing directories: %v", err)
+		logging.Errorf("failed listing directories: %w", err)
 		return err
 	}
 	for _, name := range dirs {
@@ -375,11 +375,11 @@ func (w *Worker) handleOpenDirectory(msg *types.OpenDirectory) error {
 	if w.selected != nil {
 		prevDir := filepath.Join(string(*w.selected), "new")
 		if err := w.watcher.Remove(prevDir); err != nil {
-			return fmt.Errorf("could not unwatch previous directory: %v", err)
+			return fmt.Errorf("could not unwatch previous directory: %w", err)
 		}
 		prevDir = filepath.Join(string(*w.selected), "cur")
 		if err := w.watcher.Remove(prevDir); err != nil {
-			return fmt.Errorf("could not unwatch previous directory: %v", err)
+			return fmt.Errorf("could not unwatch previous directory: %w", err)
 		}
 	}
 
@@ -389,15 +389,15 @@ func (w *Worker) handleOpenDirectory(msg *types.OpenDirectory) error {
 	// add watch paths
 	newDir := filepath.Join(string(*w.selected), "new")
 	if err := w.watcher.Add(newDir); err != nil {
-		return fmt.Errorf("could not add watch to directory: %v", err)
+		return fmt.Errorf("could not add watch to directory: %w", err)
 	}
 	newDir = filepath.Join(string(*w.selected), "cur")
 	if err := w.watcher.Add(newDir); err != nil {
-		return fmt.Errorf("could not add watch to directory: %v", err)
+		return fmt.Errorf("could not add watch to directory: %w", err)
 	}
 
 	if err := dir.Clean(); err != nil {
-		return fmt.Errorf("could not clean directory: %v", err)
+		return fmt.Errorf("could not clean directory: %w", err)
 	}
 
