cache: add fallback for snapshotID

In older BuildKit versions snapshotID was not always set if record was not created with GetByBlob method. Old code defaulted to cache record ID in that case but that broke with the metadata interface refactor. Signed-off-by: Tonis Tiigi <[email protected]> (cherry picked from commit 2c0c429)
moby · Feb 13, 2023 · b924f0b · b924f0b
1 parent 95aaabd
commit b924f0b
Showing 1 changed file with 7 additions and 1 deletion.
diff --git a/cache/metadata.go b/cache/metadata.go
@@ -251,7 +251,13 @@ func (md *cacheMetadata) queueMediaType(str string) error {
 }
 
 func (md *cacheMetadata) getSnapshotID() string {
-	return md.GetString(keySnapshot)
+	sid := md.GetString(keySnapshot)
+	// Note that historic buildkit releases did not always set the snapshot ID.
+	// Fallback to record ID is needed for old build cache compatibility.
+	if sid == "" {
+		return md.ID()
+	}
+	return sid
 }
 
 func (md *cacheMetadata) queueSnapshotID(str string) error {