Subject: Re: combined diff, but not condensed, howto?

From: Junio C Hamano <[email-masked]>
Date: Thu, 18 Sep 2008 00:01:39 -0700

Johannes Sixt <[email-masked]> writes:

> Junio C Hamano schrieb:
> ...
>> It all happens inside combine-diff.c::make_hunks().  If you pass dense==0,
>> you should be able to get all the uninteresting hunks, I think.
>> 
>> Perhaps
>> 
>> 	$ git diff --base -c
>
> Yes, that does it!

It may do so, but I do not necessarily agree with the logic.

It is very much Ok and useful for "git diff" to default to "--cc -p", and
it may be fine for "git diff-files -p" to default to "--cc".

But I think ideally an explicit "git diff -c" and "git diff-files -c -p"
should not turn the "dense combined" mode on.

The commonality of these two functions is striking and calls for proper
refactoring, but aside from that, I think a patch like this should be
applied.  What do you think?

---

 builtin-diff-files.c |    7 ++++++-
 builtin-diff.c       |    7 ++++++-
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git i/builtin-diff-files.c w/builtin-diff-files.c
index 9bf10bb..2b578c7 100644
--- i/builtin-diff-files.c
+++ w/builtin-diff-files.c
@@ -50,7 +50,12 @@ int cmd_diff_files(int argc, const char **argv, const char *prefix)
 	    3 < rev.max_count)
 		usage(diff_files_usage);
 
-	if (rev.max_count == -1 &&
+	/*
+	 * "diff-files --base -p" should not combine merges because it
+	 * was not asked to.  "diff-files -c -p" should not densify
+	 * (the user should ask with "diff-files --cc" explicitly).
+	 */
+	if (rev.max_count == -1 && !rev.combine_merges &&
 	    (rev.diffopt.output_format & DIFF_FORMAT_PATCH))
 		rev.combine_merges = rev.dense_combined_merges = 1;
 
diff --git i/builtin-diff.c w/builtin-diff.c
index 037c303..9fb30c6 100644
--- i/builtin-diff.c
+++ w/builtin-diff.c
@@ -223,7 +223,12 @@ static int builtin_diff_files(struct rev_info *revs, int argc, const char **argv
 		argv++; argc--;
 	}
 
-	if (revs->max_count == -1 &&
+	/*
+	 * "diff --base" should not combine merges because it was not
+	 * asked to.  "diff -c" should not densify (the user should ask
+	 * with "diff --cc" explicitly.
+	 */
+	if (revs->max_count == -1 && !revs->combine_merges &&
 	    (revs->diffopt.output_format & DIFF_FORMAT_PATCH))
 		revs->combine_merges = revs->dense_combined_merges = 1;