Fixed: Ensure Root Folder exists when Adding Artist

Closes #5041

src/Lidarr.Api.V1/Artist/ArtistController.cs

@@ -63,6 +63,7 @@ namespace Lidarr.Api.V1.Artist
                             SystemFolderValidator systemFolderValidator,
                             QualityProfileExistsValidator qualityProfileExistsValidator,
                             MetadataProfileExistsValidator metadataProfileExistsValidator,
+                            RootFolderExistsValidator rootFolderExistsValidator,
                             ArtistFolderAsRootFolderValidator artistFolderAsRootFolderValidator)
             : base(signalRBroadcaster)
         {
@@ -95,6 +96,7 @@ namespace Lidarr.Api.V1.Artist
             PostValidator.RuleFor(s => s.Path).IsValidPath().When(s => s.RootFolderPath.IsNullOrWhiteSpace());
             PostValidator.RuleFor(s => s.RootFolderPath)
                          .IsValidPath()
+                         .SetValidator(rootFolderExistsValidator)
                          .SetValidator(artistFolderAsRootFolderValidator)
                          .When(s => s.Path.IsNullOrWhiteSpace());
             PostValidator.RuleFor(s => s.ArtistName).NotEmpty();
@@ -154,6 +156,7 @@ namespace Lidarr.Api.V1.Artist
 
         [RestPostById]
         [Consumes("application/json")]
+        [Produces("application/json")]
         public ActionResult<ArtistResource> AddArtist(ArtistResource artistResource)
         {
             var artist = _addArtistService.AddArtist(artistResource.ToModel());
@@ -163,6 +166,7 @@ namespace Lidarr.Api.V1.Artist
 
         [RestPutById]
         [Consumes("application/json")]
+        [Produces("application/json")]
         public ActionResult<ArtistResource> UpdateArtist(ArtistResource artistResource, bool moveFiles = false)
         {
             var artist = _artistService.GetArtist(artistResource.Id);

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

@@ -1,4 +1,5 @@
 using FluentValidation.Validators;
+using NzbDrone.Common.Disk;
 using NzbDrone.Common.Extensions;
 using NzbDrone.Core.RootFolders;
 
@@ -19,7 +20,7 @@ namespace NzbDrone.Core.Validation.Paths
         {
             context.MessageFormatter.AppendArgument("path", context.PropertyValue?.ToString());
 
-            return context.PropertyValue == null || _rootFolderService.All().Exists(r => r.Path.PathEquals(context.PropertyValue.ToString()));
+            return context.PropertyValue == null || _rootFolderService.All().Exists(r => r.Path.IsPathValid(PathValidationType.CurrentOs) && r.Path.PathEquals(context.PropertyValue.ToString()));
         }
     }
 }