Merge branch 'claudedo/5c80a0aba5d9468a96cf809fc7a6e7a1'

tests/ClaudeDo.Data.Tests/ForeignKeyTests.cs

@@ -69,6 +69,35 @@ public sealed class ForeignKeyTests : IDisposable
         }
     }
 
+    [Fact]
+    public async Task DependsOnTaskId_is_nulled_when_predecessor_deleted_on_fresh_context()
+    {
+        var listId = Guid.NewGuid().ToString();
+        var predecessorId = Guid.NewGuid().ToString();
+        var dependentId = Guid.NewGuid().ToString();
+
+        await using (var ctx = Open())
+        {
+            ctx.Lists.Add(new ListEntity { Id = listId, Name = "L", CreatedAt = DateTime.UtcNow });
+            ctx.Tasks.Add(new TaskEntity { Id = predecessorId, ListId = listId, Title = "Predecessor", Status = TaskStatus.Idle, CreatedAt = DateTime.UtcNow });
+            ctx.Tasks.Add(new TaskEntity { Id = dependentId, ListId = listId, Title = "Dependent", Status = TaskStatus.Idle, DependsOnTaskId = predecessorId, CreatedAt = DateTime.UtcNow });
+            await ctx.SaveChangesAsync();
+        }
+
+        await using (var ctx = Open())
+        {
+            var predecessor = await ctx.Tasks.FindAsync(predecessorId);
+            ctx.Tasks.Remove(predecessor!);
+            await ctx.SaveChangesAsync();
+        }
+
+        await using (var ctx = Open())
+        {
+            var dependent = await ctx.Tasks.AsNoTracking().FirstAsync(t => t.Id == dependentId);
+            Assert.Null(dependent.DependsOnTaskId);
+        }
+    }
+
     // ---- AppSettingsRepository: get-or-create resilience ----
 
     [Fact]