A setting for "Show directory sizes" to ignore mount points

[birdie-github]

Is there an existing request for this?

• I have searched the existing issues

Is your feature request related to a problem?

Currently, Show directory sizes includes the sizes of files found in mounted filesystems.

In practice, this often produces unintuitive or misleading results (e.g. double-counting via pulling in unrelated filesystems via mount points). Most users expect a directory size to reflect the contents physically belonging to that directory tree.

It would be useful to have an option to exclude mount points from size calculation.

Hard links are a special case: excluding them reliably would require global inode tracking, and double-counting is effectively unavoidable without that context. Keeping hard links included is therefore reasonable.

Describe the solution you'd like

An option in Options -> Configuration to do exactly that.

Akin to One filesystem only or Ignore mount points or Do not descend into mount points

Describe alternatives you've considered

None.

Additional context

This would also align more closely with du -x / --one-file-system semantics.

[mc-worker]

Related to #3647.

[zyv]

Related to #4987.

[birdie-github]

A totally untested patch:

mc_mountpoints.patch

[egmontkob]

(I haven't tested the patch.)

Most users expect a directory size to reflect the contents physically belonging to that directory tree.

I'm not sure I agree with the "most users" part. I personally find the current behavior more useful, while surely there are valid use cases for the other.

A nontrivial followup question (I don't know what du -x does here, nor what your patch does): Should it descend to directories that are locally under the same mount point, but remotely under a dfferent one, as per #4987?

And a slight usability concern: If it's a global mc setting, you might have forgotten what you set it to when you invoke this function. Therefore you might have the incorrect idea about what you actually measured. IMO, preferably, either there should be no global setting but two (or even three) different actions (like e.g. how Copy, Move, Compare directories, Find file etc. ask you how to perform that operation; although such a dialog would be super annoying if you use the Ctrl+Space shortcut many times in a row), or the UI should somehow reflect which operation was performed (maybe only if they'd differ, i.e. when a mount point was actually found). I'm really not sure how it could be done nicely.