From: Lars Schneider <larsxschneider@gmail.com>
To: "Jakub Narębski" <jnareb@gmail.com>
Cc: "Ramsay Jones" <ramsay@ramsayjones.plus.com>,
"Git Mailing List" <git@vger.kernel.org>,
"Jeff King" <peff@peff.net>,
"Torsten Bögershausen" <tboegi@web.de>,
mlbright@gmail.com
Subject: Re: [PATCH v1 3/3] convert: add filter.<driver>.useProtocol option
Date: Mon, 25 Jul 2016 22:32:39 +0200 [thread overview]
Message-ID: <7D0AD199-F077-4EB2-83A5-58EB603973CA@gmail.com> (raw)
In-Reply-To: <57954DA3.9090006@gmail.com>
On 25 Jul 2016, at 01:22, Jakub Narębski <jnareb@gmail.com> wrote:
> W dniu 2016-07-25 o 00:36, Ramsay Jones pisze:
>> On 24/07/16 18:16, Lars Schneider wrote:
>>> On 23 Jul 2016, at 01:19, Ramsay Jones <ramsay@ramsayjones.plus.com> wrote:
>>>> On 22/07/16 16:49, larsxschneider@gmail.com wrote:
> [...]
>>>>> This patch adds the filter.<driver>.useProtocol option which, if enabled,
>>>>> keeps the external filter process running and processes all blobs with
>>>>> the following protocol over stdin/stdout.
>>>>>
>>>>> 1. Git starts the filter on first usage and expects a welcome message
>>>>> with protocol version number:
>>>>> Git <-- Filter: "git-filter-protocol\n"
>>>>> Git <-- Filter: "version 1"
>>>>
>>>> Hmm, I was a bit surprised to see a 'filter' talk first (but so long as the
>>>> interaction is fully defined, I guess it doesn't matter).
>>>
>>> It was a conscious decision to have the `filter` talk first. My reasoning was:
>>>
>>> (1) I want a reliable way to distinguish the existing filter protocol ("single-shot
>>> invocation") from the new one ("long running"). I don't think there would be a
>>> situation where the existing protocol would talk first. Therefore the users would
>>> not accidentally mix them with a possibly half working, undetermined, outcome.
>>
>> If an 'single-shot' filter were incorrectly configured, instead of a new one, then
>> the interaction could last a little while - since it would result in deadlock! ;-)
>>
>> [If Git talks first instead, configuring a 'single-shot' filter _may_ still result
>> in a deadlock - depending on pipe size, etc.]
>
> Would it be possible to do an equivalent of sending empty file to the filter?
> If it is misconfigured old-style script, it would exit after possibly empty
> output; if not, we would start new-style interaction.
I think we would need to close the pipe to communicate "end" to the filter, no?
I would prefer to define the protocol explicitly as this is clearly easier.
>
> This should be, if we agree that detecting misconfigured filters is a good
> thing, tested.
>
>>>
>>> (2) In the future we could extend the pipe protocol (see $gmane/297994, it's very
>>> interesting). A filter could check Git's version and then pick the most appropriate
>>> filter protocol on startup.
