From: "Torsten Bögershausen" <tboegi@web.de>
To: "Michael Haggerty" <mhagger@alum.mit.edu>,
"Torsten Bögershausen" <tboegi@web.de>,
"Junio C Hamano" <gitster@pobox.com>
Cc: git discussion list <git@vger.kernel.org>
Subject: Re: Surprising interaction of "binary" and "eol" gitattributes
Date: Tue, 10 Mar 2015 21:26:30 +0100 [thread overview]
Message-ID: <54FF5376.7070500@web.de> (raw)
In-Reply-To: <54FF450F.7040506@alum.mit.edu>
On 10.03.15 20:25, Michael Haggerty wrote:
> On 03/06/2015 10:30 PM, Torsten Bögershausen wrote:
>>
>>> Oops, I misunderstood an internal bug report. In seems that it is the
>>> following scenario that is incorrect:
>>>
>>> *.png text=auto eol=crlf
>> Hm, I don't know if we support this combination at all.
>
> The user can specify this combination in a .gitattributes file and we
> have to react to it *some way*. Theoretically we could document that
> this combination is undefined and/or emit an error if we see this
> combination, but we don't do so.
>
>> The current logic supports auto-detection of text/binary,
>> * text=auto
>> (the files will get the line ending from core.eol or core.autocrlf)
>>
>> or the the setting of a line ending:
>> *.sh eol=lf
>> *.bat eol=crlf
>>
>>
>> Is there a special use-case, which needs the combination of both ?
>
> I'm still trying to infer the spirit of the current behavior, so caveats
> here.
>
> This comes from a real-life scenario where a user, somewhere early in
> .gitattributes, had
>
> * text
> * eol=crlf
>
> and then later (this could be in a subdirectory) tried to carve out
> exceptions to this rule by using
>
> *.png binary
> * text=auto
Hm,
I can see 2 problems here:
the "binary" attribute does not exist at all.
I sometimes which we had it, but we don't.
There is "text" and "-text", and that is it.
The other problem is the order of the lines, which is fully
intuitive for each person who has ever written a "matching parser".
The parser matches each file namr on it's own, depending on the matching:
*.png -text
* text=auto
means that all png files are binary, and ALL files are "auto".
Guess what happens to the png's ?
The second rule wins, as it is the last rule processed.
git check-attr text *
A.png: text: auto
B.txt: text: auto
---
If we reverse the order in .gitattributes, things look better:
* text=auto
*.png -text
git check-attr text *
A.png: text: unset
B.txt: text: auto
--------------------
This is not very intuitive or even surprising, at least for many people.
Unless I mis-understand the problem, it may be that the documentation may be updated ?
The general rule for writing .gitattributes
is to specify the "wider" rules first, and then the more specific rules after that.
It could be that
Documentation/gitattributes.txt
should mention this instead:
------------------------
* -text
*.txt text
*.vcproj eol=crlf
*.sh eol=lf
------------------------
The other thing is to promote/mention the command
"git check-attr text *"
at a prominent place.
> Intuitively it *feels* like either of the later lines should suppress
> EOL translation in PNG files (assuming the PNG file has a NUL byte in
> the first 8k, which this one did).
>
> It seems to me that setting "text=auto" should mean that Git uses its
> heuristic to guess whether a particular file is text or not, and then
> treats the file as if it had "text" or "-text" set. If the latter, then
> EOL translation should be suppressed.
>
> It also seems to me that "binary" should imply "-eol".
>
> Michael
>
next prev parent reply other threads:[~2015-03-10 20:26 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-05 16:38 Surprising interaction of "binary" and "eol" gitattributes Michael Haggerty
2015-03-05 20:49 ` Torsten Bögershausen
2015-03-05 22:08 ` Junio C Hamano
2015-03-06 5:59 ` Torsten Bögershausen
2015-03-06 17:51 ` Michael Haggerty
2015-03-06 21:30 ` Torsten Bögershausen
2015-03-10 19:25 ` Michael Haggerty
2015-03-10 20:01 ` Junio C Hamano
2015-03-10 22:16 ` Michael Haggerty
2015-03-10 22:54 ` Junio C Hamano
2015-03-11 5:54 ` Torsten Bögershausen
2015-03-11 17:59 ` Junio C Hamano
2015-03-11 20:30 ` Johannes Sixt
2015-03-11 21:31 ` Junio C Hamano
2015-03-11 21:43 ` Junio C Hamano
2015-03-10 20:26 ` Torsten Bögershausen [this message]
2015-03-10 22:24 ` Michael Haggerty
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