Case Sensitive Support in Windows

[tc-jschaefer]

Description of the Issue

On Windows 10 (with a build supporting case-sensitive files and WSL, and using file system NTFS), when attempting to save new files (with different case-sensitive names, but otherwise identical when case-folded) to a folder with "setCaseSensitiveInfo" enabled, the user receives an error and cannot save.

Other strange behaviors occur with case-sensitive files, such as being unable to open both files at the same time, within the same instance of N++.

Steps to Reproduce the Issue

1. Click "File"
2. └─ Click "New"
3. Type anything (to enable saving)
4. Click "File"
5. └─ Click "Save"
6.      └─ Select a folder with attribute "setCaseSensitiveInfo" enabled.
7. Type "test.txt"
8. └─ Click "Save"
9. Click "File"
10. └─ Click "New"
11. Type anything (to enable saving)
12. Click "File"
13. └─ Click "Save" (the previous folder with attribute "setCaseSensitiveInfo" enabled will already be the currently selected folder)
14. Type "TEST.TXT"
15. └─ Click "Save"
16. Get error "The file is already opened in Notepad++."

Expected Behavior

The file should save without error.

Actual Behavior

User receives error "The file is already opened in Notepad++.", and cannot proceed.

Debug Information

Notepad++ v8.5.7 (32-bit)
Build time : Sep 6 2023 - 23:07:35
Path : C:\Program Files (x86)\Notepad++\notepad++.exe
Command Line : "C:\Users\jschaefer\Documents\TrialCard\CaseSensitive\TEST.TXT"
Admin mode : OFF
Local Conf mode : OFF
Cloud Config : OFF
OS Name : Windows 10 Enterprise (64-bit)
OS Version : 22H2
OS Build : 19045.2965
Current ANSI codepage : 1252
Plugins :
JSMinNPP (1.2107.2)
mimeTools (2.9)
NppConverter (4.5)
NppExport (0.4)
PoorMansTSqlFormatterNppPlugin (1.6.13.31502)

NOTE

If you don't have WSL already enabled, you'll need to run this in PS and then restart:
• Enable-WindowsOptionalFeature -Online -FeatureName Microsoft-Windows-Subsystem-Linux

Also, to mark a folder as case-sensitive, you can use this command:
• fsutil.exe file setCaseSensitiveInfo enable

[xomx]

when attempting to save new files (with different case-sensitive names, but otherwise identical when case-folded) to a folder with "setCaseSensitiveInfo" enabled, the user receives an error and cannot save.

I have not tried to reproduce/debug this issue but I think I know where the problem is - for some compatibility reason (#11196 (comment)) the N++ does not use the required FILE_FLAG_POSIX_SEMANTICS flag in its saving CreateFile call.

Other strange behaviors occur with case-sensitive files, such as being unable to open both files at the same time

As the N++ currently uses the CRT fopen (which is AFAIK only case insensitive on the Windows platform) for its file-reading, I do not think that this is possible (without replacing with that WIN32 IO CreateFile & FILE_FLAG_POSIX_SEMANTICS way).

[donho]

#14971 has introduced a regression. ref: https://community.notepad-plus-plus.org/topic/25742/notepad-v8-6-6-release-candidate/3?_=1714876196552
It's fixed in:
3609a21

[donho]

In Windows file system, insensitive case of file path is used in the most of environment.
Notepad++ treats the following command
.\notepad++.exe .\config.Xml .\config.xmL as .\notepad++.exe .\config.Xml
and it's the correct treatment for 99% of users.

However there's no way to determinate which situation we are in. (if sensitive case is ON or OFF)
As a result, the case seNsitiVe in Windows will not be supported in Notepad++.