 	info := &types.DirectoryInfo{
@@ -426,13 +426,13 @@ func (w *Worker) handleFetchDirectoryContents(
 	} else {
 		uids, err = w.c.UIDs(*w.selected)
 		if err != nil {
-			logging.Errorf("failed scanning uids: %v", err)
+			logging.Errorf("failed scanning uids: %w", err)
 			return err
 		}
 	}
 	sortedUids, err := w.sort(uids, msg.SortCriteria)
 	if err != nil {
-		logging.Errorf("failed sorting directory: %v", err)
+		logging.Errorf("failed sorting directory: %w", err)
 		return err
 	}
 	w.currentSortCriteria = msg.SortCriteria
@@ -451,14 +451,14 @@ func (w *Worker) sort(uids []uint32, criteria []*types.SortCriterion) ([]uint32,
 	for _, uid := range uids {
 		info, err := w.msgInfoFromUid(uid)
 		if err != nil {
-			logging.Errorf("could not get message info: %v", err)
+			logging.Errorf("could not get message info: %w", err)
 			continue
 		}
 		msgInfos = append(msgInfos, info)
 	}
 	sortedUids, err := lib.Sort(msgInfos, criteria)
 	if err != nil {
-		logging.Errorf("could not sort the messages: %v", err)
+		logging.Errorf("could not sort the messages: %w", err)
 		return nil, err
 	}
 	return sortedUids, nil
@@ -467,7 +467,7 @@ func (w *Worker) sort(uids []uint32, criteria []*types.SortCriterion) ([]uint32,
 func (w *Worker) handleCreateDirectory(msg *types.CreateDirectory) error {
 	dir := w.c.Dir(msg.Directory)
 	if err := dir.Init(); err != nil {
-		logging.Errorf("could not create directory %s: %v",
+		logging.Errorf("could not create directory %s: %w",
 			msg.Directory, err)
 		return err
 	}
@@ -477,7 +477,7 @@ func (w *Worker) handleCreateDirectory(msg *types.CreateDirectory) error {
 func (w *Worker) handleRemoveDirectory(msg *types.RemoveDirectory) error {
 	dir := w.c.Dir(msg.Directory)
 	if err := os.RemoveAll(string(dir)); err != nil {
-		logging.Errorf("could not remove directory %s: %v",
+		logging.Errorf("could not remove directory %s: %w",
 			msg.Directory, err)
 		return err
 	}
@@ -490,7 +490,7 @@ func (w *Worker) handleFetchMessageHeaders(
 	for _, uid := range msg.Uids {
 		info, err := w.msgInfoFromUid(uid)
 		if err != nil {
-			logging.Errorf("could not get message info: %v", err)
+			logging.Errorf("could not get message info: %w", err)
 			w.err(msg, err)
 			continue
 		}
@@ -509,13 +509,13 @@ func (w *Worker) handleFetchMessageBodyPart(
 	// get reader
 	m, err := w.c.Message(*w.selected, msg.Uid)
 	if err != nil {
-		logging.Errorf("could not get message %d: %v", msg.Uid, err)
+		logging.Errorf("could not get message %d: %w", msg.Uid, err)
 		return err
 	}
 	r, err := m.NewBodyPartReader(msg.Part)
 	if err != nil {
 		logging.Errorf(
-			"could not get body part reader for message=%d, parts=%#v: %v",
+			"could not get body part reader for message=%d, parts=%#v: %w",
 			msg.Uid, msg.Part, err)
 		return err
 	}
@@ -534,12 +534,12 @@ func (w *Worker) handleFetchFullMessages(msg *types.FetchFullMessages) error {
 	for _, uid := range msg.Uids {
 		m, err := w.c.Message(*w.selected, uid)
 		if err != nil {
-			logging.Errorf("could not get message %d: %v", uid, err)
+			logging.Errorf("could not get message %d: %w", uid, err)
 			return err
 		}
 		r, err := m.NewReader()
 		if err != nil {
-			logging.Errorf("could not get message reader: %v", err)
+			logging.Errorf("could not get message reader: %w", err)
 			return err
 		}
 		defer r.Close()
@@ -570,7 +570,7 @@ func (w *Worker) handleDeleteMessages(msg *types.DeleteMessages) error {
 		}, nil)
 	}
 	if err != nil {
-		logging.Errorf("failed removing messages: %v", err)
+		logging.Errorf("failed removing messages: %w", err)
 		return err
 	}
 	return nil
@@ -580,18 +580,18 @@ func (w *Worker) handleAnsweredMessages(msg *types.AnsweredMessages) error {
 	for _, uid := range msg.Uids {
 		m, err := w.c.Message(*w.selected, uid)
 		if err != nil {
-			logging.Errorf("could not get message: %v", err)
+			logging.Errorf("could not get message: %w", err)
 			w.err(msg, err)
 			continue
 		}
 		if err := m.MarkReplied(msg.Answered); err != nil {
-			logging.Errorf("could not mark message as answered: %v", err)
+			logging.Errorf("could not mark message as answered: %w", err)
 			w.err(msg, err)
 			continue
 		}
 		info, err := m.MessageInfo()
 		if err != nil {
-			logging.Errorf("could not get message info: %v", err)
+			logging.Errorf("could not get message info: %w", err)
 			w.err(msg, err)
 			continue
 		}
@@ -612,19 +612,19 @@ func (w *Worker) handleFlagMessages(msg *types.FlagMessages) error {
 	for _, uid := range msg.Uids {
 		m, err := w.c.Message(*w.selected, uid)
 		if err != nil {
-			logging.Errorf("could not get message: %v", err)
+			logging.Errorf("could not get message: %w", err)
 			w.err(msg, err)
 			continue
 		}
 		flag := flagToMaildir[msg.Flag]
 		if err := m.SetOneFlag(flag, msg.Enable); err != nil {
-			logging.Errorf("could change flag %v to %v on message: %v", flag, msg.Enable, err)
+			logging.Errorf("could change flag %v to %v on message: %w", flag, msg.Enable, err)
 			w.err(msg, err)
 			continue
 		}
 		info, err := m.MessageInfo()
 		if err != nil {
-			logging.Errorf("could not get message info: %v", err)
+			logging.Errorf("could not get message info: %w", err)
 			w.err(msg, err)
 			continue
 		}
@@ -661,12 +661,12 @@ func (w *Worker) handleAppendMessage(msg *types.AppendMessage) error {
 	dest := w.c.Dir(msg.Destination)
 	_, writer, err := dest.Create(translateFlags(msg.Flags))
 	if err != nil {
-		logging.Errorf("could not create message at %s: %v", msg.Destination, err)
+		logging.Errorf("could not create message at %s: %w", msg.Destination, err)
 		return err
 	}
 	defer writer.Close()
 	if _, err := io.Copy(writer, msg.Reader); err != nil {
-		logging.Errorf("could not write message to destination: %v", err)
+		logging.Errorf("could not write message to destination: %w", err)
 		return err
 	}
 	w.worker.PostMessage(&types.Done{
@@ -729,7 +729,7 @@ func (w *Worker) handleCheckMail(msg *types.CheckMail) {
 		w.err(msg, fmt.Errorf("checkmail: timed out"))
 	case err := <-ch:
 		if err != nil {
-			w.err(msg, fmt.Errorf("checkmail: error running command: %v", err))
+			w.err(msg, fmt.Errorf("checkmail: error running command: %w", err))
 		} else {
 			w.done(msg)
 		}

