From: <rsbecker@nexbridge.com>
To: "'Felipe Contreras'" <felipe.contreras@gmail.com>,
<phillip.wood@dunelm.org.uk>
Cc: "'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: Thu, 23 Mar 2023 19:30:30 -0400 [thread overview]
Message-ID: <008101d95ddf$7863d900$692b8b00$@nexbridge.com> (raw)
In-Reply-To: <CAMP44s1Qqd2cYcf7OGxz1-PY-8TF2KG+9jPEWMrnCaCfPe_1sw@mail.gmail.com>
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. This would break various platforms.
--Randall
next prev parent reply other threads:[~2023-03-23 23:30 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 [this message]
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
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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