Perforce versioning of external packages fails when the workspace root has a lowercase drive letter

How to reproduce:

1. Download and extract the attached “IN-152273” folder to the root of the C drive (C:\IN-152273)
2. In the extracted “IN-152273” folder, right-click anywhere and select “Open in Terminal”
3. Run the “Set-ExecutionPolicy -Scope Process -ExecutionPolicy Bypass -Force” command
4. Enter “.\Setup-P4Repro.ps1” and press Enter to run the PS script
5. Once the setup has finished, verify that the server is running by copy-pasting the code snippet at the bottom of the description
6. Confirm that the packages reached the depot by running the “& $p4 @c have //depot/IN-152273/_ExternalPackages/...” command (it should print a list of depot paths ending with #1)
7. Open the “VCSExternalPackageRepro” project in the Unity Editor (C:\IN-152273\VCSExternalPackageRepro) and wait for the import to finish
8. Confirm that the external packages were installed by looking for “Repro Counter” and “Repro Label” in the Package Manager’s “In Project” tab (Window → Package Manager)
9. Open “Edit → Project Settings” and navigate to the “Version Control” tab
10. Enter the settings listed in the “notes” section
11. Ensure the “Version Packages Outside Project” checkbox is enabled
12. Select “Connect” and close the Project Settings window
13. In the Project window, right-click the “Counter.cs” script (Packages → Repo Counter → Runtime)
14. Verify that “Version Control → Check Out” is not greyed out (workspace root has an uppercase drive letter - no repro)
15. Repeat step 2
16. Change the workspace root to a lowercase drive letter by running the “.\Set-WorkspaceRootCase.ps1 -Case lower” command
17. Reopen the “VCSExternalPackageRepro” project in the Unity Editor
18. Repeat step 13
19. Observe the “Version Control → Check Out” option

Actual result: the “Check Out” option is greyed out
Expected result: the “Check Out” option is selectable (same as step 14)

Reproducible with: 6000.0.0f1, 6000.0.83f1, 6000.3.23f1, 6000.6.0f1, 6000.7.0a6

Reproducible on: Windows 11
Not reproducible on: macOS 15.7.9, M1 max (by reporter)

Notes:

• To verify that the Perforce server is running, enter:

$p4 = 'C:\P4Test\bin\p4.exe'
$c  = @('-p','localhost:16273','-u','testuser','-c','IN-152273-ws')
& $p4 @c info

• Settings for the “Version Control” tab in the Project Settings:

Mode : Perforce
Username : testuser
Workspace : IN-152273-ws
Server : localhost:16273