lfs*,locking,tq: revise ancillary error messages

We rephrase some error message strings which are used when
wrapping other errors so they are clearer and more consistent
with other messages.  Note that these strings will be
prepended to the wrapper errors' messages.

In the lfs/diff_index_scanner.go file in particular we
rephrase the additional message to include a full Git
command ("git diff-index"), which is similar to how errors
are reported in the git package.

lfs/diff_index_scanner.go

@@ -148,7 +148,7 @@ func (s *DiffIndexScanner) Scan() bool {
 
 	s.next, s.err = s.scan(s.from.Text())
 	if s.err != nil {
-		s.err = errors.Wrap(s.err, "scan")
+		s.err = errors.Wrap(s.err, "`git diff-index` scan")
 	}
 
 	return s.err == nil

lfs/gitfilter_smudge.go

@@ -78,7 +78,7 @@ func (f *GitFilter) Smudge(writer io.Writer, ptr *Pointer, workingfile string, d
 		if download {
 			n, err = f.downloadFile(writer, ptr, workingfile, mediafile, manifest, cb)
 		} else {
-			return 0, errors.NewDownloadDeclinedError(statErr, "smudge")
+			return 0, errors.NewDownloadDeclinedError(statErr, "smudge filter")
 		}
 	} else {
 		n, err = f.readLocalFile(writer, ptr, mediafile, workingfile, cb)
@@ -143,14 +143,14 @@ func (f *GitFilter) readLocalFile(writer io.Writer, ptr *Pointer, mediafile stri
 			ext, ok := registeredExts[ptrExt.Name]
 			if !ok {
 				err := errors.New(tr.Tr.Get("extension '%s' is not configured", ptrExt.Name))
-				return 0, errors.Wrap(err, "smudge")
+				return 0, errors.Wrap(err, "smudge filter")
 			}
 			ext.Priority = ptrExt.Priority
 			extensions[ext.Name] = ext
 		}
 		exts, err := config.SortExtensions(extensions)
 		if err != nil {
-			return 0, errors.Wrap(err, "smudge")
+			return 0, errors.Wrap(err, "smudge filter")
 		}
 
 		// pipe extensions in reverse order
@@ -164,7 +164,7 @@ func (f *GitFilter) readLocalFile(writer io.Writer, ptr *Pointer, mediafile stri
 
 		response, err := pipeExtensions(f.cfg, request)
 		if err != nil {
-			return 0, errors.Wrap(err, "smudge")
+			return 0, errors.Wrap(err, "smudge filter")
 		}
 
 		actualExts := make(map[string]*pipeExtResult)
@@ -176,18 +176,18 @@ func (f *GitFilter) readLocalFile(writer io.Writer, ptr *Pointer, mediafile stri
 		oid := response.results[0].oidIn
 		if ptr.Oid != oid {
 			err = errors.New(tr.Tr.Get("actual oid %s during smudge does not match expected %s", oid, ptr.Oid))
-			return 0, errors.Wrap(err, "smudge")
+			return 0, errors.Wrap(err, "smudge filter")
 		}
 
 		for _, expected := range ptr.Extensions {
 			actual := actualExts[expected.Name]
 			if actual.name != expected.Name {
 				err = errors.New(tr.Tr.Get("actual extension name '%s' does not match expected '%s'", actual.name, expected.Name))
-				return 0, errors.Wrap(err, "smudge")
+				return 0, errors.Wrap(err, "smudge filter")
 			}
 			if actual.oidOut != expected.Oid {
 				err = errors.New(tr.Tr.Get("actual oid %s for extension '%s' does not match expected %s", actual.oidOut, expected.Name, expected.Oid))
-				return 0, errors.Wrap(err, "smudge")
+				return 0, errors.Wrap(err, "smudge filter")
 			}
 		}
 

lfsapi/auth.go

@@ -150,7 +150,7 @@ func (c *Client) getCreds(remote string, access creds.Access, req *http.Request)
 
 		credsURL, err := getCredURLForAPI(ef, operation, remote, apiEndpoint, req)
 		if err != nil {
-			return creds.CredentialHelperWrapper{CredentialHelper: creds.NullCreds, Input: nil, Url: nil, Creds: nil}, errors.Wrap(err, "creds")
+			return creds.CredentialHelperWrapper{CredentialHelper: creds.NullCreds, Input: nil, Url: nil, Creds: nil}, errors.Wrap(err, "credentials")
 		}
 
 		if credsURL == nil {
@@ -170,7 +170,7 @@ func (c *Client) getCreds(remote string, access creds.Access, req *http.Request)
 
 	credsURL, err := url.Parse(apiEndpoint.Url)
 	if err != nil {
-		return creds.CredentialHelperWrapper{CredentialHelper: creds.NullCreds, Input: nil, Url: nil, Creds: nil}, errors.Wrap(err, "creds")
+		return creds.CredentialHelperWrapper{CredentialHelper: creds.NullCreds, Input: nil, Url: nil, Creds: nil}, errors.Wrap(err, "credentials")
 	}
 
 	// NTLM uses creds to create the session

locking/locks.go

@@ -73,7 +73,7 @@ func NewClient(remote string, lfsClient *lfsapi.Client, cfg *config.Configuratio
 func (c *Client) SetupFileCache(path string) error {
 	stat, err := os.Stat(path)
 	if err != nil {
-		return errors.Wrap(err, "init lock cache")
+		return errors.Wrap(err, "lock cache initialization")
 	}
 
 	lockFile := path
@@ -83,7 +83,7 @@ func (c *Client) SetupFileCache(path string) error {
 
 	cache, err := NewLockCache(lockFile)
 	if err != nil {
-		return errors.Wrap(err, "init lock cache")
+		return errors.Wrap(err, "lock cache initialization")
 	}
 
 	c.cache = cache
@@ -105,7 +105,7 @@ func (c *Client) LockFile(path string) (Lock, error) {
 		Ref:  &lockRef{Name: c.RemoteRef.Refspec()},
 	})
 	if err != nil {
-		return Lock{}, errors.Wrap(err, "api")
+		return Lock{}, errors.Wrap(err, "locking API")
 	}
 
 	if len(lockRes.Message) > 0 {
@@ -167,7 +167,7 @@ func (c *Client) UnlockFile(path string, force bool) error {
 func (c *Client) UnlockFileById(id string, force bool) error {
 	unlockRes, _, err := c.client.Unlock(c.RemoteRef, c.Remote, id, force)
 	if err != nil {
-		return errors.Wrap(err, "api")
+		return errors.Wrap(err, "locking API")
 	}
 
 	if len(unlockRes.Message) > 0 {

tq/tus_upload.go

@@ -76,7 +76,7 @@ func (a *tusUploadAdapter) DoTransfer(ctx interface{}, t *Transfer, cb ProgressC
 	// Open file for uploading
 	f, err := os.OpenFile(t.Path, os.O_RDONLY, 0644)
 	if err != nil {
-		return errors.Wrap(err, "tus upload")
+		return errors.Wrap(err, "tus.io upload")
 	}
 	defer f.Close()