jgit considers the file path src/Con.java invalid on Windows

[Luro02]

Version

7.1.0.202411261347-r

Operating System

Windows

Bug description

On Windows certain filenames are forbidden like CON.
jgit validates the file paths and throws an exception if it is not valid.

In my case the filepath is src/Con.java, where Con.java is a file and src is a folder.

The validation code does not seem to consider the file extension.

The filename Con.java is a valid file on windows:

CON (without any extension) is considered invalid:

Actual behavior

org.eclipse.jgit.dircache.InvalidPathException: Invalid path: src/Con.java
	at org.eclipse.jgit.dircache.DirCacheCheckout.checkValidPathSegment(DirCacheCheckout.java:1609)
	at org.eclipse.jgit.dircache.DirCacheCheckout.checkValidPath(DirCacheCheckout.java:1598)
	at org.eclipse.jgit.dircache.DirCacheCheckout.processEntry(DirCacheCheckout.java:387)
	at org.eclipse.jgit.dircache.DirCacheCheckout.prescanOneTree(DirCacheCheckout.java:354)
	at org.eclipse.jgit.dircache.DirCacheCheckout.doCheckout(DirCacheCheckout.java:512)
	at org.eclipse.jgit.dircache.DirCacheCheckout.checkout(DirCacheCheckout.java:480)
        ...
Caused by: org.eclipse.jgit.errors.CorruptObjectException: invalid name 'CON'
	at org.eclipse.jgit.lib.ObjectChecker.report(ObjectChecker.java:781)
	at org.eclipse.jgit.lib.ObjectChecker.checkNotWindowsDevice(ObjectChecker.java:1029)
	at org.eclipse.jgit.lib.ObjectChecker.checkPathSegment2(ObjectChecker.java:903)
	at org.eclipse.jgit.lib.ObjectChecker.checkPathSegment(ObjectChecker.java:849)
	at org.eclipse.jgit.dircache.DirCacheCheckout.checkValidPathSegment(DirCacheCheckout.java:1606)
	... 45 more

Expected behavior

No crash

Relevant log output

No response

Other information

No response

[tomaswolf]

Interesting. According to the commit message of the commit that introduced this check this is intentional. Beats me why, though.

[Luro02]

Interesting. According to the commit message of the commit that introduced this check this is intentional. Beats me why, though.

Not sure why one would want to prevent cloning of these files, they are perfectly valid.

An option to disable these checks would have been nice... Overriding the SystemReader to return false for windows is technically an option, but it does not work because then the code will try to set posix properties on the file...

[msohn]

Microsoft recommends to not use such names, see https://learn.microsoft.com/en-us/windows/win32/fileio/naming-a-file which says

Do not use the following reserved names for the name of a file:

CON, PRN, AUX, NUL, COM0, COM1, COM2, COM3, COM4, COM5, COM6, COM7, COM8, COM9, COM¹, COM², COM³, LPT0, LPT1, LPT2, LPT3, LPT4, LPT5, LPT6, LPT7, LPT8, LPT9, LPT¹, LPT², and LPT³. Also avoid these names followed immediately by an extension; for example, NUL.txt and NUL.tar.gz are both equivalent to NUL. For more information, see Namespaces.