From: <rsbecker@nexbridge.com>
To: "'Felipe Contreras'" <felipe.contreras@gmail.com>
Cc: <phillip.wood@dunelm.org.uk>, "'demerphq'" <demerphq@gmail.com>,
"'Junio C Hamano'" <gitster@pobox.com>,
"'Emily Shaffer'" <nasamuffin@google.com>,
"'Git List'" <git@vger.kernel.org>,
"'Jonathan Nieder'" <jrn@google.com>,
"'Jose Lopes'" <jabolopes@google.com>,
"'Aleksandr Mikhailov'" <avmikhailov@google.com>
Subject: RE: Proposal/Discussion: Turning parts of Git into libraries
Date: Fri, 24 Mar 2023 15:27:51 -0400 [thread overview]
Message-ID: <004d01d95e86$bd355d40$37a017c0$@nexbridge.com> (raw)
In-Reply-To: <CAMP44s3Gk67rPEPjoAxLHS4KrCQBb6VoPJ6Rqm-FTK+8PTaRRQ@mail.gmail.com>
On Thursday, March 23, 2023 7:55 PM, Felipe Contreras wrote:
>On Thu, Mar 23, 2023 at 5:43 PM <rsbecker@nexbridge.com> wrote:
>>
>> On Thursday, March 23, 2023 7:35 PM, Felipe Contreras wrote:
>> >On Thu, Mar 23, 2023 at 5:30 PM <rsbecker@nexbridge.com> wrote:
>> >>
>> >> On Thursday, March 23, 2023 7:22 PM, Felipe Contreras wrote:
>> >> >On Sat, Feb 18, 2023 at 5:12 AM Phillip Wood
>> >> ><phillip.wood123@gmail.com>
>> >wrote:
>> >> >>
>> >> >> On 18/02/2023 01:59, demerphq wrote:
>> >> >> > On Sat, 18 Feb 2023 at 00:24, Junio C Hamano <gitster@pobox.com>
>wrote:
>> >> >> >>
>> >> >> >> Emily Shaffer <nasamuffin@google.com> writes:
>> >> >> >>
>> >> >> >>> Basically, if this effort turns out not to be fruitful as a
>> >> >> >>> whole, I'd like for us to still have left a positive impact on the codebase.
>> >> >> >>> ...
>> >> >> >>> So what's next? Naturally, I'm looking forward to a spirited
>> >> >> >>> discussion about this topic - I'd like to know which
>> >> >> >>> concerns haven't been addressed and figure out whether we
>> >> >> >>> can find a way around them, and generally build awareness of
>> >> >> >>> this effort with the
>> >community.
>> >> >> >>
>> >> >> >> On of the gravest concerns is that the devil is in the details.
>> >> >> >>
>> >> >> >> For example, "die() is inconvenient to callers, let's
>> >> >> >> propagate errors up the callchain" is an easy thing to say,
>> >> >> >> but it would take much more than "let's propagate errors up"
>> >> >> >> to libify something like
>> >> >> >> check_connected() to do the same thing without spawning a
>> >> >> >> separate process that is expected to exit with failure.
>> >> >> >
>> >> >> >
>> >> >> > What does "propagate errors up the callchain" mean? One
>> >> >> > interpretation I can think of seems quite horrible, but
>> >> >> > another seems quite doable and reasonable and likely not even
>> >> >> > very invasive of the existing code:
>> >> >> >
>> >> >> > You can use setjmp/longjmp to implement a form of "try", so
>> >> >> > that errors dont have to be *explicitly* returned *in* the call chain.
>> >> >> > And you could probably do so without changing very much of the
>> >> >> > existing code at all, and maintain a high level of conceptual
>> >> >> > alignment with the current code strategy.
>> >> >>
>> >> >> Using setjmp/longjmp is an interesting suggestion, I think lua
>> >> >> does something similar to what you describe for perl. However I
>> >> >> think both of those use a allocator with garbage collection. I
>> >> >> worry that using longjmp in git would be more invasive (or
>> >> >> result in more memory leaks) as we'd need to to guard each
>> >> >> allocation with some code to clean it up and then propagate the
>> >> >> error. That means we're back to manually propagating errors up the call
>chain in many cases.
>> >> >
>> >> >We could just use talloc [1].
>> >>
>> >> talloc is not portable.
>> >
>> >What makes you say that?
>>
>> talloc is not part of a POSIX standard I could find.
>
>It's a library, like: z, ssl, curl, pcre2-8, etc. Libraries can be compiled on different
>platforms.
talloc adds additional *required* dependencies to git, including python3 - required to configure and build talloc - which is not available on the NonStop ia64 platform (required support through end of 2025). I must express my resistance to what would amount to losing support for git on this NonStop platform.
--Randall
next prev parent reply other threads:[~2023-03-24 19:28 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-17 21:12 Proposal/Discussion: Turning parts of Git into libraries Emily Shaffer
2023-02-17 21:21 ` brian m. carlson
2023-02-17 21:38 ` Emily Shaffer
2023-02-17 22:41 ` brian m. carlson
2023-02-17 22:49 ` Emily Shaffer
2023-02-22 19:34 ` Jeff King
2023-02-24 20:31 ` Emily Shaffer
2023-02-24 21:41 ` Jeff King
2023-02-24 22:59 ` Junio C Hamano
2023-02-17 22:04 ` rsbecker
2023-02-17 22:48 ` brian m. carlson
2023-02-17 22:57 ` Junio C Hamano
2023-02-18 1:59 ` demerphq
2023-02-18 10:36 ` Phillip Wood
2023-03-23 23:22 ` Felipe Contreras
2023-03-23 23:30 ` rsbecker
2023-03-23 23:34 ` Felipe Contreras
2023-03-23 23:42 ` rsbecker
2023-03-23 23:55 ` Felipe Contreras
2023-03-24 19:27 ` rsbecker [this message]
2023-03-24 21:21 ` Felipe Contreras
2023-03-24 22:06 ` rsbecker
2023-03-24 22:29 ` Felipe Contreras
2023-02-21 21:42 ` Emily Shaffer
2023-02-22 0:22 ` Junio C Hamano
2023-02-18 4:05 ` Elijah Newren
2023-02-21 22:06 ` Emily Shaffer
2023-02-22 8:23 ` Elijah Newren
2023-02-22 19:25 ` Jeff King
2023-02-21 19:09 ` Taylor Blau
2023-02-21 22:27 ` Emily Shaffer
2023-02-22 1:44 ` Victoria Dye
2023-02-25 1:48 ` Jonathan Tan
2023-02-22 14:55 ` Derrick Stolee
2023-02-24 21:06 ` Emily Shaffer
2023-03-23 23:37 ` Felipe Contreras
2023-03-23 23:44 ` rsbecker
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