followup on native symlink support

[Corinna Vinschen]

Hi James,

On Oct  1 08:49, James Gregurich wrote:
> hi.
> 
> 
> I've been using a recent version of cygwin with
> CYGWIN=winsymlinks:native setting for daily work for some weeks. I
> haven't experienced any problems with the feature. Its always worked
> as expected. I think you made a good choice to depart from my original
> design recommendation on converting relative paths that exceed
> PATH_MAX to "\??\" tagged absolute paths.
  ^^^^^^^^
  I assume you mean MAX_PATH, the Windows 260 chars value, rather than
  PATH_MAX, the POSIX variation which is set to 4096 on Cygwin.

This isn't quite as it is implemented, actually.  In fact, Cygwin will
produce relative native symlinks, if the underlying native source and
target paths of the symlink share a common path prefix.  It can do so
without taking MAX_PATH into account, because, to the best of my
knowledge, the Windows implementation of native symlinks doesn't share
this relative path length restriction with the other file API calls.

However, if the underlying native source and target paths do *not* share
a common path prefix, Cygwin has no choice but to create the symlink as
an absolute symlink.  Consider a POSIX path which points to another
drive via /etc/fstab.  Something like

  foo -> ../baz/bar

could easily translate into

  C:\foo -> D:\bar

There's no way to express this as relative path.

> We have since run into some
> use cases where that caused undesirable behavior. It caused symlinks
> that were specific to particular users on particular systems to get
> committed to our repository.
> 
> 
> I wanted to write in to thank Corrina and the other cygwin maintainers

s/rrin/rinn/


Thanks,
Corinna

-- 
Corinna Vinschen                  Please, send mails regarding Cygwin to
Cygwin Maintainer                 cygwin AT cygwin DOT com
Red Hat
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