Fix "git log --diff-filter" bug

In commit b7bb760d5ed4881422673d32f869d140221d3564 (Fix revision
log diff setup, avoid unnecessary diff generation) an optimization was
made to avoid unnecessary diff generation.  This was partly fixed in
99516e35d096f41e7133cacde8fbed8ee9a3ecd0 (Fix embarrassing "git log
--follow" bug).  The '--diff-filter' option also needs the diff machinery
in action.

Signed-off-by: Arjen Laarhoven <arjen@yaph.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

2 files changed, 78 insertions, 2 deletions

diff --git a/revision.c b/revision.c
index 7e2f4f1eb..6e85aaa3f 100644
--- a/revision.c
+++ b/revision.c
@@ -1290,8 +1290,10 @@ int setup_revisions(int argc, const char **argv, struct rev_info *revs, const ch
 	if (revs->diffopt.output_format & ~DIFF_FORMAT_NO_OUTPUT)
 		revs->diff = 1;
 
-	/* Pickaxe and rename following needs diffs */
-	if (revs->diffopt.pickaxe || DIFF_OPT_TST(&revs->diffopt, FOLLOW_RENAMES))
+	/* Pickaxe, diff-filter and rename following need diffs */
+	if (revs->diffopt.pickaxe ||
+	    revs->diffopt.filter ||
+	    DIFF_OPT_TST(&revs->diffopt, FOLLOW_RENAMES))
 		revs->diff = 1;
 
 	if (revs->topo_order)
diff --git a/t/t4202-log.sh b/t/t4202-log.sh
new file mode 100755
index 000000000..b53645417
--- /dev/null
+++ b/t/t4202-log.sh
@@ -0,0 +1,74 @@
+#!/bin/sh
+
+test_description='git log'
+
+. ./test-lib.sh
+
+test_expect_success setup '
+
+	echo one >one &&
+	git add one &&
+	test_tick &&
+	git commit -m initial &&
+
+	echo ichi >one &&
+	git add one &&
+	test_tick &&
+	git commit -m second &&
+
+	mkdir a &&
+	echo ni >a/two &&
+	git add a/two &&
+	test_tick &&
+	git commit -m third &&
+
+	echo san >a/three &&
+	git add a/three &&
+	test_tick &&
+	git commit -m fourth &&
+
+	git rm a/three &&
+	test_tick &&
+	git commit -m fifth
+
+'
+
+test_expect_success 'diff-filter=A' '
+
+	actual=$(git log --pretty="format:%s" --diff-filter=A HEAD) &&
+	expect=$(echo fourth ; echo third ; echo initial) &&
+	test "$actual" = "$expect" || {
+		echo Oops
+		echo "Actual: $actual"
+		false
+	}
+
+'
+
+test_expect_success 'diff-filter=M' '
+
+	actual=$(git log --pretty="format:%s" --diff-filter=M HEAD) &&
+	expect=$(echo second) &&
+	test "$actual" = "$expect" || {
+		echo Oops
+		echo "Actual: $actual"
+		false
+	}
+
+'
+
+test_expect_success 'diff-filter=D' '
+
+	actual=$(git log --pretty="format:%s" --diff-filter=D HEAD) &&
+	expect=$(echo fifth) &&
+	test "$actual" = "$expect" || {
+		echo Oops
+		echo "Actual: $actual"
+		false
+	}
+
+'
+
+
+
+test_done
\ No newline at end of file