Re: [PATCH] test: add git apply whitespace expansion tests

> "Kyle J. McKay" <mackyle@gmail.com> writes:
>
>> On Jan 21, 2015, at 14:33, Junio C Hamano wrote:
>>
>>> "Kyle J. McKay" <mackyle@gmail.com> writes:
>>>
>>>> So since I've not been able to get test 2 or 3 to core dump (even
>>>> before 250b3c6c) I tend to believe you are correct in that the code
>>>> thinks (incorrectly) that the result should fit within the buffer.
>>>
>>> Thanks; let me steal your tests when I reroll.
>>
>> Awesome. :)
>>
>> But please squash in this tiny change if using the tests verbatim:
>
> Thanks.  I actually have a question wrt the need for $MAKE_PATCHES.
>
> It would have been more natural to do something like:
>
> test_expect_success 'setup' '
> 	printf "\t%s\n" 1 2 3 4 5 6 >before &&
> 	printf "\t%s\n" 1 2 3 >after &&
> 	printf "%64s\n" a b c >>after &&
> 	printf "\t%s\n" 4 5 6 >>after &&
> 	git diff --no-index before after |
> 	sed -e "s/before/test-1/" -e "s/after/test-1/" >patch1.patch &&
> 	printf "%64s\n" 1 2 3 4 5 6 >test-1 &&
> 	printf "%64s\n" 1 2 3 a b c 4 5 6 >expect-1 &&
>
> 	printf "\t%s\n" a b c d e f >before &&
> 	printf "\t%s\n" a b c >after &&
>        ...
> 	cat test-4 >expect-4 &&
> 	printf "%64s\n" a b c >>expect-4 &&
> 	while test $x -lt 100
> 	do
> 		printf "%63s%02d\n" "" $x >>test-4
> 		printf "%63s%02d\n" "" $x >>expect-4
> 		x=$(( $x + 1 ))
> 	done &&
>
> 	git config core.whitespace tab-in-indent,tabwidth=63 &&
>        git config apply.whitespace fix
> '
>
> test_expect_success 'apply with ws expansion (1)' '
> 	git apply patch1.patch &&
>        test_cmp test-1 expect-1
> '
>
> and if you want test files you can just skip tests #2 and later,
> without introducing an ad-hoc mechanism like you did.
>
> Was there something more than that that you wanted from
> $MAKE_PATCHES?

> In any case, here is an update to that sanity check patch to catch
> the two cases the BUG did not trigger.
>
> Sometimes the caller under-counted the size of the result but
> thought that it would still fit within the original (hence allowing
> us to update in-place by passing postlen==0) but the actual result
> was larger than the space we have allocated in the postimage,
> clobbering the piece of memory after the postimage->buf.
>
>
> diff --git a/builtin/apply.c b/builtin/apply.c
> index 31f8733..3b7ba63 100644
> --- a/builtin/apply.c
> +++ b/builtin/apply.c
> @@ -2171,6 +2171,12 @@ static void update_pre_post_images(struct  
> image *preimage,
> 		ctx++;
> 	}
>
> +	if (postlen
> +	    ? postlen < new - postimage->buf
> +	    : postimage->len < new - postimage->buf)
> +		die("BUG: caller miscounted postlen: asked %d, orig = %d, used =  
> %d",
> +		    (int)postlen, (int) postimage->len, (int)(new - postimage- 
> >buf));
> +
> 	/* Fix the length of the whole thing */
> 	postimage->len = new - postimage->buf;
> 	postimage->nr -= reduced;