About “lexists”, I meant using it instead of “os.path.exits” (not “islink”). On Linux:

>>> targetpath = 'target'
>>> os.symlink('nonexistant', dst=targetpath)  # Make a broken symlink
>>> os.system('ls -l')
total 0
lrwxrwxrwx 1 vadmium vadmium 11 Jan  6 09:28 target -> nonexistant
0
>>> os.path.exists(targetpath)  # Doesn't register broken symlinks
False
>>> os.path.lexists(targetpath)  # Does register it
True

Did you try extracting a tar file over a broken link? (I haven’t tried your code; I’m just going on theory.)