Fix storage drivers dropping non EOF errors when listing repositories

This fixes errors other than io.EOF from being dropped when a storage driver
lists repositories. For example, filesystem driver may point to a missing
directory and errors, which then gets subsequently dropped.

Signed-off-by: Edgar Lee <edgar.lee@docker.com>

registry/storage/catalog.go

@@ -25,12 +25,12 @@ func (reg *registry) Repositories(ctx context.Context, repos []string, last stri
 		return 0, errors.New("no space in slice")
 	}
 
-	root, err := pathFor(repositoriesRootPathSpec{})
-	if err != nil {
-		return 0, err
+	root, errVal := pathFor(repositoriesRootPathSpec{})
+	if errVal != nil {
+		return 0, errVal
 	}
 
-	err = Walk(ctx, reg.blobStore.driver, root, func(fileInfo driver.FileInfo) error {
+	errVal = Walk(ctx, reg.blobStore.driver, root, func(fileInfo driver.FileInfo) error {
 		filePath := fileInfo.Path()
 
 		// lop the base path off
@@ -58,7 +58,7 @@ func (reg *registry) Repositories(ctx context.Context, repos []string, last stri
 	n = copy(repos, foundRepos)
 
 	// Signal that we have no more entries by setting EOF
-	if len(foundRepos) <= len(repos) && err != ErrFinishedWalk {
+	if len(foundRepos) <= len(repos) && (errVal == nil || errVal == ErrSkipDir) {
 		errVal = io.EOF
 	}
 

registry/storage/catalog_test.go

@@ -1,6 +1,7 @@
 package storage
 
 import (
+	"fmt"
 	"io"
 	"testing"
 
@@ -123,3 +124,42 @@ func testEq(a, b []string, size int) bool {
 	}
 	return true
 }
+
+func setupBadWalkEnv(t *testing.T) *setupEnv {
+	d := newBadListDriver()
+	ctx := context.Background()
+	registry, err := NewRegistry(ctx, d, BlobDescriptorCacheProvider(memory.NewInMemoryBlobDescriptorCacheProvider()), EnableRedirect)
+	if err != nil {
+		t.Fatalf("error creating registry: %v", err)
+	}
+
+	return &setupEnv{
+		ctx:      ctx,
+		driver:   d,
+		registry: registry,
+	}
+}
+
+type badListDriver struct {
+	driver.StorageDriver
+}
+
+var _ driver.StorageDriver = &badListDriver{}
+
+func newBadListDriver() *badListDriver {
+	return &badListDriver{StorageDriver: inmemory.New()}
+}
+
+func (d *badListDriver) List(ctx context.Context, path string) ([]string, error) {
+	return nil, fmt.Errorf("List error")
+}
+
+func TestCatalogWalkError(t *testing.T) {
+	env := setupBadWalkEnv(t)
+	p := make([]string, 1)
+
+	_, err := env.registry.Repositories(env.ctx, p, "")
+	if err == io.EOF {
+		t.Errorf("Expected catalog driver list error")
+	}
+}