Remove github.com/pkg/errors and replace with std library version

This is possible now that we no longer support go1.12 and brings
rclone into line with standard practices in the Go world.

This also removes errors.New and errors.Errorf from lib/errors and
prefers the stdlib errors package over lib/errors.

lib/rest/rest.go

@@ -8,6 +8,8 @@ import (
 	"context"
 	"encoding/json"
 	"encoding/xml"
+	"errors"
+	"fmt"
 	"io"
 	"io/ioutil"
 	"mime/multipart"
@@ -15,7 +17,6 @@ import (
 	"net/url"
 	"sync"
 
-	"github.com/pkg/errors"
 	"github.com/rclone/rclone/fs"
 	"github.com/rclone/rclone/lib/readers"
 )
@@ -51,9 +52,9 @@ func ReadBody(resp *http.Response) (result []byte, err error) {
 func defaultErrorHandler(resp *http.Response) (err error) {
 	body, err := ReadBody(resp)
 	if err != nil {
-		return errors.Wrap(err, "error reading error out of body")
+		return fmt.Errorf("error reading error out of body: %w", err)
 	}
-	return errors.Errorf("HTTP error %v (%v) returned body: %q", resp.StatusCode, resp.Status, body)
+	return fmt.Errorf("HTTP error %v (%v) returned body: %q", resp.StatusCode, resp.Status, body)
 }
 
 // SetErrorHandler sets the handler to decode an error response when
@@ -272,7 +273,7 @@ func (api *Client) Call(ctx context.Context, opts *Opts) (resp *http.Response, e
 		err = api.signer(req)
 		api.mu.RLock()
 		if err != nil {
-			return nil, errors.Wrap(err, "signer failed")
+			return nil, fmt.Errorf("signer failed: %w", err)
 		}
 	}
 	api.mu.RUnlock()
@@ -286,7 +287,7 @@ func (api *Client) Call(ctx context.Context, opts *Opts) (resp *http.Response, e
 			err = api.errorHandler(resp)
 			if err.Error() == "" {
 				// replace empty errors with something
-				err = errors.Errorf("http error %d: %v", resp.StatusCode, resp.Status)
+				err = fmt.Errorf("http error %d: %v", resp.StatusCode, resp.Status)
 			}
 			return resp, err
 		}
@@ -364,7 +365,7 @@ func MultipartUpload(ctx context.Context, in io.Reader, params url.Values, conte
 			for _, val := range vals {
 				err = writer.WriteField(key, val)
 				if err != nil {
-					_ = bodyWriter.CloseWithError(errors.Wrap(err, "create metadata part"))
+					_ = bodyWriter.CloseWithError(fmt.Errorf("create metadata part: %w", err))
 					return
 				}
 			}
@@ -373,20 +374,20 @@ func MultipartUpload(ctx context.Context, in io.Reader, params url.Values, conte
 		if in != nil {
 			part, err := writer.CreateFormFile(contentName, fileName)
 			if err != nil {
-				_ = bodyWriter.CloseWithError(errors.Wrap(err, "failed to create form file"))
+				_ = bodyWriter.CloseWithError(fmt.Errorf("failed to create form file: %w", err))
 				return
 			}
 
 			_, err = io.Copy(part, in)
 			if err != nil {
-				_ = bodyWriter.CloseWithError(errors.Wrap(err, "failed to copy data"))
+				_ = bodyWriter.CloseWithError(fmt.Errorf("failed to copy data: %w", err))
 				return
 			}
 		}
 
 		err = writer.Close()
 		if err != nil {
-			_ = bodyWriter.CloseWithError(errors.Wrap(err, "failed to close form"))
+			_ = bodyWriter.CloseWithError(fmt.Errorf("failed to close form: %w", err))
 			return
 		}
 

lib/rest/url.go

@@ -1,9 +1,8 @@
 package rest
 
 import (
+	"fmt"
 	"net/url"
-
-	"github.com/pkg/errors"
 )
 
 // URLJoin joins a URL and a path returning a new URL
@@ -12,7 +11,7 @@ import (
 func URLJoin(base *url.URL, path string) (*url.URL, error) {
 	rel, err := url.Parse(path)
 	if err != nil {
-		return nil, errors.Wrapf(err, "Error parsing %q as URL", path)
+		return nil, fmt.Errorf("Error parsing %q as URL: %w", path, err)
 	}
 	return base.ResolveReference(rel), nil
 }