Re: [gentoo-dev] Re: [RFC] Cleaning up PMS to have ${D} not end with a slash

[Gregory M. Turner]

On 4/15/2013 10:31 AM, Steven J. Long wrote:
> On Mon, Apr 15, 2013 at 12:01:24PM +0100, Ciaran McCreesh wrote:
>> On Mon, 15 Apr 2013 10:56:45 +0000
>> "Aaron W. Swenson" <titanofold@g.o> wrote:
>>> ROOT being a user set variable, having ROOT be an empty string by
>>> default still does not guarantee that ROOT won't end with a
>>> slash. Even if we change it so that it defaults to an empty string, it
>>> won't negate the need to do ${ROOT%/}/some/path.
>> The spec guarantees that ROOT will be non-empty and end in a slash. If
>> Portage isn't enforcing this, file a bug.
> Yes, but his point was this:
>
>>> The only thing that would help is if PMS defined that ROOT must not
>>> end with a slash.
>
> ie, let the mangler enforce empty or a valid directory not ending in a
> slash, which is hardly difficult, and makes ROOT easier to work with,
> along the lines of how any shellscripter would do it, similarly to the
> motivation for the change to D. Only with ROOT it's much more important
> that the path is correctly-formed for cross-platform compatibility.
That's how EPREFIX works; indeed, you don't need to do ${EPREFIX%/}, 
ever (unless, perhaps, we are manually scrubbing user inputs that 
haven't been scrubbed by portage).  Try it yourself: EPREFIX="/" 
portageq envvar EPREFIX.

If we "wanted to" do the same thing to {E,}ROOT we could, at least in 
future EAPIs.

However, given that ROOT is named "ROOT", "/" makes some kind of 
reasonable, intuitive sense.  I see double-slash mistakes involving ROOT 
here and there, but they are not hopelessly ubiquitous as they are with 
D, where, as Michał demonstrates in #465772, approximately 10 ebuilds in 
portage use the variable incorrectly for every 1 getting it right!

-gmt