Use SUDO_COMMAND to check for sudo

[docwhat]

sudo -n true only checks that we could use sudo, not if we are in
a sudo session.

closes #852

[dritter]

Thanks @docwhat for that PR.

As @onaforeignshore pointed out, the prompt_user segment has a sudo state as well. Could you change that as well?

[docwhat]

@dritter Done.

[dritter]

Awesome! Will merge that later in #944 today.

[bhilburn]

@docwhat - Thanks so much for putting this together. I really do appreciate it, and it'll be included in the v0.6.6 release that we will get out the door ASAP.

@dritter - nice job catching that comment from @onaforeignshore in the other PR! That would have been easy to miss, and thanks for staging this for v0.6.6 release =)

[bhilburn]

Merged into master as part of #944, and will be part of the v0.6.6 release!

[tippl]

This might be kicking a dead thread, sorry about that, but it seems the SUDO state was misunderstood a bit.

Original idea of the state was to have a yellow prompt if the sudo has cached user creds, as such "danger, sudo in this terminal will not ask password" thus the "can i run sudo" implementation.

$SUDO_COMMAND is set by sudo for processes started by sudo, thus does not reflect the functionality.

For it to be set, zsh would have to run in a sudo session, however that means the process has root permissions, so the ROOT state is used instead here, making the SUDO state not used at all.

I do not know if it is possible to implement this feature without incurring the "password is required" line in log, so i am not against removing the feature entirely, just mentioning this here so we don't have dead code that does nothing.