On Tue, Oct 10, 2017 at 09:51:38PM +0900, Junio C Hamano wrote:
> Jeff King <peff@xxxxxxxx> writes:
>
> > :( I was worried that this might hit some third-party scripts.
> > ...
> > All that said, should we revisit the decision from 6be4595edb? The two
> > code changes we could make are:
> >
> > 1. Adding a "--color" option to "git status". Commit 0c88bf5050
> > (provide --color option for all ref-filter users, 2017-10-03) from
> > that same series shows some prior art.
> >
> > This is a clean solution, but it does mean that scripts have to
> > adapt (and would potentially need to care about which Git version
> > they're relying on).
>
> If we view that "always" issue is a regression, then this is not a
> "solution". It is a part of an ideal world where we never allowed
> "always" as a value for color.ui, which is not the world we live in.
Right, this doesn't solve any regression. It solves the "there's no way
to do this thing I might want to" that exists in either world (one where
"always" never existed, or one where "always" does not do that anymore
but we accept it as either not a regression or an acceptable
regression).
> > 2. Re-allow "color.always" config from the command-line. It's actually
> > on-disk config that we want to downgrade, but I wanted to avoid
> > making complicated rules about how the config would behave in
> > different scopes. The patch for this would look something like the
> > one below.
>
> Yuck, ugly. The code is simple (thanks to the "who ordered it?"
> thing), but the behaviour is rather embarrassing to explain.
Yes, it's definitely the most ugly of all the options. The reason I
mention it is that it's also the only one that solves the "git -c
color.ui=always" regression (if we consider it one) without making a
huge and risky change.
> > 3. Revert the original series, and revisit the original "respect
> > color.ui via porcelain" commit which broke add--interactive in
> > v2.14.2 (136c8c8b8fa).
>
> Which one do you mean is "the original series"? The one that made
> plumbing to pay attention to the color config?
No, I meant reverting jk/ui-color-always-to-auto. But if we revert that,
it leaves "add -p" broken when you set color.ui=always. So we must
either accept that, or _also_ revert 136c8c8b8fa and come up with a
different solution.
> I think it would be
> the cleanest "solution" in the world we live in, but the series (and
> the follow-on changes that started assuming that config_default
> reads the color config) have a rather large footprint and it will be
> quite painful to vet the result.
I agree that is a risk. It might not be _too_ bad, though this is an
area that historically has poor test coverage. I know that for-each-ref
and tag are two that would need touched (and it was them that led me
down to the path to 136c8c8b8fa in the first place).
> I think the right fix to the original problem (you cannot remove
> auto-color from the plumbing) is to stop paying attention to color
> configuration from the default config. I wonder if something like
> this would work?
>
> - Initialize color.c::git_use_color_default to GIT_COLOR_UNKNOWN;
>
> - When git_color_config() is called, and if git_use_color_default
> is still GIT_COLOR_UNKNOWN, set it to GIT_COLOR_AUTO (regardless
> of the variable git_color_config() is called for).
>
> - In color.c::want_color(), when git_use_color_default is used,
> notice if it is GIT_COLOR_UNKNOWN and behave as if it is
> GIT_COLOR_NEVER.
>
> Then we make sure that git_color_config() is never called by any
> plumbing command. The fact it is (ever) called can be taken as a
> clue that we are running a Porcelain (hence we transition from
> UNKNOWN to AUTO), so we'd get the desirable "no default color for
> plumbing, auto color for Porcelain", I would think.
Yes, I think that's the simplest way to implement the "plumbing should
never do color without a command-line option" scheme.
I do wonder if people would end up seeing some corner cases as
regressions, though. Right now "diff-tree" _does_ color the output by
default, and it would stop doing so under your scheme. That's the right
thing to do by the plumbing/porcelain distinction, but users with
scripts that use diff-tree (or other plumbing) to generate user-visible
output may unexpectedly lose their color, until the calling script is
fixed to add back in a --color option[1].
-Peff
[1] Actually, just saying "--color" isn't enough, since you'd want to
respect the user's color options. add--interactive does this, but
it's a slight pain. It would be nice to have a --color=config
variant that just calls git_color_config(). But if we are talking
regression-fixes before v2.15, I don't think we need to have such
niceties.