worker/mbox/io.go

@@ -1,6 +1,7 @@
 package mboxer
 
 import (
+	"errors"
 	"io"
 	"io/ioutil"
 	"time"
@@ -16,7 +17,7 @@ func Read(r io.Reader) ([]lib.RawMessage, error) {
 	messages := make([]lib.RawMessage, 0)
 	for {
 		msg, err := mbr.NextMessage()
-		if err == io.EOF {
+		if errors.Is(err, io.EOF) {
 			break
 		} else if err != nil {
 			return nil, err

worker/mbox/models.go

@@ -89,7 +89,7 @@ func (md *mailboxContainer) Copy(dest, src string, uids []uint32) error {
 			}
 			err = destmbox.Append(r, flags)
 			if err != nil {
-				return fmt.Errorf("could not append data to mbox: %v", err)
+				return fmt.Errorf("could not append data to mbox: %w", err)
 			}
 		}
 	}

worker/mbox/worker.go

@@ -2,6 +2,7 @@ package mboxer
 
 import (
 	"bytes"
+	"errors"
 	"fmt"
 	"io/ioutil"
 	"net/url"
@@ -113,12 +114,12 @@ func (w *mboxWorker) handleMessage(msg types.WorkerMessage) error {
 		for _, uid := range w.folder.Uids() {
 			m, err := w.folder.Message(uid)
 			if err != nil {
-				logging.Errorf("could not get message %v", err)
+				logging.Errorf("could not get message %w", err)
 				continue
 			}
 			info, err := lib.MessageInfo(m)
 			if err != nil {
-				logging.Errorf("could not get message info %v", err)
+				logging.Errorf("could not get message info %w", err)
 				continue
 			}
 			infos = append(infos, info)
@@ -176,27 +177,27 @@ func (w *mboxWorker) handleMessage(msg types.WorkerMessage) error {
 	case *types.FetchMessageBodyPart:
 		m, err := w.folder.Message(msg.Uid)
 		if err != nil {
-			logging.Errorf("could not get message %d: %v", msg.Uid, err)
+			logging.Errorf("could not get message %d: %w", msg.Uid, err)
 			reterr = err
 			break
 		}
 
 		contentReader, err := m.NewReader()
 		if err != nil {
-			reterr = fmt.Errorf("could not get message reader: %v", err)
+			reterr = fmt.Errorf("could not get message reader: %w", err)
 			break
 		}
 
 		fullMsg, err := gomessage.Read(contentReader)
 		if err != nil {
-			reterr = fmt.Errorf("could not read message: %v", err)
+			reterr = fmt.Errorf("could not read message: %w", err)
 			break
 		}
 
