Fixed: Prevent setting series folder to drone factory, root folder or another series' folder

src/NzbDrone.Core/Validation/Paths/SeriesPathValidator.cs

@@ -0,0 +1,30 @@
+using FluentValidation.Validators;
+using NzbDrone.Common;
+using NzbDrone.Core.Tv;
+using Omu.ValueInjecter;
+
+namespace NzbDrone.Core.Validation.Paths
+{
+    public class SeriesPathValidator : PropertyValidator
+    {
+        private readonly ISeriesService _seriesService;
+
+        public SeriesPathValidator(ISeriesService seriesService)
+            : base("Path is already configured for another series")
+        {
+            _seriesService = seriesService;
+        }
+
+        protected override bool IsValid(PropertyValidatorContext context)
+        {
+            if (context.PropertyValue == null) return true;
+
+            var series = new Series();
+            series.InjectFrom(context.ParentContext.InstanceToValidate);
+
+            if (series.Id == 0) return true;
+
+            return (!_seriesService.GetAllSeries().Exists(s => s.Path.PathEquals(context.PropertyValue.ToString()) && s.Id != series.Id));
+        }
+    }
+}