New: Root folder exists validation for import lists

Also moved the AppendArgument to avoid cases like `Invalid Path: '{path}'`.

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

@@ -19,14 +19,9 @@ namespace NzbDrone.Core.Validation.Paths
 
         protected override bool IsValid(PropertyValidatorContext context)
         {
-            if (context.PropertyValue == null)
-            {
-                return false;
-            }
+            context.MessageFormatter.AppendArgument("path", context.PropertyValue?.ToString());
 
-            context.MessageFormatter.AppendArgument("path", context.PropertyValue.ToString());
-
-            return context.PropertyValue.ToString().IsPathValid(PathValidationType.CurrentOs);
+            return context.PropertyValue != null && context.PropertyValue.ToString().IsPathValid(PathValidationType.CurrentOs);
         }
     }
 }

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

@@ -0,0 +1,25 @@
+using FluentValidation.Validators;
+using NzbDrone.Common.Extensions;
+using NzbDrone.Core.RootFolders;
+
+namespace NzbDrone.Core.Validation.Paths
+{
+    public class RootFolderExistsValidator : PropertyValidator
+    {
+        private readonly IRootFolderService _rootFolderService;
+
+        public RootFolderExistsValidator(IRootFolderService rootFolderService)
+        {
+            _rootFolderService = rootFolderService;
+        }
+
+        protected override string GetDefaultMessageTemplate() => "Root folder '{path}' does not exist";
+
+        protected override bool IsValid(PropertyValidatorContext context)
+        {
+            context.MessageFormatter.AppendArgument("path", context.PropertyValue?.ToString());
+
+            return context.PropertyValue == null || _rootFolderService.All().Exists(r => r.Path.PathEquals(context.PropertyValue.ToString()));
+        }
+    }
+}

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

@@ -17,13 +17,13 @@ namespace NzbDrone.Core.Validation.Paths
 
         protected override bool IsValid(PropertyValidatorContext context)
         {
+            context.MessageFormatter.AppendArgument("path", context.PropertyValue?.ToString());
+
             if (context.PropertyValue == null)
             {
                 return true;
             }
 
-            context.MessageFormatter.AppendArgument("path", context.PropertyValue.ToString());
-
             return !_rootFolderService.All().Exists(r => r.Path.PathEquals(context.PropertyValue.ToString()));
         }
     }

src/Radarr.Api.V3/ImportLists/ImportListController.cs

@@ -12,13 +12,18 @@ namespace Radarr.Api.V3.ImportLists
         public static readonly ImportListResourceMapper ResourceMapper = new ();
         public static readonly ImportListBulkResourceMapper BulkResourceMapper = new ();
 
-        public ImportListController(IImportListFactory importListFactory, QualityProfileExistsValidator qualityProfileExistsValidator)
+        public ImportListController(IImportListFactory importListFactory, RootFolderExistsValidator rootFolderExistsValidator, QualityProfileExistsValidator qualityProfileExistsValidator)
             : base(importListFactory, "importlist", ResourceMapper, BulkResourceMapper)
         {
-            SharedValidator.RuleFor(c => c.RootFolderPath).IsValidPath();
             SharedValidator.RuleFor(c => c.MinimumAvailability).NotNull();
-            SharedValidator.RuleFor(c => c.QualityProfileId).ValidId();
-            SharedValidator.RuleFor(c => c.QualityProfileId).SetValidator(qualityProfileExistsValidator);
+
+            SharedValidator.RuleFor(c => c.RootFolderPath).Cascade(CascadeMode.Stop)
+                .IsValidPath()
+                .SetValidator(rootFolderExistsValidator);
+
+            SharedValidator.RuleFor(c => c.QualityProfileId).Cascade(CascadeMode.Stop)
+                .ValidId()
+                .SetValidator(qualityProfileExistsValidator);
         }
     }
 }