Re: [PATCH v3 2/2] headers: include dependent headers

From: Ramsay Jones <ramsay@ramsay1.demon.co.uk>
Date: Sep 7, 2014, 21:57 UTC
Message-ID: <540CD4E4.7060600@ramsay1.demon.co.uk>
In-Reply-To: <20140907203715.GB61326@gmail.com>

On 07/09/14 21:37, David Aguilar wrote:

Show 30 quoted lines

> On Sun, Sep 07, 2014 at 12:01:00PM +0100, Ramsay Jones wrote:
>> On 07/09/14 11:35, René Scharfe wrote:
>>> Am 07.09.2014 um 11:36 schrieb David Aguilar:
>>>> Add dependent headers so that including a header does not
>>>> require including additional headers.
>>>>
>>>> This makes it so that "gcc -c $header" succeeds for each header.
>>>
>>>> diff --git a/cache.h b/cache.h
>>>> index 4d5b76c..8b827d7 100644
>>>> --- a/cache.h
>>>> +++ b/cache.h
>>>> @@ -1,7 +1,6 @@
>>>>   #ifndef CACHE_H
>>>>   #define CACHE_H
>>>>
>>>> -#include "git-compat-util.h"
>>>>   #include "strbuf.h"
>>>>   #include "hashmap.h"
>>>>   #include "advice.h"
>>>
>>> Oh, that's a new change and worth mentioning in the commit message.
>>
>> Hmm, does this not break git? Unless you also change each '.c' file which
>> includes cache.h to also include git-compat-util.h first, then I suspect
>> (if nothing else) file I/O may be broken. (see _FILE_OFFSET_BITS).
>>
>> Also, see Documentation/CodingGuidelines (lines 331-333).
> 
> This one should be okay because hashmap.h includes git-compat-util.h.

It is important that each compilation unit include 'git-compat-util.h' at the start. From the CodingGuidelines we see that 'cache.h' and 'builtin.h' are *blessed* headers which can be used instead. (I have always thought that this was a mistake; it would be much easier to just stick to using 'git-compat-util.h' at the top of each '.c' file ;-)

The fact that hashmap.h happens to include git-compat-util.h is not at all relevant here.

> 
> Jonathan will be re-rolling so I'll definitely read and test the
> patches when they're ready.  They'll probably be a more focused,
> surgical change then this version.

OK.

ATB, Ramsay Jones