 		r, err := lib.FetchEntityPartReader(fullMsg, msg.Part)
 		if err != nil {
 			logging.Errorf(
-				"could not get body part reader for message=%d, parts=%#v: %v",
+				"could not get body part reader for message=%d, parts=%#v: %w",
 				msg.Uid, msg.Part, err)
 			reterr = err
 			break
@@ -214,18 +215,18 @@ func (w *mboxWorker) handleMessage(msg types.WorkerMessage) error {
 		for _, uid := range msg.Uids {
 			m, err := w.folder.Message(uid)
 			if err != nil {
-				logging.Errorf("could not get message for uid %d: %v", uid, err)
+				logging.Errorf("could not get message for uid %d: %w", uid, err)
 				continue
 			}
 			r, err := m.NewReader()
 			if err != nil {
-				logging.Errorf("could not get message reader: %v", err)
+				logging.Errorf("could not get message reader: %w", err)
 				continue
 			}
 			defer r.Close()
 			b, err := ioutil.ReadAll(r)
 			if err != nil {
-				logging.Errorf("could not get message reader: %v", err)
+				logging.Errorf("could not get message reader: %w", err)
 				continue
 			}
 			w.worker.PostMessage(&types.FullMessage{
@@ -260,16 +261,16 @@ func (w *mboxWorker) handleMessage(msg types.WorkerMessage) error {
 		for _, uid := range msg.Uids {
 			m, err := w.folder.Message(uid)
 			if err != nil {
-				logging.Errorf("could not get message: %v", err)
+				logging.Errorf("could not get message: %w", err)
 				continue
 			}
 			if err := m.(*message).SetFlag(msg.Flag, msg.Enable); err != nil {
-				logging.Errorf("could change flag %v to %t on message: %v", msg.Flag, msg.Enable, err)
+				logging.Errorf("could change flag %v to %t on message: %w", msg.Flag, msg.Enable, err)
 				continue
 			}
 			info, err := lib.MessageInfo(m)
 			if err != nil {
-				logging.Errorf("could not get message info: %v", err)
+				logging.Errorf("could not get message info: %w", err)
 				continue
 			}
 
@@ -365,7 +366,7 @@ func (w *mboxWorker) handleMessage(msg types.WorkerMessage) error {
 func (w *mboxWorker) Run() {
 	for msg := range w.worker.Actions {
 		msg = w.worker.ProcessAction(msg)
-		if err := w.handleMessage(msg); err == errUnsupported {
+		if err := w.handleMessage(msg); errors.Is(err, errUnsupported) {
 			w.worker.PostMessage(&types.Unsupported{
 				Message: types.RespondTo(msg),
 			}, nil)

worker/notmuch/lib/database.go

@@ -4,6 +4,7 @@
 package lib
 
 import (
+	"errors"
 	"fmt"
 	"time"
 
@@ -55,7 +56,7 @@ func (db *DB) connect(writable bool) error {
 	var err error
 	db.db, err = notmuch.Open(db.path, mode)
 	if err != nil {
-		return fmt.Errorf("could not connect to notmuch db: %v", err)
+		return fmt.Errorf("could not connect to notmuch db: %w", err)
 	}
 	db.lastOpenTime = time.Now()
 	return nil
@@ -112,7 +113,7 @@ func (db *DB) newQuery(ndb *notmuch.DB, query string) (*notmuch.Query, error) {
 	q.SetSortScheme(notmuch.SORT_OLDEST_FIRST)
 	for _, t := range db.excludedTags {
 		err := q.AddTagExclude(t)
-		if err != nil && err != notmuch.ErrIgnored {
+		if errors.Is(err, notmuch.ErrIgnored) {
 			return nil, err
 		}
 	}

worker/notmuch/message.go

@@ -49,7 +49,7 @@ func (m *Message) NewBodyPartReader(requestedParts []int) (io.Reader, error) {
 	defer f.Close()
 	msg, err := message.Read(f)
 	if err != nil {
-		return nil, fmt.Errorf("could not read message: %v", err)
+		return nil, fmt.Errorf("could not read message: %w", err)
 	}
 	return lib.FetchEntityPartReader(msg, requestedParts)
 }

