cp: when multiple flags are specified only the final one should take effect

[ChrisDryden]

Problem

GNU cp states: "If more than one of -H, -L, and -P is specified, only the final one takes effect."

Currently in uutils, -H and -P/-L are tracked independently, so combining them doesn't respect flag ordering. For example, -HP should have -P win (don't follow symlinks), but both flags end up being set.

Example:

mkdir test && cd test
echo "content" > file.txt
ln -s file.txt symlink

GNU:

  cp -HP symlink dest_hp
  file dest_hp # dest_hp: symbolic link to file.txt


  cp -PH symlink dest_ph
  file dest_ph # dest_ph: ASCII text

uutils

  uutils-cp -HP symlink dest_hp_uu
  file dest_hp_uu # dest_hp_uu: ASCII text  (WRONG - should be symlink)

This was partially inspired by the Busybox HLP test where this is one of the two issues that's causing it not to pass, the other part of it is way more complicated but this one should just be able to be fixed by updating the overrides_with_all notation in the clap builder and would be a good first issue for a new contributor that's at the uutils rustnyc workshop

[ChrisDryden]

Look like this has been partially addressed in the past, I'm wondering if more flags need to be checked like this: #2998

[ChrisDryden]

Going down the rabbit hole, there's so many other utilities that share this type of behaviour and I think theres actually more than just these three for this utility

[ChrisDryden]

@Dylans123 is running through the different options now, to come up with tests to see which ones cp is missing, we will have to go through the other utilities at some point too

[ChrisDryden]

Looks like -a and -d should also be in the override chain, then in the the override policy -i -n -f are in a group and its currently missing -f

[ChrisDryden]

@abhilov23 if you're looking for a very straightforward first contribution, you can use what @Dylans123 did for hlp as an example and do that for -i -n -f?