Fix excessive retries missing --max-duration timeout - fixes #4504

This change checks the context whenever rclone might retry, and
doesn't retry if the current context has an error.

This fixes the pathological behaviour of `--max-duration` refusing to
exit because all the context deadline exceeded errors were being
retried.

This unfortunately meant changing the shouldRetry logic in every
backend and doing a lot of context propagation.

See: https://forum.rclone.org/t/add-flag-to-exit-immediately-when-max-duration-reached/22723

backend/googlecloudstorage/googlecloudstorage.go

@@ -329,7 +329,10 @@ func (f *Fs) Features() *fs.Features {
 }
 
 // shouldRetry determines whether a given err rates being retried
-func shouldRetry(err error) (again bool, errOut error) {
+func shouldRetry(ctx context.Context, err error) (again bool, errOut error) {
+	if fserrors.ContextError(ctx, &err) {
+		return false, err
+	}
 	again = false
 	if err != nil {
 		if fserrors.ShouldRetry(err) {
@@ -455,7 +458,7 @@ func NewFs(ctx context.Context, name, root string, m configmap.Mapper) (fs.Fs, e
 		encodedDirectory := f.opt.Enc.FromStandardPath(f.rootDirectory)
 		err = f.pacer.Call(func() (bool, error) {
 			_, err = f.svc.Objects.Get(f.rootBucket, encodedDirectory).Context(ctx).Do()
-			return shouldRetry(err)
+			return shouldRetry(ctx, err)
 		})
 		if err == nil {
 			newRoot := path.Dir(f.root)
@@ -521,7 +524,7 @@ func (f *Fs) list(ctx context.Context, bucket, directory, prefix string, addBuck
 		var objects *storage.Objects
 		err = f.pacer.Call(func() (bool, error) {
 			objects, err = list.Context(ctx).Do()
-			return shouldRetry(err)
+			return shouldRetry(ctx, err)
 		})
 		if err != nil {
 			if gErr, ok := err.(*googleapi.Error); ok {
@@ -624,7 +627,7 @@ func (f *Fs) listBuckets(ctx context.Context) (entries fs.DirEntries, err error)
 		var buckets *storage.Buckets
 		err = f.pacer.Call(func() (bool, error) {
 			buckets, err = listBuckets.Context(ctx).Do()
-			return shouldRetry(err)
+			return shouldRetry(ctx, err)
 		})
 		if err != nil {
 			return nil, err
@@ -750,7 +753,7 @@ func (f *Fs) makeBucket(ctx context.Context, bucket string) (err error) {
 		// service account that only has the "Storage Object Admin" role.  See #2193 for details.
 		err = f.pacer.Call(func() (bool, error) {
 			_, err = f.svc.Objects.List(bucket).MaxResults(1).Context(ctx).Do()
-			return shouldRetry(err)
+			return shouldRetry(ctx, err)
 		})
 		if err == nil {
 			// Bucket already exists
@@ -785,7 +788,7 @@ func (f *Fs) makeBucket(ctx context.Context, bucket string) (err error) {
 				insertBucket.PredefinedAcl(f.opt.BucketACL)
 			}
 			_, err = insertBucket.Context(ctx).Do()
-			return shouldRetry(err)
+			return shouldRetry(ctx, err)
 		})
 	}, nil)
 }
@@ -802,7 +805,7 @@ func (f *Fs) Rmdir(ctx context.Context, dir string) (err error) {
 	return f.cache.Remove(bucket, func() error {
 		return f.pacer.Call(func() (bool, error) {
 			err = f.svc.Buckets.Delete(bucket).Context(ctx).Do()
-			return shouldRetry(err)
+			return shouldRetry(ctx, err)
 		})
 	})
 }
@@ -848,7 +851,7 @@ func (f *Fs) Copy(ctx context.Context, src fs.Object, remote string) (fs.Object,
 	for {
 		err = f.pacer.Call(func() (bool, error) {
 			rewriteResponse, err = rewriteRequest.Context(ctx).Do()
-			return shouldRetry(err)
+			return shouldRetry(ctx, err)
 		})
 		if err != nil {
 			return nil, err
@@ -941,7 +944,7 @@ func (o *Object) readObjectInfo(ctx context.Context) (object *storage.Object, er
 	bucket, bucketPath := o.split()
 	err = o.fs.pacer.Call(func() (bool, error) {
 		object, err = o.fs.svc.Objects.Get(bucket, bucketPath).Context(ctx).Do()
-		return shouldRetry(err)
+		return shouldRetry(ctx, err)
 	})
 	if err != nil {
 		if gErr, ok := err.(*googleapi.Error); ok {
@@ -1012,7 +1015,7 @@ func (o *Object) SetModTime(ctx context.Context, modTime time.Time) (err error)
 			copyObject.DestinationPredefinedAcl(o.fs.opt.ObjectACL)
 		}
 		newObject, err = copyObject.Context(ctx).Do()
-		return shouldRetry(err)
+		return shouldRetry(ctx, err)
 	})
 	if err != nil {
 		return err
@@ -1043,7 +1046,7 @@ func (o *Object) Open(ctx context.Context, options ...fs.OpenOption) (in io.Read
 				_ = res.Body.Close() // ignore error
 			}
 		}
-		return shouldRetry(err)
+		return shouldRetry(ctx, err)
 	})
 	if err != nil {
 		return nil, err
@@ -1109,7 +1112,7 @@ func (o *Object) Update(ctx context.Context, in io.Reader, src fs.ObjectInfo, op
 			insertObject.PredefinedAcl(o.fs.opt.ObjectACL)
 		}
 		newObject, err = insertObject.Context(ctx).Do()
-		return shouldRetry(err)
+		return shouldRetry(ctx, err)
 	})
 	if err != nil {
 		return err
@@ -1124,7 +1127,7 @@ func (o *Object) Remove(ctx context.Context) (err error) {
 	bucket, bucketPath := o.split()
 	err = o.fs.pacer.Call(func() (bool, error) {
 		err = o.fs.svc.Objects.Delete(bucket, bucketPath).Context(ctx).Do()
-		return shouldRetry(err)
+		return shouldRetry(ctx, err)
 	})
 	return err
 }