api: postImagesCreate(): rename ambiguous err variable

This error is meant to be used in the output stream, and some comments
were added to prevent accidentally using local variables.

Renaming the variable instead to make it less ambiguous.

Signed-off-by: Sebastiaan van Stijn <github@gone.nl>

api/server/router/image/image_routes.go

@@ -29,13 +29,13 @@ func (s *imageRouter) postImagesCreate(ctx context.Context, w http.ResponseWrite
 	}
 
 	var (
-		image    = r.Form.Get("fromImage")
-		repo     = r.Form.Get("repo")
-		tag      = r.Form.Get("tag")
-		message  = r.Form.Get("message")
-		err      error
-		output   = ioutils.NewWriteFlusher(w)
-		platform *specs.Platform
+		image       = r.Form.Get("fromImage")
+		repo        = r.Form.Get("repo")
+		tag         = r.Form.Get("tag")
+		message     = r.Form.Get("message")
+		progressErr error
+		output      = ioutils.NewWriteFlusher(w)
+		platform    *specs.Platform
 	)
 	defer output.Close()
 
@@ -71,23 +71,20 @@ func (s *imageRouter) postImagesCreate(ctx context.Context, w http.ResponseWrite
 				authConfig = &types.AuthConfig{}
 			}
 		}
-		err = s.backend.PullImage(ctx, image, tag, platform, metaHeaders, authConfig, output)
+		progressErr = s.backend.PullImage(ctx, image, tag, platform, metaHeaders, authConfig, output)
 	} else { // import
 		src := r.Form.Get("fromSrc")
-		// 'err' MUST NOT be defined within this block, we need any error
-		// generated from the download to be available to the output
-		// stream processing below
 		os := ""
 		if platform != nil {
 			os = platform.OS
 		}
-		err = s.backend.ImportImage(src, repo, os, tag, message, r.Body, output, r.Form["changes"])
+		progressErr = s.backend.ImportImage(src, repo, os, tag, message, r.Body, output, r.Form["changes"])
 	}
-	if err != nil {
+	if progressErr != nil {
 		if !output.Flushed() {
-			return err
+			return progressErr
 		}
-		_, _ = output.Write(streamformatter.FormatError(err))
+		_, _ = output.Write(streamformatter.FormatError(progressErr))
 	}
 
 	return nil