Fix OCI config deserialization issue

Azure · Jun 6, 2024 · 608232b · 608232b
1 parent 8f7ca14
commit 608232b
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Showing 4 changed files with 26 additions and 4 deletions.
diff --git a/src/Bicep.Core/Registry/AzureContainerRegistryManager.cs b/src/Bicep.Core/Registry/AzureContainerRegistryManager.cs
@@ -155,7 +155,9 @@ private static async Task<OciArtifactResult> DownloadManifestAndLayersAsync(IOci
                 .Select(async layer => new OciArtifactLayer(layer.Digest, layer.MediaType, await PullLayerAsync(client, layer)));
             var layers = await Task.WhenAll(layerTasks);
 
-            var config =  new OciArtifactLayer(deserializedManifest.Config.Digest, deserializedManifest.Config.MediaType, await PullLayerAsync(client, deserializedManifest.Config));
+            var config = !deserializedManifest.Config.IsEmpty() ? 
+                new OciArtifactLayer(deserializedManifest.Config.Digest, deserializedManifest.Config.MediaType, await PullLayerAsync(client, deserializedManifest.Config)) :
+                null;
 
             return deserializedManifest.ArtifactType switch
             {

diff --git a/src/Bicep.Core/Registry/Oci/OciDescriptor.cs b/src/Bicep.Core/Registry/Oci/OciDescriptor.cs
@@ -56,5 +56,23 @@ public static string ComputeDigest(string algorithmIdentifier, BinaryData data,
             AlgorithmIdentifierSha512 => SHA512.Create(),
             _ => throw new NotImplementedException($"Unknown hash algorithm '{algorithm}'.")
         };
+
+        public bool IsEmpty()
+        {
+            if (Size == 0)
+            {
+                return true;
+            }
+
+            if (Size == 2 &&
+                OciArtifactReferenceFacts.DigestComparer.Equals(Digest, "sha256:44136fa355b3678a1146ad16f7e8649e94fb4fc21fe77e8310c060f61caaff8a"))
+            {
+                // This SHA is a special case - it refers to "{}" (empty object).
+                // See https://github.com/opencontainers/image-spec/blob/main/manifest.md#guidance-for-an-empty-descriptor for more information.
+                return true;
+            }
+
+            return false;
+        }
     }
 }
diff --git a/src/Bicep.Core/Registry/Oci/OciProviderArtifactResult.cs b/src/Bicep.Core/Registry/Oci/OciProviderArtifactResult.cs
@@ -7,7 +7,7 @@ public class OciProviderArtifactResult : OciArtifactResult
     {
         private readonly OciArtifactLayer mainLayer;
 
-        public OciProviderArtifactResult(BinaryData manifestBits, string manifestDigest, IEnumerable<OciArtifactLayer> layers, OciArtifactLayer config) :
+        public OciProviderArtifactResult(BinaryData manifestBits, string manifestDigest, IEnumerable<OciArtifactLayer> layers, OciArtifactLayer? config) :
             base(manifestBits, manifestDigest, layers)
         {
             var manifest = this.Manifest;
@@ -27,6 +27,6 @@ public OciProviderArtifactResult(BinaryData manifestBits, string manifestDigest,
 
         public override OciArtifactLayer GetMainLayer() => this.mainLayer;
 
-        public OciArtifactLayer Config { get; }
+        public OciArtifactLayer? Config { get; }
     }
 }
diff --git a/src/Bicep.Core/Registry/OciArtifactRegistry.cs b/src/Bicep.Core/Registry/OciArtifactRegistry.cs
@@ -402,7 +402,9 @@ protected override void WriteArtifactContentToCache(OciArtifactReference referen
 
             if (result is OciProviderArtifactResult providerArtifact)
             {
-                var config = JsonSerializer.Deserialize(providerArtifact.Config.Data, OciProvidersV1ConfigSerializationContext.Default.OciProvidersV1Config);
+                var config = providerArtifact.Config is {} ? 
+                    JsonSerializer.Deserialize(providerArtifact.Config.Data, OciProvidersV1ConfigSerializationContext.Default.OciProvidersV1Config) :
+                    null;
 
                 // if the artifact supports local deployment, fetch the provider binary
                 if (config?.LocalDeployEnabled == true)