Re: Lines missing from git diff-tree -p -c output?

From: Matthijs Kooijman <matthijs@stdin.nl>
Date: May 15, 2013, 15:46 UTC
Message-ID: <20130515154638.GQ25742@login.drsnuggles.stderr.nl>
In-Reply-To: <20130515143508.GO25742@login.drsnuggles.stderr.nl>

Hi folks,

Show 14 quoted lines

> $ git diff-tree -p -c HEAD
> d945a51b6ca22e6e8e550c53980d026f11b05158
> diff --combined file
> index 3404f54,0eab113..e8c8c18
> --- a/file
> +++ b/file
> @@@ -1,7 -1,5 +1,6 @@@
>  +LEFT
>   BASE2
>   BASE3
>   BASE4
> - BASE5
> + BASE5MODIFIED
>   BASE6

I found the spot in the code where this is going wrong, there is an incorrectly set "no_pre_delete" flag for the context lines before each hunk. Since a patch says more than a thousand words, here's what I think will fix this problem:

diff --git a/combine-diff.c b/combine-diff.c
index 77d7872..d36bfcf 100644
--- a/combine-diff.c
+++ b/combine-diff.c
@@ -518,8 +518,11 @@ static int give_context(struct sline *sline, unsigned long cnt, int num_parent)
                unsigned long k;
 
                /* Paint a few lines before the first interesting line. */
-               while (j < i)
-                       sline[j++].flag |= mark | no_pre_delete;
+               while (j < i) {
+                       if (!(sline[j++].flag & mark))
+                               sline[j++].flag |= no_pre_delete;
+                       sline[j++].flag |= mark;
+               }
 
        again:
                /* we know up to i is to be included.  where does the

I'll see if I can write up a testcase and then submit this as a proper
patch, but I wanted to at least send this over now lest someone wastes
time coming to the same conclusion as I did.

Gr.

Matthijs