From: Peter Valdemar Mørch (Lists) <4ux6as402@sneakemail.com>
Date: Thu, 24 Jul 2008 09:41:42 GMT
Subject: Re: [PATCH] Document disabling core.whitespace values trailing-space and space-before-tab
Message-ID: <48884E56.6070801@sneakemail.com>
In-Reply-To: <20080724172912.6117@nanako3.lavabit.com>

Actually, it gets stranger and stranger!

Nanako Shiraishi nanako3-at-lavabit.com |Lists| wrote:
>> The '-trailing-space' syntax to disable the trailing-space setting 
>> is not obvious and not documented as far as I can see. I would have
>> assumed a value of '' would disable it.
> 
> Doesn't gitattributes(5) describe the overall syntax in detail?

First, git-config.1 does not mention gitattributes except for specific
settings. core.whitespace is not one of these.

gitattributes.5 has:
> Sometimes you would need to override an setting of an attribute for a
>  path to unspecified state. This can be done by listing the name of 
> the attribute prefixed with an exclamation point !.

note that this is ! before the *name* of the attribute, and for 
"Checking whitespace errors / whitespace":

> The core.whitespace configuration variable allows you to define what 
> diff and apply should consider whitespace errors for all paths in the
>  project (See git-config(1)). This attribute gives you finer control 
> per path.
...
> Unspecified: Use the value of core.whitespace configuration variable
>  to decide what to notice as error.
> 
> String: Specify a comma separate list of common whitespace problems 
> to notice in the same format as core.whitespace configuration 
> variable.

So now, git attributes says to unspecify a setting with '!' in front of
the attribute *name*, which for core.whitespace means use the value from
git-config, which if not specified means to error on e.g. trailing-space.

Now, I notice that git's own .gitattributes has this:
> * whitespace=!indent,trail,space
> *.[ch] whitespace

Which I assume actually works, but is invalid according to git-config.1 
and gitattributes.5 because:

For the first line, neither of the values 'indent', 'trail' nor 'space'
are valid for core.whitespace, and the '!' notation is not defined in
neither gitattributes.5 nor in git-config.1 for *values*.

For the second line, gitattributes states generally about attributes that:
> Set: The path has the attribute with special value "true"; this is 
> specified by listing only the name of the attribute in the attribute 
> list.

A value of true (unspecified would have required:"*.[ch] !whitespace") 
is not valid for core.whitespace either.

So now (as I read it), neither git-config.1 nor gitattributes.5 specify 
how to turn off core.whitespace "elements", but .gitattributes (from git 
itself) uses one notation (!) with settings that are invalid for other 
reaons, while "grep core.whitespace t/*" uses another notation (-) to 
turn off elements.

Also in t/* the elements have various different names, such as: "trail", 
"trailing", "trailing-space". t/t4019-diff-wserror.sh also uses this:
> echo "F whitespace=-trail" >.gitattributes
just to make things interesting!

It seems that there is some inconsistency about this. Perhaps 
documentation (and changing t/* and .gitattributes accordingly) isn't 
such a bad idea! :D

Peter
-- 
Peter Valdemar Mørch
http://www.morch.com