Follow up on ignoring FILE_NOT_FOUND on volume enumeration

Directory.Build.props

@@ -26,7 +26,7 @@
   <PropertyGroup>
 
     <!-- DOCSYNC: When changing version number update README.md -->
-    <Version>0.3.8.0</Version>
+    <Version>0.3.9.0</Version>
     <AssemblyVersion>0.9.9999.0</AssemblyVersion>
 
     <Company>Microsoft</Company>

README.md

@@ -43,6 +43,7 @@ File clones on Windows do not actually allocate space on-drive for the clone. Th
 
 [![NuGet version (CopyOnWrite)](https://img.shields.io/nuget/v/CopyOnWrite?style=plastic)](https://www.nuget.org/packages/CopyOnWrite)
 
+* 0.3.9 September 2024: Fix https://github.com/microsoft/CopyOnWrite/issues/44 - follow up on ignoring FILE_NOT_FOUND on volume enumeration
 * 0.3.8 March 2024: Fix https://github.com/microsoft/MSBuildSdks/issues/546 - ignore FILE_NOT_FOUND on volume enumeration. Plus add SourceLink to the main library.
 * 0.3.7 September 2023: Fix #30 - ignore ACCESS_DENIED on volume enumeration to avoid need to escalate privilege on Windows.
 * 0.3.6 July 2023: Set AssemblyVersion to 0.9.9999.0 to allow mixing different minor-version binaries from different packages in the same appdomain/process.

lib/Windows/VolumeEnumerator.cs

@@ -117,7 +117,13 @@ public IEnumerable<VolumePaths> GetVolumesAndVolumePaths()
 
         while (GetNextVolume(out string? volumeName))
         {
-            yield return new VolumePaths(volumeName!, GetVolumePathNamesForVolumeName(volumeName!, driveLetterUpperToSubstDriveLetterUpper));
+            IReadOnlyList<string> volumePathNames = GetVolumePathNamesForVolumeName(volumeName!, driveLetterUpperToSubstDriveLetterUpper);
+            if (volumePathNames.Count == 0)
+            {
+                // Skip volumes with no mount points.
+                continue;
+            }
+            yield return new VolumePaths(volumeName!, volumePathNames);
         }
     }
 
@@ -137,6 +143,12 @@ private static IReadOnlyList<string> GetVolumePathNamesForVolumeName(
             if (!success)
             {
                 int lastErr = Marshal.GetLastWin32Error();
+                if (lastErr == NativeMethods.ERROR_FILE_NOT_FOUND)
+                {
+                    // No mount points for this volume.
+                    return Array.Empty<string>();
+                }
+
                 if (lastErr != NativeMethods.ERROR_MORE_DATA)
                 {
                     throw new Win32Exception(lastErr,

lib/Windows/VolumeInfoCache.cs

@@ -103,8 +103,6 @@ public VolumeInfo GetVolumeForPath(string path)
                                     "If the drive was added recently you may need to recreate the filesystem cache.");
     }
 
-    private const int ERROR_FILE_NOT_FOUND = 2;
-    private const int ERROR_ACCESS_DENIED = 5;
     private const int ERROR_NOT_READY = 21;
     private const int ERROR_INVALID_PARAMETER = 87;
     private const int ERROR_UNRECOGNIZED_VOLUME = 1005;
@@ -135,8 +133,8 @@ public VolumeInfo GetVolumeForPath(string path)
                 lastErr == ERROR_NOT_READY ||
                 lastErr == ERROR_INVALID_PARAMETER ||
                 lastErr == FVE_E_LOCKED_VOLUME ||
-                lastErr == ERROR_ACCESS_DENIED ||
-                lastErr == ERROR_FILE_NOT_FOUND)
+                lastErr == NativeMethods.ERROR_ACCESS_DENIED ||
+                lastErr == NativeMethods.ERROR_FILE_NOT_FOUND)
             {
                 return null;
             }