Feature/storage/blob access policy bug

sdk/storage/Azure.Storage.Blobs/CHANGELOG.md

@@ -3,6 +3,7 @@
 ## 12.7.0-preview.1 (Unreleased)
 - Fixed bug where Stream returned from AppendBlobClient.OpenWrite(), BlockBlobClient.OpenWrite() and PageBlobClient.OpenWrite() did not flush while disposing preventing compatibility with using keyword.
 - Fixed bug where Listing Blobs with BlobTraits.Metadata would return BlobItems with null metadata instead of an empty dictionary if no metadata was present.
+- Fixed bug where BlobAccessPolicy.StartsOn and .ExpiresOn would cause the process to crash.
 
 ## 12.6.0 (2020-08-31)
 - Fixed bug where BlobClient.Upload(), BlockBlobClient.Upload(), AppendBlobClient.AppendBlock(), and PageBlobClient.UploadPages() would deadlock if the content stream's position was not 0.

sdk/storage/Azure.Storage.Blobs/src/Models/BlobAccessPolicy.cs

@@ -23,8 +23,8 @@ public System.DateTimeOffset StartsOn
             get
             {
                 return PolicyStartsOn == default ?
-                    StartsOn :
-                    (DateTimeOffset)PolicyStartsOn;
+                    new DateTimeOffset() :
+                    PolicyStartsOn.Value;
             }
             set
             {
@@ -42,8 +42,8 @@ public System.DateTimeOffset ExpiresOn
             get
             {
                 return PolicyExpiresOn == default ?
-                    ExpiresOn :
-                    (DateTimeOffset)PolicyExpiresOn;
+                    new DateTimeOffset() :
+                    PolicyExpiresOn.Value;
             }
             set
             {

sdk/storage/Azure.Storage.Blobs/tests/ContainerClientTests.cs

@@ -1004,6 +1004,18 @@ await test.Container.SetAccessPolicyAsync(
             Assert.AreEqual(signedIdentifiers[0].AccessPolicy.Permissions, acl.AccessPolicy.Permissions);
         }
 
+        [Test]
+        public void BlobAccessPolicyNullStartsOnExpiresOnTest()
+        {
+            BlobAccessPolicy accessPolicy = new BlobAccessPolicy()
+            {
+                Permissions = "rw"
+            };
+
+            Assert.AreEqual(new DateTimeOffset(), accessPolicy.StartsOn);
+            Assert.AreEqual(new DateTimeOffset(), accessPolicy.ExpiresOn);
+        }
+
         [Test]
         public async Task SetAccessPolicyAsync_OldProperties()
         {