Bug in link creation

[hohwille]

Actual behavior

IDEasy supports FileAccess.link(Path source, Path link, boolean relative) to create a (symbolic) link.
Technically it does Files.createSymbolicLink(link, source) and some special logic to relativise the path if relative is true. The code is a little strange (esp. this adaptPath that might got broken on some refactoring).
However, even in cases where I fixed it, I am getting errors if the relative link path starts with .. giving me a NoSuchFileException. This really seems some kind of bug in the JDK itself that wants to verify that the parent directory of the link to create exists and the parent of .. is ../.. and JDK comes to the conclusion that this does not exist and does not resolve that against the existing file or folder to link.

Reproduce

Not easy to reproduce as a user.

this.context.getFileAccess().link(sourcePath, Path.of("../link"), true);

Expected behavior

I would still love to have some way in Java to do what ln -s sourcePath ../link is doing but due to JDK bug this seems not possible. As a workaround I found a way to make it work with mklink on windows even when using relative paths.
But it also needs to work on Linux and Mac.
As another workaround we might create absolute link in such case.
For the end user it is most important that things work at all...
However, absolute symbolic links may not be as stable and nice...

IDEasy status

IDE_ROOT is set to D:/projects
IDE_HOME is set to D:/projects/project
Your version of IDEasy is 2026.03.001-03_10_09-SNAPSHOT.
You are using a SNAPSHOT version of IDEasy. For stability consider switching to a stable release via 'ide upgrade --mode=stable'
Your version of IDEasy is 2026.03.001-03_10_09-SNAPSHOT but version 2026.03.001-20260311.030907-6 is available. Please run the following command to upgrade to the latest version:
ide upgrade
Your operating system is windows(10.0)@x64 [Windows 11@amd64]
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Found bash executable at: C:/Program Files/Git/usr/bin/bash.***
Found git executable at: C:/Program Files/Git/mingw64/bin/git.***
Your settings are up-to-date.
Successfully completed ide (status)

Related/Dependent issues

#1735 #1500 #1490 etc.

Comments/Hints

I need to implement an urgent fix since this is somehow blocking #1735

[hohwille]

I start to better understand what is going on:
https://docs.oracle.com/en/java/javase/25/docs/api/java.base/java/nio/file/Files.html#createSymbolicLink(java.nio.file.Path,java.nio.file.Path,java.nio.file.attribute.FileAttribute...)

The JavaDoc is extremely confusing:

link - the path of the symbolic link to create
target - the target of the symbolic link

In our code whe have:

source the source {@link Path} to link to, may be relative or absolute.
link the destination {@link Path} where the link shall be created pointing to {@code source}.

So in the JDK link is actually what we call source and what I would consider the symbolic link to create since we want to create a symbolic link at this Path. Further, the we consider source as the target of the symbolic link but JDK JavaDoc means that actual symbolic link to create with this.
So the JDK API is exactly inverted and if someone does not agree that this is causing the perfect confusion then I do not know what else could be worse.
In my changes and cleanup I mixed that accidentally because IMHO the JavaDoc is extremely confusing.

However, there is another catch:
If somehow that fails on windows we create a link using mklink what is most likely what Microsoft is calling a Junction.
And in their implementation they do not support linking to ..\something. Therefore the entire logic to relativise the Paths needs to be implemented completely different for mklink in order to really fix this.
Now I understood the big picture and know how to really fix this messy problem.