worker/notmuch/worker.go

@@ -7,6 +7,7 @@ import (
 	"bufio"
 	"bytes"
 	"context"
+	"errors"
 	"fmt"
 	"io/ioutil"
 	"net/url"
@@ -61,22 +62,22 @@ func (w *worker) Run() {
 		select {
 		case action := <-w.w.Actions:
 			msg := w.w.ProcessAction(action)
-			if err := w.handleMessage(msg); err == errUnsupported {
+			if err := w.handleMessage(msg); errors.Is(err, errUnsupported) {
 				w.w.PostMessage(&types.Unsupported{
 					Message: types.RespondTo(msg),
 				}, nil)
-				logging.Errorf("ProcessAction(%T) unsupported: %v", msg, err)
+				logging.Errorf("ProcessAction(%T) unsupported: %w", msg, err)
 			} else if err != nil {
 				w.w.PostMessage(&types.Error{
 					Message: types.RespondTo(msg),
 					Error:   err,
 				}, nil)
-				logging.Errorf("ProcessAction(%T) failure: %v", msg, err)
+				logging.Errorf("ProcessAction(%T) failure: %w", msg, err)
 			}
 		case nmEvent := <-w.nmEvents:
 			err := w.handleNotmuchEvent(nmEvent)
 			if err != nil {
-				logging.Errorf("notmuch event failure: %v", err)
+				logging.Errorf("notmuch event failure: %w", err)
 			}
 		}
 	}
@@ -157,22 +158,22 @@ func (w *worker) handleConfigure(msg *types.Configure) error {
 			w.setupErr = nil
 			return
 		}
-		w.setupErr = fmt.Errorf("notmuch: %v", err)
+		w.setupErr = fmt.Errorf("notmuch: %w", err)
 	}()
 
