[PATCH v2] diff --shortstat --dirstat: remove duplicate output

["Mårten Kongstad" <marten.kongstad@gmail.com>]

When --shortstat is used in conjunction with --dirstat=changes, git diff will
output the dirstat information twice: first as calculated by the 'lines'
algorithm, then as calculated by the 'changes' algorithm:

    $ git diff --dirstat=changes,10 --shortstat v2.2.0..v2.2.1
     23 files changed, 453 insertions(+), 54 deletions(-)
      33.5% Documentation/RelNotes/
      26.2% t/
      46.6% Documentation/RelNotes/
      16.6% t/

The same duplication happens for --shortstat together with --dirstat=files, but
not for --shortstat together with --dirstat=lines.

Limit output to only include one dirstat part, calculated as specified
by the --dirstat parameter. Also, add test for this.

Signed-off-by: Mårten Kongstad <marten.kongstad@gmail.com>
---
Good point about hardcoded values in the tests. How about instead we check that
a specific directory appears exactly once in the output?

 diff.c                  |  2 +-
 t/t4047-diff-dirstat.sh | 11 +++++++++++
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/diff.c b/diff.c
index d1bd534..abc32c8 100644
--- a/diff.c
+++ b/diff.c
@@ -4541,7 +4541,7 @@ void diff_flush(struct diff_options *options)
 			show_stats(&diffstat, options);
 		if (output_format & DIFF_FORMAT_SHORTSTAT)
 			show_shortstats(&diffstat, options);
-		if (output_format & DIFF_FORMAT_DIRSTAT)
+		if (output_format & DIFF_FORMAT_DIRSTAT && dirstat_by_line)
 			show_dirstat_by_line(&diffstat, options);
 		free_diffstat_info(&diffstat);
 		separator++;
diff --git a/t/t4047-diff-dirstat.sh b/t/t4047-diff-dirstat.sh
index ed7e093..128f7bf 100755
--- a/t/t4047-diff-dirstat.sh
+++ b/t/t4047-diff-dirstat.sh
@@ -973,4 +973,15 @@ test_expect_success 'diff.dirstat=future_param,0,lines should warn, but still wo
 	test_i18ngrep -q "diff\\.dirstat" actual_error
 '
 
+test_expect_success '--shortstat --dirstat should output only one dirstat' '
+	git diff --shortstat --dirstat=changes HEAD^..HEAD >actual_diff_shortstat_dirstat_changes &&
+	test $(grep -c " dst/copy/changed/$" actual_diff_shortstat_dirstat_changes) = 1 &&
+
+	git diff --shortstat --dirstat=lines HEAD^..HEAD >actual_diff_shortstat_dirstat_lines &&
+	test $(grep -c " dst/copy/changed/$" actual_diff_shortstat_dirstat_lines) = 1 &&
+
+	git diff --shortstat --dirstat=files HEAD^..HEAD >actual_diff_shortstat_dirstat_files &&
+	test $(grep -c " dst/copy/changed/$" actual_diff_shortstat_dirstat_files) = 1
+'
+
 test_done
-- 
1.9.1