Adopt whole folders

[mrkgnao]

Allow stow --adopt to adopt a folder if I try to stow a folder that already exists.

[aspiers]

I think that would be too dangerous to enable in general. Whilst a lot of Stow packages share top-level directories such as bin/, lib/, that wouldn't necessarily be a problem because we could make it avoid adopting folders which are already controlled by Stow. But it would often be a problem the first time any package was stowed into a given target directory, e.g. if ~/bin/ or /usr/local/bin already existed and contained files or directories which should not be adopted into the package being stowed.

Maybe we could allow this in carefully controlled circumstances, such as --adopt-folder=bin, but then how is that any better than just doing

mv $target_dir/bin $stow_package

before running a normal stow command? So I'm not convinced the benefits of implementing this outweigh the dangers. However I'm very willing to be persuaded otherwise, if you can give a concrete real-world example which explains your use case!

[aspiers]

Borrowing from ideas in #24, maybe the benefits are worth it after all:

• verify that the target_dir file is not a symlink (which needs to be smarter, it should actually check if it's a non-stow symlink)
• verify that the stow_package contains the appropriate parent dirs (essentially mkdir -p $(dirname ...))
• bail if the directory already exists in the package, rather than accidentally moving the new one from the target directory to underneath the existing one in the package tree.

So I think I'm now persuaded otherwise - pull requests very welcome!