 	u, err := url.Parse(msg.Config.Source)
 	if err != nil {
-		logging.Errorf("error configuring notmuch worker: %v", err)
+		logging.Errorf("error configuring notmuch worker: %w", err)
 		return err
 	}
 	home, err := homedir.Expand(u.Hostname())
 	if err != nil {
-		return fmt.Errorf("could not resolve home directory: %v", err)
+		return fmt.Errorf("could not resolve home directory: %w", err)
 	}
 	pathToDB := filepath.Join(home, u.Path)
 	err = w.loadQueryMap(msg.Config)
 	if err != nil {
-		return fmt.Errorf("could not load query map configuration: %v", err)
+		return fmt.Errorf("could not load query map configuration: %w", err)
 	}
 	excludedTags := w.loadExcludeTags(msg.Config)
 	w.db = notmuch.NewDB(pathToDB, excludedTags)
@@ -313,13 +314,13 @@ func (w *worker) handleFetchMessageHeaders(
 	for _, uid := range msg.Uids {
 		m, err := w.msgFromUid(uid)
 		if err != nil {
-			logging.Errorf("could not get message: %v", err)
+			logging.Errorf("could not get message: %w", err)
 			w.err(msg, err)
 			continue
 		}
 		err = w.emitMessageInfo(m, msg)
 		if err != nil {
-			logging.Errorf("could not emit message info: %v", err)
+			logging.Errorf("could not emit message info: %w", err)
 			w.err(msg, err)
 			continue
 		}
@@ -360,13 +361,13 @@ func (w *worker) handleFetchMessageBodyPart(
 ) error {
 	m, err := w.msgFromUid(msg.Uid)
 	if err != nil {
-		logging.Errorf("could not get message %d: %v", msg.Uid, err)
+		logging.Errorf("could not get message %d: %w", msg.Uid, err)
 		return err
 	}
 	r, err := m.NewBodyPartReader(msg.Part)
 	if err != nil {
 		logging.Errorf(
-			"could not get body part reader for message=%d, parts=%#v: %v",
+			"could not get body part reader for message=%d, parts=%#v: %w",
 			msg.Uid, msg.Part, err)
 		return err
 	}
@@ -386,12 +387,12 @@ func (w *worker) handleFetchFullMessages(msg *types.FetchFullMessages) error {
 	for _, uid := range msg.Uids {
 		m, err := w.msgFromUid(uid)
 		if err != nil {
-			logging.Errorf("could not get message %d: %v", uid, err)
+			logging.Errorf("could not get message %d: %w", uid, err)
 			return err
 		}
 		r, err := m.NewReader()
 		if err != nil {
-			logging.Errorf("could not get message reader: %v", err)
+			logging.Errorf("could not get message reader: %w", err)
 			return err
 		}
 		defer r.Close()
@@ -415,24 +416,24 @@ func (w *worker) handleAnsweredMessages(msg *types.AnsweredMessages) error {
 	for _, uid := range msg.Uids {
 		m, err := w.msgFromUid(uid)
 		if err != nil {
-			logging.Errorf("could not get message: %v", err)
+			logging.Errorf("could not get message: %w", err)
 			w.err(msg, err)
 			continue
 		}
 		if err := m.MarkAnswered(msg.Answered); err != nil {
-			logging.Errorf("could not mark message as answered: %v", err)
+			logging.Errorf("could not mark message as answered: %w", err)
 			w.err(msg, err)
 			continue
 		}
 		err = w.emitMessageInfo(m, msg)
 		if err != nil {
-			logging.Errorf("could not emit message info: %v", err)
+			logging.Errorf("could not emit message info: %w", err)
 			w.err(msg, err)
 			continue
 		}
 	}
 	if err := w.emitDirectoryInfo(w.currentQueryName); err != nil {
-		logging.Errorf("could not emit directory info: %v", err)
+		logging.Errorf("could not emit directory info: %w", err)
 	}
 	w.done(msg)
 	return nil
@@ -442,24 +443,24 @@ func (w *worker) handleFlagMessages(msg *types.FlagMessages) error {
 	for _, uid := range msg.Uids {
 		m, err := w.msgFromUid(uid)
 		if err != nil {
-			logging.Errorf("could not get message: %v", err)
+			logging.Errorf("could not get message: %w", err)
 			w.err(msg, err)
 			continue
 		}
 		if err := m.SetFlag(msg.Flag, msg.Enable); err != nil {
-			logging.Errorf("could not set flag %v as %t for message: %v", msg.Flag, msg.Enable, err)
+			logging.Errorf("could not set flag %v as %t for message: %w", msg.Flag, msg.Enable, err)
 			w.err(msg, err)
 			continue
 		}
 		err = w.emitMessageInfo(m, msg)
 		if err != nil {
-			logging.Errorf("could not emit message info: %v", err)
+			logging.Errorf("could not emit message info: %w", err)
