[release/4.0] Improve unique directory generation for temp files (#7528)

* Improve unique directory generation for temp files

Refactor unique directory creation logic to use random file names.

* Update src/Microsoft.ML.Core/Data/Repository.cs

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

* Fix build

---------

Co-authored-by: Eric StJohn <ericstj@microsoft.com>
Co-authored-by: Tarek Mahmoud Sayed <10833894+tarekgh@users.noreply.github.com>
Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

Author: 4 people

src/Microsoft.ML.Core/Data/Repository.cs

@@ -123,10 +123,14 @@ private static string GetShortTempDir(IExceptionContext ectx)
         string tempPath = ectx is IHostEnvironmentInternal iHostInternal ?
             iHostInternal.TempFilePath :
             Path.GetTempPath();
-        int dirNumber = 0;
-        string mlNetTempDir = null!;
-        while (Directory.Exists(mlNetTempDir = Path.Combine(Path.GetFullPath(tempPath), $"ml_dotnet{dirNumber++}"))) ;
-        var path = Path.Combine(mlNetTempDir, Path.GetRandomFileName());
+
+        // Find a unique directory, the directory under Temp and must be unique to this process
+        string path = null;
+        while (path is null || Directory.Exists(path))
+        {
+            path = Path.Combine(Path.GetFullPath(tempPath), $"ml_dotnet_{Path.GetFileNameWithoutExtension(Path.GetRandomFileName())}");
+        }
+
         Directory.CreateDirectory(path);
         return path;
     }