I've found two possible solutions:

• rewrite the QUrl pointing to the iso file with its absolute path (using QFileInfo::canonicalFilePath()); this leads to a problem: once entered the iso file, the panel path is changed to the symlinked path, example : with this symlink cd work && ln -s ~/../software isos I enter in isos/ directory and browse a iso file; when I exit the file, I'm in ~/software and not in ~/work/isos

• port the kio_krarc debugger to kio_iso and rewrite the module to recognize symlinked paths.

I've looked that with katepart krusader uses the first solution, when we open a symlinked file, the canonicalpath is passed to kate; but this not involves panel paths...

Maybe this issue has something to do with that bug:

After entering and exiting an iso file: broken symlinks are not made prominent    
https://bugs.kde.org/show_bug.cgi?id=367707

Anyway if someone is solving one issue perhaps is able to solve the other one, reusing his knowledge.

Using D2603, I was able to find where to problem is:

the path passed to KIso::KIso is wrong (incomplete), it doesn't contains nothing after the symlink.

Configuration test:

~/software where I have all my isos

cd ~/work/ && ln -s ../software iso

I can't browse any iso from /home/davide/work/iso. Trace:

Pid:17267 ┏KIso(109)
Pid:17267      KIso(110): Starting KIso: /home/davide/work/iso - type: 
Pid:17267      ┏prepareDevice(163)
Pid:17267             prepareDevice(164): Preparing: /home/davide/work/iso - type: inode/directory - using the force: 0
Pid:17267      ┗prepareDevice
Pid:17267 ┗KIso

If I create an absolute symlink

cd ~/work/ && ln -s /home/davide/software iso

all work fine. Trace:

Pid:6102 ┏KIso(109)
Pid:6102      KIso(110): Starting KIso: /home/davide/work/isos/gparted-live-0.26.1-5-i686-pae.iso - type: 
Pid:6102      ┏prepareDevice(163)
Pid:6102             prepareDevice(164): Preparing: /home/davide/work/isos/gparted-live-0.26.1-5-i686-pae.iso - type: text/plain - using the force: 0
Pid:6102      ┗prepareDevice
Pid:6102 ┗KIso

Using

cd ~/work/ && ln -s ~/software iso

works to as it produces an absolute symlink.

The problem is not inside KIso, we have to change the way how Krusader passes the symlink paths to KIO.

A fix could be to change in krusader/Panel/panelfunc.cpp:215

from

url.setPath(QDir::cleanPath(url.path()));

to

url.setPath(QDir(url.path()).canonicalPath());

obviously only when url should involve kio_iso; but I don't really like it: you can successfully browse the iso file, but when you exit, you are in the directory targeted by the symlink, not the one where you entered the iso.

Does anyone know how to KIO slavebase works? (to avoid debug/read all kio code)