Re: .gitattributes override behavior (possible bug, or documentation bug)

[Dakota Hawkins <dakota@dakotahawkins.com>]

Sorry to tack on to my previous email, but I just thought of this:

If something like "-diff=lfs" won't do what I (and git-lfs) thought it
would, do you think it would be prudent/reasonable to suggest git-lfs
add a "no-lfs" filter for exactly this case? That way I could have
explicit exclusions without any "diff=foo" shenanigans.

Thanks again,

- Dakota

On Mon, Mar 19, 2018 at 11:10 PM, Dakota Hawkins
<dakota@dakotahawkins.com> wrote:
> Thanks for the quick reply!
>
> On Mon, Mar 19, 2018 at 10:34 PM, Jeff King <peff@peff.net> wrote:
>> On Mon, Mar 19, 2018 at 09:49:28PM -0400, Dakota Hawkins wrote:
>>
>>> Summary: Trying to apply attributes to file extensions everywhere
>>> except in one directory.
>>>
>>> .gitattributes:
>>>
>>>     *.[Pp][Nn][Gg] filter=lfs diff=lfs merge=lfs -text
>>>     /.readme-docs/ -filter=lfs -diff=lfs -merge=lfs
>>>
>>> Make some data:
>>>
>>>     echo "asldkjfa;sldkjf;alsdjf" > ./.readme-docs/test.png
>>>     git add -A
>>
>> As you noted below, that second line does not match your path, because
>> attributes on a directory aren't applied recursively. And it has nothing
>> to do with overriding. If you remove the png line entirely, you can see
>> that we still do not match it. You need to use "*" to match the paths.
>
> Ah, yes, I see that. Inconsistent with .gitignore (more below), right?
>
>> You may also find that "-diff=lfs" does not do quite what you want.
>> There is no way to say "cancel any previous attribute", which I think is
>> what you're trying for here. You can only override it with a new value.
>> So:
>>
>>   /.readme-docs/* -diff
>>
>> says "do not diff this". And:
>>
>>   /.readme-docs/* diff
>>
>> says "diff this as text, even if it looks binary".
>>
>> The best you can probably do is:
>>
>>   /.readme-docs/* diff=foo
>>
>> Since you have no diff.foo.* config, that will behave in the default way
>> (including respecting the usual "is it binary" checks). So a bit hacky,
>> but I think it would work as "ignore prior diff".
>>
>> And I think filter and merge drivers should work the same.
>
> That's interesting... in this case I was taking my advice on how this
> should work from the git-lfs folks. I have promised to share what I
> find here with them, so that will help at least :)
>
> I think that makes sense to me -- there would be no good way to tell
> it what the default should have been without explicitly telling it
> what to use instead.
>
>>> Is this me misunderstanding something in the documentation? I would
>>> expect "./.readme-docs/" to match "./.readme-docs/test.png" and
>>> override the earlier "*.[Pp][Nn][Gg]" attributes.
>>>
>>> I have found the following overrides to work in lieu of the directory match:
>>>
>>>     /.readme-docs/* -filter=lfs -diff=lfs -merge=lfs
>>>     /.readme-docs/**/* -filter=lfs -diff=lfs -merge=lfs
>>>
>>> ...but I don't see a justification in the documentation for this
>>> working and the original directory filter not working.
>>
>> I could not find anything useful in gitattributes(5). There's some old
>> discussion here:
>>
>>   https://public-inbox.org/git/slrnkldd3g.1l4.jan@majutsushi.net/
>
> If I follow that correctly: There's some initial speculation that it
> would be OK to apply the attributes recursively, which is then shot
> down because it wasn't designed to be recursive (though I don't see a
> different, technical reason for that), followed by finding a (this
> same?) solution/workaround for the original problem. Is that about
> right?
>
>> which makes it clear that attributes aren't recursive, but it's probably
>> worth calling out in the documentation. In fact, I think the current
>> documentation is a bit misleading in that it says "patterns are matched
>> as in .gitignore", which is clearly not the case here.
>
> I was indeed going off of the suggestion to consult the .gitignore
> pattern matching documentation.
>
>> I think just "/.readme-docs/**" should be sufficient for your case. You
>> could also probably write "*" inside ".readme-docs/.gitattributes",
>> which may be simpler (you don't need "**" there because patterns without
>> a slash are just matched directly against the basename).
>
> Wouldn't that make the "*" inside ".readme-docs/.gitattributes",
> technically recursive when "*" matches a directory? It's always seemed
> to me that both were necessary to explicitly match things in a
> directory and its subdirectories (example, IIRC: "git ls-files --
> .gitattributes" vs "git ls-files -- .gitattributes
> **/.gitattributes"). Maybe that example is peculiar in that its a
> dotfile and can't have a wildcard before the dot?
>
> I guess my takeaway is that it would be _good_ if the gitattributes
> documentation contained the caveat about not matching directories
> recursively, but _great_ if gitattributes and gitignore (and whatever
> else there is) were consistent.
>
> At any rate, thanks for the great, quick help!
>
> -Dakota