From: "Torsten Bögershausen" <tboegi@web.de>
To: larsxschneider@gmail.com
Cc: git@vger.kernel.org, peff@peff.net, gitster@pobox.com,
sbeller@google.com, Johannes.Schindelin@gmx.de, jnareb@gmail.com,
mlbright@gmail.com, jacob.keller@gmail.com
Subject: Re: [PATCH v7 10/10] convert: add filter.<driver>.process option
Date: Sat, 10 Sep 2016 06:29:20 +0000 [thread overview]
Message-ID: <20160910062919.GB11001@tb-raspi> (raw)
In-Reply-To: <20160908182132.50788-11-larsxschneider@gmail.com>
On Thu, Sep 08, 2016 at 08:21:32PM +0200, larsxschneider@gmail.com wrote:
[]
> +packet: git> git-filter-client
> +packet: git> version=2
> +packet: git> version=42
> +packet: git> 0000
> +packet: git< git-filter-server
> +packet: git< version=2
> +packet: git> clean=true
> +packet: git> smudge=true
> +packet: git> not-yet-invented=true
> +packet: git> 0000
> +packet: git< clean=true
> +packet: git< smudge=true
> +packet: git< 0000
It's probalby only me who has difficulties to distinguish
'>' from '<'.
packet: git> git-filter-client
packet: git> version=2
packet: git> version=42
packet: git> 0000
packet: filter> git-filter-server
packet: filter> version=2
(Otherwise the dialoge description is nice)
> +------------------------
> +Supported filter capabilities in version 2 are "clean" and
> +"smudge".
> +
> +Afterwards Git sends a list of "key=value" pairs terminated with
> +a flush packet. The list will contain at least the filter command
> +(based on the supported capabilities) and the pathname of the file
> +to filter relative to the repository root. Right after these packets
> +Git sends the content split in zero or more pkt-line packets and a
> +flush packet to terminate content.
> +------------------------
> +packet: git> command=smudge\n
> +packet: git> pathname=path/testfile.dat\n
How do we send pathnames the have '\n' ?
Not really recommended, but allowed.
And here I am a little bit lost, is each of the lines packed into
a pkt-line ?
command=smudge is packet as pkt-line and pathname= is packed into
another one ? (The we don't need the '\n' at all)
Or go both lines into one pkt-line (thats what I think), then
we don't need the '\n' afther the pathname.
And in this case the pathname is always the last element, and a '\n'
may occur in the pathname, since we know the length of the packet
we know how long the pathname must be.
> +packet: git> 0000
> +packet: git> CONTENT
> +packet: git> 0000
> +------------------------
> +
> +The filter is expected to respond with a list of "key=value" pairs
> +terminated with a flush packet. If the filter does not experience
> +problems then the list must contain a "success" status. Right after
> +these packets the filter is expected to send the content in zero
> +or more pkt-line packets and a flush packet at the end. Finally, a
> +second list of "key=value" pairs terminated with a flush packet
> +is expected. The filter can change the status in the second list.
> +------------------------
> +packet: git< status=success\n
> +packet: git< 0000
> +packet: git< SMUDGED_CONTENT
> +packet: git< 0000
> +packet: git< 0000 # empty list!
> +------------------------
> +
> +If the result content is empty then the filter is expected to respond
> +with a success status and an empty list.
> +------------------------
> +packet: git< status=success\n
> +packet: git< 0000
> +packet: git< 0000 # empty content!
> +packet: git< 0000 # empty list!
> +------------------------
> +
> +In case the filter cannot or does not want to process the content,
Does not want ?
I can see something like "I read through the file, there is nothing
to do. So Git, I don't send anything back, you know where the file is.
> +it is expected to respond with an "error" status. Depending on the
> +`filter.<driver>.required` flag Git will interpret that as error
> +but it will not stop or restart the filter process.
> +------------------------
> +packet: git< status=error\n
> +packet: git< 0000
> +------------------------
> +
> +If the filter experiences an error during processing, then it can
> +send the status "error" after the content was (partially or
> +completely) sent. Depending on the `filter.<driver>.required` flag
> +Git will interpret that as error but it will not stop or restart the
> +filter process.
