Re: [gentoo-dev] bash-4.4 - call for testers

[Kent Fredric]

On Sun, 2 Oct 2016 16:03:11 +0800
konsolebox <konsolebox@×××××.com> wrote:

> I actually don't like the idea of enabling or disabling
> "installed-readline" based on the `${PV} != *_rc*` condition.  If a
> user would want to explicitly enable "installed-readline" globally,
> how would he make sure that it only affects the release version of
> bash?  I suggest that we just don't entertain the flag (and not make
> it available) if the ebuild is not targetting a release version, and
> not use the readline installed by the system by default.  No one would
> need a non-release version of bash compiled against a system readline
> anyway.

That's not what that does.  It doesn't enable or disable the mechanic,
the code I offered only changes the default for _rc.

That is, on _rc the default is "use bundled readline implementation",
and on non_rc, the default is "use pre-existing readline
implementation".

if the user specifies an explicit

    USE="system-readline"  

in make.conf or /etc/portage/package.use, then this "default" gets
overridden and the system readline implementation is always used.

if the user speciifies an explicit

    USE="-system-readline" 

in make.conf or /etc/portage/package.use, then this "default" gets
overriden and the inbuilt readline is awlays used.

Explicitly defined configuration always trumps IUSE. The "+" prefix in
IUSE only specifies that the USE flag defaults to on, as opposed to
defaulting off.

>
> I also thought using 'system-' prefix is confusing.  Does that mean
> the system of the machine, or the system of the application?  In
> firefox, I once thought that system-* means packages bundled within
> it.  Perhaps I misread, or perhaps it was changed.  At that time,
> descriptions of use flags were not widely provided yet so I could only
> guess it based on how I built the packages.

The system of the machine. As in, "Operating System". Always.
"system-foo" usually means "foo is bundled, and toggling this flag
toggles between using the bundled foo, or the system foo.

>
> But I don't really mind which one is used.  I also just thought
> 'installed-readline' is better since it configures
> `--with-installed-readline`, so one can simply have `$(use_enable
> installed-readline)` if applicable.

'use_enable' takes a USE flag and a configure token anyway. 

So:

    $(use_enable system-readline installed-readline)

is equivalent to:

     use system-readline && myconf+=" --enable-installed-readline"

But you probably wanted "use_with" ( man 5 ebuild )

    $(use_with system-readline installed-readline)

Which is instead equivalent to

    use system-readline && myconf+=" --with-installed-readline"