Thanks,
Lars
next prev parent reply other threads:[~2016-07-25 20:32 UTC|newest]
Thread overview: 77+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-22 15:48 [PATCH v1 0/3] Git filter protocol larsxschneider
2016-07-22 15:48 ` [PATCH v1 1/3] convert: quote filter names in error messages larsxschneider
2016-07-22 15:48 ` [PATCH v1 2/3] convert: modernize tests larsxschneider
2016-07-26 15:18 ` Remi Galan Alfonso
2016-07-26 20:40 ` Junio C Hamano
2016-07-22 15:49 ` [PATCH v1 3/3] convert: add filter.<driver>.useProtocol option larsxschneider
2016-07-22 22:32 ` Torsten Bögershausen
2016-07-24 12:09 ` Lars Schneider
2016-07-22 23:19 ` Ramsay Jones
2016-07-22 23:28 ` Ramsay Jones
2016-07-24 17:16 ` Lars Schneider
2016-07-24 22:36 ` Ramsay Jones
2016-07-24 23:22 ` Jakub Narębski
2016-07-25 20:32 ` Lars Schneider [this message]
2016-07-26 10:58 ` Jakub Narębski
2016-07-25 20:24 ` Lars Schneider
2016-07-23 0:11 ` Jakub Narębski
2016-07-23 7:27 ` Eric Wong
2016-07-26 20:00 ` Jeff King
2016-07-24 18:36 ` Lars Schneider
2016-07-24 20:14 ` Jakub Narębski
2016-07-24 21:30 ` Jakub Narębski
2016-07-25 20:16 ` Lars Schneider
2016-07-26 12:24 ` Jakub Narębski
2016-07-25 20:09 ` Lars Schneider
2016-07-26 14:18 ` Jakub Narębski
2016-07-23 8:14 ` Eric Wong
2016-07-24 19:11 ` Lars Schneider
2016-07-25 7:27 ` Eric Wong
2016-07-25 15:48 ` Duy Nguyen
2016-07-22 21:39 ` [PATCH v1 0/3] Git filter protocol Junio C Hamano
2016-07-24 11:24 ` Lars Schneider
2016-07-26 20:11 ` Jeff King
2016-07-27 0:06 ` [PATCH v2 0/5] " larsxschneider
2016-07-27 0:06 ` [PATCH v2 1/5] convert: quote filter names in error messages larsxschneider
2016-07-27 20:01 ` Jakub Narębski
2016-07-28 8:23 ` Lars Schneider
2016-07-27 0:06 ` [PATCH v2 2/5] convert: modernize tests larsxschneider
2016-07-27 0:06 ` [PATCH v2 3/5] pkt-line: extract and use `set_packet_header` function larsxschneider
2016-07-27 0:20 ` Junio C Hamano
2016-07-27 9:13 ` Lars Schneider
2016-07-27 16:31 ` Junio C Hamano
2016-07-27 0:06 ` [PATCH v2 4/5] convert: generate large test files only once larsxschneider
2016-07-27 2:35 ` Torsten Bögershausen
2016-07-27 13:32 ` Jeff King
2016-07-27 16:50 ` Lars Schneider
2016-07-27 0:06 ` [PATCH v2 5/5] convert: add filter.<driver>.process option larsxschneider
2016-07-27 1:32 ` Jeff King
2016-07-27 17:31 ` Lars Schneider
2016-07-27 18:11 ` Jeff King
2016-07-28 12:10 ` Lars Schneider
2016-07-28 13:35 ` Jeff King
2016-07-27 9:41 ` Eric Wong
2016-07-29 10:38 ` Lars Schneider
2016-07-29 11:24 ` Jakub Narębski
2016-07-29 11:31 ` Lars Schneider
2016-08-05 18:55 ` Eric Wong
2016-08-05 23:26 ` Lars Schneider
2016-08-05 23:38 ` Eric Wong
2016-07-27 23:31 ` Jakub Narębski
2016-07-29 8:04 ` Lars Schneider
2016-07-29 17:35 ` Junio C Hamano
2016-07-29 23:11 ` Jakub Narębski
2016-07-29 23:44 ` Lars Schneider
2016-07-30 9:32 ` Jakub Narębski
2016-07-28 10:32 ` Torsten Bögershausen
2016-07-27 19:08 ` [PATCH v2 0/5] Git filter protocol Jakub Narębski
2016-07-28 7:16 ` Lars Schneider
2016-07-28 10:42 ` Jakub Narębski
2016-07-28 13:29 ` Jeff King
2016-07-29 7:40 ` Jakub Narębski
2016-07-29 8:14 ` Lars Schneider
2016-07-29 15:57 ` Jeff King
2016-07-29 16:20 ` Lars Schneider
2016-07-29 16:50 ` Jeff King
2016-07-29 17:43 ` Lars Schneider
2016-07-29 18:27 ` Jeff King
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