Re: [PATCH] new test fails "add -p" for adds on the top line

Nanako Shiraishi wrote:

Quoting Matt Graham [off-list ref]:

quoted

add -p doesn't work for some diffs.  diffs adding a new line at the top of
the file with other adds later in the file are one way to trigger the problem.

during add -p, split the diff and then answer y for all segments.  the file
won't have been added to the index.

Signed-off-by: Matthew Graham <redacted>

I tried "git-add -p" from different versions and I found out that versions before the commit 0beee4c6dec15292415e3d56075c16a76a22af54 doesn't have this problem.

commit 0beee4c6dec15292415e3d56075c16a76a22af54
Author: Thomas Rast [off-list ref]
Date:   Wed Jul 2 23:59:44 2008 +0200

    git-add--interactive: remove hunk coalescing
    
    Current git-apply has no trouble at all applying chunks that have
    overlapping context, as produced by the splitting feature. So we can
    drop the manual coalescing.
    
    Signed-off-by: Thomas Rast [off-list ref]
    Signed-off-by: Junio C Hamano [off-list ref]

The above commit still reverts cleanly, but AFAICS merge_hunk blindly
trusts the hunk headers, an assumption that is no longer valid due to
the 'edit' feature.  So either we need to recount the hunk headers
prior to merging (which was rejected back in the 'edit' feature
discussion due to code complexity) or find some other solution.

Passing either --unidiff-zero or -C1 with the failing patch fixes the
problem, but oddly (to me at least) -C2 does not.  The generated error
looks like

  $ git apply --check -v -C2 < patch
  Checking patch file...
  error: while searching for:
  baseline
  content

  error: patch failed: file:1
  error: file: patch does not apply

The corresponding call (builtin-apply.c:2093) is

			error("while searching for:\n%.*s",
			      (int)(old - oldlines), oldlines);

so it does not seem to insert the extra newline.  Is it actually
looking for a blank line in the context?  If so, wouldn't that be a
git-apply bug?

-- 
Thomas Rast
trast@{inf,student}.ethz.ch