> +------------------------
> +packet: git< status=success\n
> +packet: git< 0000
> +packet: git< HALF_WRITTEN_ERRONEOUS_CONTENT
> +packet: git< 0000
> +packet: git< status=error\n
> +packet: git< 0000
> +------------------------
> +
> +If the filter dies during the communication or does not adhere to
> +the protocol then Git will stop the filter process and restart it
My personal comment:
When a filter is mis-behaving, Git should say so loud and clear, and
die().
The filter process can be left running, so that it can be debugged.
Here I stopped the review for a moment,
I still think that Git shouldn't kill anything, because we loose
the ability to debug these processes.
next prev parent reply other threads:[~2016-09-10 6:29 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-09-08 18:21 [PATCH v7 00/10] Git filter protocol larsxschneider
2016-09-08 18:21 ` [PATCH v7 01/10] pkt-line: rename packet_write() to packet_write_fmt() larsxschneider
2016-09-08 18:21 ` [PATCH v7 02/10] pkt-line: extract set_packet_header() larsxschneider
2016-09-08 18:21 ` [PATCH v7 03/10] pkt-line: add packet_write_fmt_gently() larsxschneider
2016-09-08 21:18 ` Stefan Beller
2016-09-11 11:36 ` Lars Schneider
2016-09-11 16:01 ` Stefan Beller
2016-09-12 9:22 ` Lars Schneider
2016-09-08 18:21 ` [PATCH v7 04/10] pkt-line: add packet_flush_gently() larsxschneider
2016-09-12 23:30 ` Junio C Hamano
2016-09-13 22:12 ` Lars Schneider
2016-09-13 22:44 ` Junio C Hamano
2016-09-15 16:42 ` Lars Schneider
2016-09-15 19:44 ` Jeff King
2016-09-15 20:19 ` Lars Schneider
2016-09-15 20:33 ` Junio C Hamano
2016-09-08 18:21 ` [PATCH v7 05/10] pkt-line: add packet_write_gently() larsxschneider
2016-09-08 21:24 ` Stefan Beller
2016-09-11 11:44 ` Lars Schneider
2016-09-12 23:31 ` Junio C Hamano
2016-09-08 18:21 ` [PATCH v7 06/10] pkt-line: add functions to read/write flush terminated packet streams larsxschneider
2016-09-08 21:49 ` Stefan Beller
2016-09-11 12:33 ` Lars Schneider
2016-09-11 16:03 ` Stefan Beller
2016-09-11 21:42 ` Junio C Hamano
2016-09-08 18:21 ` [PATCH v7 07/10] convert: quote filter names in error messages larsxschneider
2016-09-08 18:21 ` [PATCH v7 08/10] convert: modernize tests larsxschneider
2016-09-08 22:05 ` Stefan Beller
2016-09-11 12:34 ` Lars Schneider
2016-09-08 18:21 ` [PATCH v7 09/10] convert: make apply_filter() adhere to standard Git error handling larsxschneider
2016-09-08 18:21 ` [PATCH v7 10/10] convert: add filter.<driver>.process option larsxschneider
2016-09-10 6:29 ` Torsten Bögershausen [this message]
2016-09-12 9:49 ` Lars Schneider
2016-09-13 14:44 ` Torsten Bögershausen
2016-09-13 16:42 ` Junio C Hamano
2016-09-15 17:23 ` Lars Schneider
2016-09-15 20:04 ` Junio C Hamano
2016-09-29 6:33 ` Torsten Bögershausen
2016-09-29 9:37 ` Jakub Narębski
2016-09-10 16:40 ` Torsten Bögershausen
2016-09-13 22:04 ` Lars Schneider
2016-09-13 15:22 ` Junio C Hamano
2016-09-15 20:16 ` Lars Schneider
2016-09-15 20:24 ` Junio C Hamano
2016-09-13 16:00 ` [PATCH v7 00/10] Git filter protocol Junio C Hamano
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