Re: [gentoo-dev] relative ROOT: correct behavior when ROOT=

[Ulrich Mueller]

>>>>> On Thu, 06 Sep 2012, Gregory M Turner wrote:

> Hello, in my overlay I need to fix a bunch of issues that crop up when
> implementing EPREFIX construction in scripts due to Cygwin's
> idiosyncratic, but POSIX-compliant, handling of paths beginning with
> "//" (Cygwin does some arguably pathological stuff when such paths are
> used).

> Almost all of these stem from the careless tacking of "ROOT" onto
> "EPREFIX" in bash-scripts, i.e., as in this (made-up) bash-script snippet:

> ${ROOT:=/}
> EPREFIX="@GENTOO_PORTAGE_EPREFIX@"
> EROOT="${ROOT}${EPREFIX}"

> When ROOT is undefined or empty, this script will assign "//foo" to
> EROOT and bad things will happen in Cygwin.

> Several correct-ish solutions exist, i.e., in the above we could change
> the concatenation statement to read:

> EROOT="${ROOT}${EPREFIX#/}"

I'd rather do it the other way around:
EROOT=${ROOT%/}${EPREFIX}

Reason: EPREFIX is guaranteed to start with a slash, whereas for ROOT
I wouldn't be so sure that it always ends with one.

Ulrich