From: "Ævar Arnfjörð Bjarmason" <avarab@gmail.com>
To: Jeff King <peff@peff.net>
Cc: Junio C Hamano <gitster@pobox.com>,
git@vger.kernel.org, The Grey Wolf <greywolf@starwolf.com>,
"Randall S . Becker" <rsbecker@nexbridge.com>
Subject: Re: [PATCH] config: add an includeIf.env{Exists,Bool,Is,Match}
Date: Tue, 28 Sep 2021 01:52:26 +0200 [thread overview]
Message-ID: <87lf3hzhkr.fsf@evledraar.gmail.com> (raw)
In-Reply-To: <YVImeFHxY7hmb3wY@coredump.intra.peff.net>
On Mon, Sep 27 2021, Jeff King wrote:
> On Mon, Sep 27, 2021 at 09:30:41AM -0700, Junio C Hamano wrote:
>
>> >> This asserts what? FOO=" bar"?
>> >
>> > Whoops, that should have been "envIs", asserting that $FOO contains
>> > "bar".
>>
>> Oh, "can we check with a literal with leading whitespace?" was what
>> my question was about ;-)
>
> My assumption was that nobody would really care about doing so. It is
> true that it's less flexible, though (and is a decision we can't easily
> take back later).
Yeah, I think nobody really cares about stripspace() or not for this
sort of feature.
I do think having implicit and explicit complexity like that makes it
harder to document, implement and understand for users though. I.e. is
"env:FOO == bar" the same as "env:FOO ==bar" etc., what whitespace
exactly is accepted etc.
>> > As I said, I think it matters more with the infix operators, as:
>> >
>> > [includeIf "env:FOO == bar"]
>> >
>> > is more readable than:
>> >
>> > [includeIf "env:FOO==bar"]
>>
>> Sure, but at that point, we'd probably want some quoting mechanism
>> for the literal to be compared, e.g.
>>
>> [includeIf "env:PATH ~= \"(:|^)/usr/bin(:|$)\""]
>
> Ick. The extra quoting of the internal double-quotes is pretty horrid to
> look at. Also, how does one match a double-quote in the value? \\\"?
>
> If it were optional, that would make the common cases easy (no dq, no
> whitespace), and the hard ones possible.
An implicit assumption of mine in the simpler positive-match-only
version (which I should have made clear) is that anyone who needs this
sort of complexity can just arrange to wrap their "git" in a function,
or do this sort of thing in their ~/.bashrc, i.e. just:
if code_of_arbitrary_complexity
then
export GIT_DO_XYZ_INCLUDES=1
fi
Then in your config:
includeIf.envBool:GIT_DO_XYZ_INCLUDES.path=~/.gitconfig.d/xyz.cfg
And having written that out I think the best thing to do is probably to
have a version that only does the envExists and envBool version (or just
envBool), and skip envIs and envMatch entirely.
In the case of env:PATH we're just setting users up for some buggy or
unexpected interaction with something that would be better done either
via a gitdir include, or if they really need $PATH they can just wrap
"git" in a function that sets a boolean inclusion variable.
That would get us out of having to support emergent behavior where some
git tool invoked via run_command() or something chdir's somewhere as an
implementation detail, and such an env:PATH match means we'd need to
support that, or potentially break existing user config.
Or, since we might not be invoked via a shell, the same issue with a
$PATH being "stale" from the POV of a user who's wondering why say a
command like:
# status in the "t" subdirectory
git -C t <cmd> <question>
Doesn't have the "right" $PWD, which we might not have as some future
shortcut in <cmd> decided not to bother chdir()-ing to answer the user's
<question>.
> I think this is getting into a bit of a digression, though. I'm willing
> to defer to Ævar, who is doing the actual work, and I don't know if he
> has found any of this compelling. ;)
>
>> > But I do think:
>> >
>> > [includeIf "envIs:FOO:bar"]
>> >
>> > is harder to read than even:
>> >
>> > [includeIf "envIs:FOO: bar"]
>>
>> Hmph, that's quite subjective, I am afraid. When I see the latter
>> in the configuration file, "do I have to have a single space before
>> 'bar' in the value of $FOO" would be the first question that would
>> come to my mind.
>
> I think it's just the mashed-up colons that I find ugly in the first
> one. But I agree the latter isn't that nice either, and introduces the
> ambiguity you describe.
FWIW I hacked up a --config-key --config-value pairing so you could set
keys with "=" in them on the command-line, I'm not sure I like the
interface, but it gets rid of that ":" v.s. "=" edge case:
https://github.com/avar/git/commit/a86053df48b
>> With an understanding that our syntax is so limited that we cannot
>> even write '=' and need to resort to Is: instead, I'd actually find
>> that the former less confusing than the latter.
>
> That I think is the most interesting question: is the "=" actually
> out-of-bounds? I tend to think not, based on our responses earlier in
> the thread.
next prev parent reply other threads:[~2021-09-28 0:09 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-23 5:21 ANSI sequences produced on non-ANSI terminal The Grey Wolf
2021-09-23 21:20 ` Jeff King
2021-09-23 21:54 ` Junio C Hamano
2021-09-23 22:04 ` Randall S. Becker
2021-09-25 6:45 ` Kevin Daudt
2021-09-24 0:58 ` [PATCH] config: add an includeIf.env{Exists,Bool,Is,Match} Ævar Arnfjörð Bjarmason
2021-09-24 21:07 ` Jeff King
2021-09-24 21:28 ` Junio C Hamano
2021-09-24 21:59 ` Jeff King
2021-09-27 16:30 ` Junio C Hamano
2021-09-27 20:15 ` Jeff King
2021-09-27 20:53 ` Randall S. Becker
2021-09-27 21:37 ` Jeff King
2021-09-27 21:56 ` Randall S. Becker
2021-09-27 23:52 ` Ævar Arnfjörð Bjarmason [this message]
2021-09-28 0:41 ` Jeff King
2021-09-28 2:42 ` Ævar Arnfjörð Bjarmason
2021-09-28 5:42 ` Jeff King
2021-09-28 19:28 ` Ævar Arnfjörð Bjarmason
2021-09-28 0:24 ` Junio C Hamano
2021-09-24 23:57 ` ANSI sequences produced on non-ANSI terminal Greywolf
2021-09-25 5:49 ` Jeff King
2021-10-01 23:17 ` Greywolf
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
List information: http://vger.kernel.org/majordomo-info.html
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=87lf3hzhkr.fsf@evledraar.gmail.com \
--to=avarab@gmail.com \
--cc=git@vger.kernel.org \
--cc=gitster@pobox.com \
--cc=greywolf@starwolf.com \
--cc=peff@peff.net \
--cc=rsbecker@nexbridge.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
Code repositories for project(s) associated with this public inbox
https://80x24.org/mirrors/git.git
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).