Fixed: Allow leading/trailing spaces on non-Windows

(cherry picked from commit 9127a91dfc460f442498a00faed98737047098cd)

Closes #10240

src/NzbDrone.Common.Test/PathExtensionFixture.cs

@@ -379,8 +379,17 @@ namespace NzbDrone.Common.Test
         [TestCase(@" C:\Test\TV\")]
         [TestCase(@" C:\Test\TV")]
 
-        public void IsPathValid_should_be_false(string path)
+        public void IsPathValid_should_be_false_on_windows(string path)
         {
+            WindowsOnly();
+            path.IsPathValid(PathValidationType.CurrentOs).Should().BeFalse();
+        }
+
+        [TestCase(@"")]
+        [TestCase(@"relative/path")]
+        public void IsPathValid_should_be_false_on_unix(string path)
+        {
+            PosixOnly();
             path.AsOsAgnostic().IsPathValid(PathValidationType.CurrentOs).Should().BeFalse();
         }
     }

src/NzbDrone.Common/Extensions/PathExtensions.cs

@@ -153,16 +153,20 @@ namespace NzbDrone.Common.Extensions
                 return false;
             }
 
-            var directoryInfo = new DirectoryInfo(path);
-
-            while (directoryInfo != null)
+            // Only check for leading or trailing spaces for path when running on Windows.
+            if (OsInfo.IsWindows)
             {
-                if (directoryInfo.Name.Trim() != directoryInfo.Name)
+                var directoryInfo = new DirectoryInfo(path);
+
+                while (directoryInfo != null)
                 {
-                    return false;
-                }
+                    if (directoryInfo.Name.Trim() != directoryInfo.Name)
+                    {
+                        return false;
+                    }
 
-                directoryInfo = directoryInfo.Parent;
+                    directoryInfo = directoryInfo.Parent;
+                }
             }
 
             if (validationType == PathValidationType.AnyOs)