Always store metadata.digest in cache even if image doesn't exists

go.work.sum

@@ -127,6 +127,7 @@ cloud.google.com/go/webrisk v1.7.0/go.mod h1:mVMHgEYH0r337nmt1JyLthzMr6YxwN1aAIE
 cloud.google.com/go/websecurityscanner v1.4.0/go.mod h1:ebit/Fp0a+FWu5j4JOmJEV8S8CzdTkAS77oDsiSqYWQ=
 cloud.google.com/go/workflows v1.9.0/go.mod h1:ZGkj1aFIOd9c8Gerkjjq7OW7I5+l6cSvT3ujaO/WwSA=
 github.com/NYTimes/gziphandler v1.1.1/go.mod h1:n/CVRwUEOgIxrgPvAQhUUr9oeUtvrhMomdKFjzJNB0c=
+github.com/apex/log v1.1.4 h1:3Zk+boorIQAAGBrHn0JUtAau4ihMamT4WdnfdnXM1zQ=
 github.com/cespare/xxhash v1.1.0 h1:a6HrQnmkObjyL+Gs60czilIUGqrzKutQD6XZog3p+ko=
 github.com/chzyer/logex v1.2.0/go.mod h1:9+9sk7u7pGNWYMkh0hdiL++6OeibzJccyQU4p4MedaY=
 github.com/chzyer/readline v1.5.0/go.mod h1:x22KAscuvRqlLoK9CsoYsmxoXZMMFVyOl86cAH8qUic=
@@ -146,7 +147,6 @@ github.com/ianlancetaylor/demangle v0.0.0-20220319035150-800ac71e25c2/go.mod h1:
 github.com/imdario/mergo v0.3.6/go.mod h1:2EnlNZ0deacrJVfApfmtdGgDfMuh/nq6Ok1EcJh5FfA=
 github.com/onsi/ginkgo/v2 v2.1.4/go.mod h1:um6tUpWM/cxCK3/FK8BXqEiUMUwRgSM4JXG47RKZmLU=
 github.com/onsi/ginkgo/v2 v2.9.1/go.mod h1:FEcmzVcCHl+4o9bQZVab+4dC9+j+91t2FHSzmGAPfuo=
-github.com/onsi/gomega v1.27.6/go.mod h1:PIQNjfQwkP3aQAH7lf7j87O/5FiNr+ZR8+ipb+qQlhg=
 github.com/rogpeppe/go-internal v1.10.0/go.mod h1:UQnix2H7Ngw/k4C5ijL5+65zddjncjaFoBhdsK/akog=
 github.com/russross/blackfriday v1.6.0 h1:KqfZb0pUVN2lYqZUYRddxF4OR8ZMURnJIG5Y3VRLtww=
 github.com/yuin/goldmark v1.4.13/go.mod h1:6yULJ656Px+3vBD8DxQVa3kxgyrAnzto9xy5taEt/CY=
@@ -191,8 +191,5 @@ google.golang.org/grpc v1.51.0/go.mod h1:wgNDFcnuBGmxLKI/qn4T+m5BtEBYXJPvibbUPsA
 k8s.io/api v0.27.1/go.mod h1:z5g/BpAiD+f6AArpqNjkY+cji8ueZDU/WV1jcj5Jk4E=
 k8s.io/gengo v0.0.0-20220913193501-391367153a38/go.mod h1:FiNAH4ZV3gBg2Kwh89tzAEV2be7d5xI0vBa/VySYy3E=
 k8s.io/klog v1.0.0 h1:Pt+yjF5aB1xDSVbau4VsWe+dQNzA0qv1LlXdC2dF6Q8=
-k8s.io/klog/v2 v2.90.1/go.mod h1:y1WjHnz7Dj687irZUWR/WLkLc5N1YHtjLdmgWjndZn0=
 k8s.io/kube-openapi v0.0.0-20230308215209-15aac26d736a h1:gmovKNur38vgoWfGtP5QOGNOA7ki4n6qNYoFAgMlNvg=
 k8s.io/kube-openapi v0.0.0-20230308215209-15aac26d736a/go.mod h1:y5VtZWM9sHHc2ZodIH/6SHzXj+TPU5USoA8lcIeKEKY=
-k8s.io/utils v0.0.0-20230209194617-a36077c30491/go.mod h1:OLgZIPagt7ERELqWJFomSt595RzquPNLL48iOWgYOg0=
-sigs.k8s.io/json v0.0.0-20221116044647-bc3834ca7abd/go.mod h1:B8JuhiUyNFVKdsE8h686QcCxMaH6HrOAZj4vswFpcB0=

pkg/discovery/oci_dbbacked.go

@@ -246,13 +246,16 @@ func (od *DBBackedOCIDiscovery) checkImageCache() (string, string) {
 	}
 
 	correctHashFileForInventoryImage := od.checkDigestFileExistance(hashHexValInventoryImage, "")
-	correctHashFileForMetadataImage := ""
 
 	pluginInventoryMetadataImage, _ := airgapped.GetPluginInventoryMetadataImage(od.image)
-	_, hashHexValMetadataImage, err := carvelhelpers.GetImageDigest(pluginInventoryMetadataImage)
-	if err == nil {
-		correctHashFileForMetadataImage = od.checkDigestFileExistance(hashHexValMetadataImage, "metadata.")
-	}
+	_, hashHexValMetadataImage, _ := carvelhelpers.GetImageDigest(pluginInventoryMetadataImage)
+	// Always store the metadata image digest file even if the image does not exists
+	// If image does not exists a file named `metadata.digest.` will be stored
+	// If image exists a file names `metadata.digest.<hexval>` will be stored
+	// It is important to store the metadata digest file irrespective of image exists
+	// or not for future comparisons and validating the cache
+	correctHashFileForMetadataImage := od.checkDigestFileExistance(hashHexValMetadataImage, "metadata.")
+
 	return correctHashFileForInventoryImage, correctHashFileForMetadataImage
 }