Re: Surprising interaction of "binary" and "eol" gitattributes

From: Junio C Hamano <gitster@pobox.com>
Date: Mar 10, 2015, 20:01 UTC
Message-ID: <xmqq385c1v13.fsf@gitster.dls.corp.google.com>
In-Reply-To: <54FF450F.7040506@alum.mit.edu>

Michael Haggerty <mhagger@alum.mit.edu> writes:

Show 44 quoted lines

> 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
>
> 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).

The way I read the description of "eol" was that that was a more specific way to do what used to be done with "text" (meaning "OK, that may be a text file, but how exactly is the end-of-line handled?"), so I would say if the above behaved the same way as

    *.png eol=crlf text

that would be the least surprising to me. But perhaps that is only because I know which one came first and which one came later for what purpose.

But ...

> 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.

... I think this makes even more sense. I do not think the code is set up to do so. To be honest, eol_attr thing introduced in fd6cce9e (Add per-repository eol normalization, 2010-05-19) always confuses me whenever I follow this codepath.

> It also seems to me that "binary" should imply "-eol".

I thought that "eol" attribute is not even looked at when you say "binary"; that is what I recall finding out when I dug into this earlier in the thread.

http://thread.gmane.org/gmane.comp.version-control.git/264850/focus=264872