Merge pull request #2858 from FirelyTeam/bundled-resource-cache-hotfix

Fixed NullReferenceException when enumerating bundled/contained resources
FirelyTeam · Sep 11, 2024 · dea1ba0 · dea1ba0
2 parents 574fea8 + fc3c203
commit dea1ba0
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Showing 2 changed files with 29 additions and 7 deletions.
diff --git a/src/Hl7.Fhir.Base/ElementModel/ReferencedResourceCache.cs b/src/Hl7.Fhir.Base/ElementModel/ReferencedResourceCache.cs
@@ -8,25 +8,37 @@ namespace Hl7.Fhir.ElementModel;
 
 internal class ReferencedResourceCache : IEnumerable<ScopedNode.BundledResource>
 {
- private Dictionary<string, ScopedNode?> _items;
+ private Dictionary<string, ScopedNode> _items;
+ private List<ScopedNode> _unreferenceableItems; // some resources may not have a reference, but are included nonetheless.
 
- public ReferencedResourceCache(IEnumerable<KeyValuePair<string, ScopedNode?>> items)
+ public ReferencedResourceCache(IEnumerable<KeyValuePair<string, ScopedNode>> items)
  {
- _items = new Dictionary<string, ScopedNode?>();
+ _items = new Dictionary<string, ScopedNode>();
+ _unreferenceableItems = [];
  foreach (var item in items)
  {
- _items.Add(item.Key, item.Value);
+ if (item.Key is not null)
+ _items.Add(item.Key, item.Value);
+ else 
+ _unreferenceableItems.Add(item.Value);
+
  }
  }
 
- internal IEnumerable<ScopedNode> Resources => _items.Values.OfType<ScopedNode>();
+ internal IEnumerable<ScopedNode> Resources => _items.Values.Concat(_unreferenceableItems);
 
  internal ScopedNode? ResolveReference(string reference)
  {
  return _items.TryGetValue(reference, out var node) ? node : null;
  }
 
- public IEnumerator<ScopedNode.BundledResource> GetEnumerator() => _items.Select(i => new ScopedNode.BundledResource(i.Key, i.Value)).GetEnumerator();
+ public IEnumerator<ScopedNode.BundledResource> GetEnumerator() => 
+ _items
+ .Select(i => new ScopedNode.BundledResource(i.Key, i.Value))
+ .Concat(
+ _unreferenceableItems.Select(i => new ScopedNode.BundledResource(null, i))
+ )
+ .GetEnumerator();
  IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();
 }
 

diff --git a/src/Hl7.Fhir.ElementModel.Shared.Tests/ScopedNodeTests.cs b/src/Hl7.Fhir.ElementModel.Shared.Tests/ScopedNodeTests.cs
@@ -1,4 +1,5 @@
-using Hl7.Fhir.Model;
+using FluentAssertions;
+using Hl7.Fhir.Model;
 using Hl7.Fhir.Serialization;
 using Hl7.Fhir.Specification;
 using Hl7.Fhir.Specification.Snapshot;
@@ -273,6 +274,15 @@ static bool CCDATypeNameMapper(string typeName, out string canonical)
 
 
  }
+
+ [TestMethod]
+ public void Bundle_WithEntryWithoutFullUrl_ShouldNotThrow()
+ {
+ var bundle = new Bundle() { Type = Bundle.BundleType.Batch, Entry = [new Bundle.EntryComponent() { Resource = new Patient() }]}.ToTypedElement().ToScopedNode();
+
+ var enumerate = () => bundle.BundledResources();
+ enumerate.Should().NotThrow().Subject.Should().ContainSingle(c => c.FullUrl == null);
+ }
 
  private class CCDAResourceResolver : IAsyncResourceResolver
  {