'git show -c' omits hunk even though file was modified from all parents

Git version 2.17.1

Commit C0 contains FileA which is empty. Both branchA and branchB point to C0.

From branchA I add the following contents to FileA (and then commit): --- One Two Three

Seven Eight Nine ---

From branchB I add the following contents to FileA (and then commit): --- One Four Three

Seven Ten Nine ---

Note: I use two newlines so that git merge sees two hunks.

Case1: 

From branchA I merge branchB and resolve the conflict as follows: --- One Two Four Three

Seven Eight Nine ---

As expected, 'git show -c' outputs the combined diff for both hunks, whereas 'git show -cc' only shows hunk1 and omits "uninteresting" hunk2.

Case2:

First I amend branchA so that the second hunk is the same as in branchB (note that the first hunk is still different between the 2 branches): --- One Two Three

Seven Ten Nine ---

Then from branchA I merge branchB and resolve the conflict as follows (keeping only the changes from branchA): --- One Two Three

Seven Ten Nine ---

I was expecting `git show -c` to output the combined diff for "uninteresting" hunk1, just as it did for hunk2 in case1. But it doesn't. I realize that this is because fileA in the merge commit's tree is identical to what it was in branchA prior to the merge (so the output of 'git show -m' only outputs the diff for one parent). But I'm wondering if this is the intended behavior.

If it's not, then the '-c' section in 'man git log' that says "it lists only files which were modified from all parents" may be a bit confusing since this requirement seems to be met.

Thanks, Ralph

So in short, one side has 1/2/3//7/10/9 in fileA and the other side has 1/4/3//7/10/9, and the result of the merge is recorded as 1/2/3//7/10/9.

Yes, that is very much intended. We do not show hunks that match one of the parents, and if there is no hunk to show, the path itself is not shown.

"We do not show hunks that match one of the parents ". But in case 1 the second hunk matches one of the parents yet `git show -c` still outputs it.

diff --combined test1 index 02ef2b0,ffc05f2..59d575d

Ralph Maalouf <ralph.maalouf@caretrx.com> writes:

The above is a single hunk (whose definition is the group of lines delimited by @@@...@@@ lines).

Ahh that clears it up for me. I incorrectly assumed that at minimum that each "<<<<<<HEAD" represented a hunk..

I searched for the definition of hunk in gitglossary but couldn't find it.

Thanks for the clarification! Ralph

-----Original Message-----
From: Junio C Hamano <gitster@pobox.com> 
Sent: Monday, July 29, 2019 5:46 PM
To: Ralph Maalouf <ralph.maalouf@caretrx.com>
Cc: 'git@vger.kernel.org' <git@vger.kernel.org>
Subject: Re: 'git show -c' omits hunk even though file was modified from all parents

Ralph Maalouf <ralph.maalouf@caretrx.com> writes:

The above is a single hunk (whose definition is the group of lines delimited by @@@...@@@ lines).