From be1235458d6e1760e0388abdadeb9ea1ce9a2817 Mon Sep 17 00:00:00 2001
From: Malte Poll <1780588+malt3@users.noreply.github.com>
Date: Tue, 2 Dec 2025 14:48:07 +0100
Subject: [PATCH] pkg/registry: export ErrNotFound

Custom BlobHandler implementations need access to this error. Otherwise it's impossible for them to signal missing blobs.
---
 pkg/registry/blobs.go      | 20 ++++++++++----------
 pkg/registry/blobs_disk.go |  5 ++++-
 2 files changed, 14 insertions(+), 11 deletions(-)

diff --git a/pkg/registry/blobs.go b/pkg/registry/blobs.go
index c83e54799..015a7b310 100644
--- a/pkg/registry/blobs.go
+++ b/pkg/registry/blobs.go
@@ -103,8 +103,8 @@ func (r *bytesCloser) Close() error {
 
 func (e redirectError) Error() string { return fmt.Sprintf("redirecting (%d): %s", e.Code, e.Location) }
 
-// errNotFound represents an error locating the blob.
-var errNotFound = errors.New("not found")
+// ErrNotFound represents an error locating the blob.
+var ErrNotFound = errors.New("not found")
 
 type memHandler struct {
 	m    map[string][]byte
@@ -119,7 +119,7 @@ func (m *memHandler) Stat(_ context.Context, _ string, h v1.Hash) (int64, error)
 
 	b, found := m.m[h.String()]
 	if !found {
-		return 0, errNotFound
+		return 0, ErrNotFound
 	}
 	return int64(len(b)), nil
 }
@@ -130,7 +130,7 @@ func (m *memHandler) Get(_ context.Context, _ string, h v1.Hash) (io.ReadCloser,
 
 	b, found := m.m[h.String()]
 	if !found {
-		return nil, errNotFound
+		return nil, ErrNotFound
 	}
 	return &bytesCloser{bytes.NewReader(b)}, nil
 }
@@ -153,7 +153,7 @@ func (m *memHandler) Delete(_ context.Context, _ string, h v1.Hash) error {
 	defer m.lock.Unlock()
 
 	if _, found := m.m[h.String()]; !found {
-		return errNotFound
+		return ErrNotFound
 	}
 
 	delete(m.m, h.String())
@@ -206,7 +206,7 @@ func (b *blobs) handle(resp http.ResponseWriter, req *http.Request) *regError {
 		var size int64
 		if bsh, ok := b.blobHandler.(BlobStatHandler); ok {
 			size, err = bsh.Stat(req.Context(), repo, h)
-			if errors.Is(err, errNotFound) {
+			if errors.Is(err, ErrNotFound) {
 				return regErrBlobUnknown
 			} else if err != nil {
 				var rerr redirectError
@@ -218,7 +218,7 @@ func (b *blobs) handle(resp http.ResponseWriter, req *http.Request) *regError {
 			}
 		} else {
 			rc, err := b.blobHandler.Get(req.Context(), repo, h)
-			if errors.Is(err, errNotFound) {
+			if errors.Is(err, ErrNotFound) {
 				return regErrBlobUnknown
 			} else if err != nil {
 				var rerr redirectError
@@ -254,7 +254,7 @@ func (b *blobs) handle(resp http.ResponseWriter, req *http.Request) *regError {
 		var r io.Reader
 		if bsh, ok := b.blobHandler.(BlobStatHandler); ok {
 			size, err = bsh.Stat(req.Context(), repo, h)
-			if errors.Is(err, errNotFound) {
+			if errors.Is(err, ErrNotFound) {
 				return regErrBlobUnknown
 			} else if err != nil {
 				var rerr redirectError
@@ -266,7 +266,7 @@ func (b *blobs) handle(resp http.ResponseWriter, req *http.Request) *regError {
 			}
 
 			rc, err := b.blobHandler.Get(req.Context(), repo, h)
-			if errors.Is(err, errNotFound) {
+			if errors.Is(err, ErrNotFound) {
 				return regErrBlobUnknown
 			} else if err != nil {
 				var rerr redirectError
@@ -283,7 +283,7 @@ func (b *blobs) handle(resp http.ResponseWriter, req *http.Request) *regError {
 
 		} else {
 			tmp, err := b.blobHandler.Get(req.Context(), repo, h)
-			if errors.Is(err, errNotFound) {
+			if errors.Is(err, ErrNotFound) {
 				return regErrBlobUnknown
 			} else if err != nil {
 				var rerr redirectError
diff --git a/pkg/registry/blobs_disk.go b/pkg/registry/blobs_disk.go
index 361390f04..b624d22f6 100644
--- a/pkg/registry/blobs_disk.go
+++ b/pkg/registry/blobs_disk.go
@@ -37,15 +37,17 @@ func (m *diskHandler) blobHashPath(h v1.Hash) string {
 func (m *diskHandler) Stat(_ context.Context, _ string, h v1.Hash) (int64, error) {
 	fi, err := os.Stat(m.blobHashPath(h))
 	if errors.Is(err, os.ErrNotExist) {
-		return 0, errNotFound
+		return 0, ErrNotFound
 	} else if err != nil {
 		return 0, err
 	}
 	return fi.Size(), nil
 }
+
 func (m *diskHandler) Get(_ context.Context, _ string, h v1.Hash) (io.ReadCloser, error) {
 	return os.Open(m.blobHashPath(h))
 }
+
 func (m *diskHandler) Put(_ context.Context, _ string, h v1.Hash, rc io.ReadCloser) error {
 	// Put the temp file in the same directory to avoid cross-device problems
 	// during the os.Rename.  The filenames cannot conflict.
@@ -66,6 +68,7 @@ func (m *diskHandler) Put(_ context.Context, _ string, h v1.Hash, rc io.ReadClos
 	}
 	return os.Rename(f.Name(), m.blobHashPath(h))
 }
+
 func (m *diskHandler) Delete(_ context.Context, _ string, h v1.Hash) error {
 	return os.Remove(m.blobHashPath(h))
 }