java-topology/defects/efcore/patch/efcore-0002-add-principals-hashset.patch

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# UNDF: UNDF-2026-000000058
diff --git a/src/EFCore/Metadata/IReadOnlyProperty.cs b/src/EFCore/Metadata/IReadOnlyProperty.cs
index xxxxxxx..xxxxxxx 100644
--- a/src/EFCore/Metadata/IReadOnlyProperty.cs
+++ b/src/EFCore/Metadata/IReadOnlyProperty.cs
@@ -229,19 +229,27 @@ namespace Microsoft.EntityFrameworkCore.Metadata;
IReadOnlyList<T> GetPrincipals<T>()
where T : IReadOnlyProperty
{
var principals = new List<T> { (T)this };
- AddPrincipals((T)this, principals);
+ var visited = new HashSet<T>(ReferenceEqualityComparer.Instance) { (T)this };
+ AddPrincipals((T)this, principals, visited);
return principals;
}
- private static void AddPrincipals<T>(T property, List<T> visited)
+ // efcore-0002 fix: pass a HashSet<T> for O(1) duplicate detection.
+ // Previously List<T>: visited.Contains() is O(N) per call, invoked inside
+ // a recursive traversal over foreignKey.Properties × FK chains, giving
+ // O(P²) cost where P = principal chain length. HashSet reduces to O(P).
+ private static void AddPrincipals<T>(T property, List<T> principals, HashSet<T> visited)
where T : IReadOnlyProperty
{
foreach (var foreignKey in property.GetContainingForeignKeys())
{
for (var propertyIndex = 0; propertyIndex < foreignKey.Properties.Count; propertyIndex++)
{
if (ReferenceEquals(property, foreignKey.Properties[propertyIndex]))
{
var principal = (T)foreignKey.PrincipalKey.Properties[propertyIndex];
- if (!visited.Contains(principal))
+ if (visited.Add(principal))
{
- visited.Add(principal);
-
- AddPrincipals(principal, visited);
+ principals.Add(principal);
+ AddPrincipals(principal, principals, visited);
}
}
}
}
}