 			w.err(msg, err)
 			continue
 		}
 	}
 	if err := w.emitDirectoryInfo(w.currentQueryName); err != nil {
-		logging.Errorf("could not emit directory info: %v", err)
+		logging.Errorf("could not emit directory info: %w", err)
 	}
 	w.done(msg)
 	return nil
@@ -488,11 +489,11 @@ func (w *worker) handleModifyLabels(msg *types.ModifyLabels) error {
 	for _, uid := range msg.Uids {
 		m, err := w.msgFromUid(uid)
 		if err != nil {
-			return fmt.Errorf("could not get message from uid %d: %v", uid, err)
+			return fmt.Errorf("could not get message from uid %d: %w", uid, err)
 		}
 		err = m.ModifyTags(msg.Add, msg.Remove)
 		if err != nil {
-			return fmt.Errorf("could not modify message tags: %v", err)
+			return fmt.Errorf("could not modify message tags: %w", err)
 		}
 		err = w.emitMessageInfo(m, msg)
 		if err != nil {
@@ -508,7 +509,7 @@ func (w *worker) handleModifyLabels(msg *types.ModifyLabels) error {
 	// and update the list of possible tags
 	w.emitLabelList()
 	if err = w.emitDirectoryInfo(w.currentQueryName); err != nil {
-		logging.Errorf("could not emit directory info: %v", err)
+		logging.Errorf("could not emit directory info: %w", err)
 	}
 	w.done(msg)
 	return nil
@@ -572,11 +573,11 @@ func (w *worker) emitDirectoryContents(parent types.WorkerMessage) error {
 	}
 	uids, err := w.uidsFromQuery(query)
 	if err != nil {
-		return fmt.Errorf("could not fetch uids: %v", err)
+		return fmt.Errorf("could not fetch uids: %w", err)
 	}
 	sortedUids, err := w.sort(uids, w.currentSortCriteria)
 	if err != nil {
-		logging.Errorf("error sorting directory: %v", err)
+		logging.Errorf("error sorting directory: %w", err)
 		return err
 	}
 	w.w.PostMessage(&types.DirectoryContents{
@@ -609,7 +610,7 @@ func (w *worker) emitMessageInfo(m *Message,
 ) error {
 	info, err := m.MessageInfo()
 	if err != nil {
-		return fmt.Errorf("could not get MessageInfo: %v", err)
+		return fmt.Errorf("could not get MessageInfo: %w", err)
 	}
 	w.w.PostMessage(&types.MessageInfo{
 		Message: types.RespondTo(parent),
@@ -621,7 +622,7 @@ func (w *worker) emitMessageInfo(m *Message,
 func (w *worker) emitLabelList() {
 	tags, err := w.db.ListTags()
 	if err != nil {
-		logging.Errorf("could not load tags: %v", err)
+		logging.Errorf("could not load tags: %w", err)
 		return
 	}
 	w.w.PostMessage(&types.LabelList{Labels: tags}, nil)
@@ -637,19 +638,19 @@ func (w *worker) sort(uids []uint32,
 	for _, uid := range uids {
 		m, err := w.msgFromUid(uid)
 		if err != nil {
-			logging.Errorf("could not get message: %v", err)
+			logging.Errorf("could not get message: %w", err)
 			continue
 		}
 		info, err := m.MessageInfo()
 		if err != nil {
-			logging.Errorf("could not get message info: %v", err)
+			logging.Errorf("could not get message info: %w", err)
 			continue
 		}
 		msgInfos = append(msgInfos, info)
 	}
 	sortedUids, err := lib.Sort(msgInfos, criteria)
 	if err != nil {
-		logging.Errorf("could not sort the messages: %v", err)
+		logging.Errorf("could not sort the messages: %w", err)
 		return nil, err
 	}
 	return sortedUids, nil
@@ -673,7 +674,7 @@ func (w *worker) handleCheckMail(msg *types.CheckMail) {
 		w.err(msg, fmt.Errorf("checkmail: timed out"))
 	case err := <-ch:
 		if err != nil {
-			w.err(msg, fmt.Errorf("checkmail: error running command: %v", err))
+			w.err(msg, fmt.Errorf("checkmail: error running command: %w", err))
 		} else {
 			w.done(msg)
 		}

worker/types/thread.go

@@ -42,7 +42,7 @@ func (t *Thread) insertCmp(child *Thread, cmp func(*Thread, *Thread) bool) {
 
 func (t *Thread) Walk(walkFn NewThreadWalkFn) error {
 	err := newWalk(t, walkFn, 0, nil)
-	if err == ErrSkipThread {
+	if errors.Is(err, ErrSkipThread) {
 		return nil
 	}
 	return err
@@ -80,7 +80,7 @@ func newWalk(node *Thread, walkFn NewThreadWalkFn, lvl int, ce error) error {
 	}
 	for child := node.FirstChild; child != nil; child = child.NextSibling {
 		err = newWalk(child, walkFn, lvl+1, err)
-		if err == ErrSkipThread {
+		if errors.Is(err, ErrSkipThread) {
 			err = nil
 			continue
 		} else if err != nil {