Re: [PATCH] t4067: make rename detection test output raw diff

[Derrick Stolee <stolee@gmail.com>]

On 5/19/2020 2:31 PM, Jonathan Tan wrote:
> 95acf11a3d ("diff: restrict when prefetching occurs", 2020-04-07) taught
> diff to prefetch blobs in a more limited set of situations. These
> limited situations include when the output format requires blob data,
> and when inexact rename detection is needed.
> 
> There is an existing test case that tests inexact rename detection, but
> it also uses an output format that requires blob data, resulting in the
> inexact-rename-detection-only code not being tested. Update this test to
> use the raw output format, which does not require blob data.
> 
> Thanks to Derrick Stolee for noticing this lapse in code coverage and
> for doing the preliminary analysis [1].
> 
> [1] https://lore.kernel.org/git/853759d3-97c3-241f-98e1-990883cd204e@gmail.com/
> 
> Signed-off-by: Jonathan Tan <jonathantanmy@google.com>
> ---
> Thanks, Stolee. Yes, we were never in a situation where there are any
> missing objects at the point of inexact rename detection (despite having
> a test exactly for this), but this situation is possible, and I've
> updated the test so that we encounter this situation.

Thanks for finding the test bug!

> ---
>  t/t4067-diff-partial-clone.sh | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/t/t4067-diff-partial-clone.sh b/t/t4067-diff-partial-clone.sh
> index c1ed1c2fc4..ef8e0e9cb0 100755
> --- a/t/t4067-diff-partial-clone.sh
> +++ b/t/t4067-diff-partial-clone.sh
> @@ -125,8 +125,8 @@ test_expect_success 'diff with rename detection batches blobs' '
>  
>  	# Ensure that there is exactly 1 negotiation by checking that there is
>  	# only 1 "done" line sent. ("done" marks the end of negotiation.)
> -	GIT_TRACE_PACKET="$(pwd)/trace" git -C client diff -M HEAD^ HEAD >out &&
> -	grep "similarity index" out &&
> +	GIT_TRACE_PACKET="$(pwd)/trace" git -C client diff --raw -M HEAD^ HEAD >out &&
> +	grep ":100644 100644.*R[0-9][0-9][0-9].*b.*c" out &&

--raw definitely does rename detection and I understand the need
to adjust your grep command here.

Thanks,
-Stolee