Merge branch 'jc/fix-diff-files-unmerged' into maint

* jc/fix-diff-files-unmerged:
  diff-files: show unmerged entries correctly
  diff: remove often unused parameters from diff_unmerge()
  diff.c: return filepair from diff_unmerge()
  test: use $_z40 from test-lib

16 files changed, 120 insertions, 36 deletions

diff --git a/diff-lib.c b/diff-lib.c
index 2870de400e..3b5f2242a5 100644
--- a/diff-lib.c
+++ b/diff-lib.c
@@ -112,6 +112,8 @@ int run_diff_files(struct rev_info *revs, unsigned int option)
 
 		if (ce_stage(ce)) {
 			struct combine_diff_path *dpath;
+			struct diff_filepair *pair;
+			unsigned int wt_mode = 0;
 			int num_compare_stages = 0;
 			size_t path_len;
 
@@ -130,7 +132,7 @@ int run_diff_files(struct rev_info *revs, unsigned int option)
 
 			changed = check_removed(ce, &st);
 			if (!changed)
-				dpath->mode = ce_mode_from_stat(ce, st.st_mode);
+				wt_mode = ce_mode_from_stat(ce, st.st_mode);
 			else {
 				if (changed < 0) {
 					perror(ce->name);
@@ -138,7 +140,9 @@ int run_diff_files(struct rev_info *revs, unsigned int option)
 				}
 				if (silent_on_removed)
 					continue;
+				wt_mode = 0;
 			}
+			dpath->mode = wt_mode;
 
 			while (i < entries) {
 				struct cache_entry *nce = active_cache[i];
@@ -184,7 +188,9 @@ int run_diff_files(struct rev_info *revs, unsigned int option)
 			 * Show the diff for the 'ce' if we found the one
 			 * from the desired stage.
 			 */
-			diff_unmerge(&revs->diffopt, ce->name, 0, null_sha1);
+			pair = diff_unmerge(&revs->diffopt, ce->name);
+			if (wt_mode)
+				pair->two->mode = wt_mode;
 			if (ce_stage(ce) != diff_unmerged_stage)
 				continue;
 		}
@@ -373,8 +379,9 @@ static void do_oneway_diff(struct unpack_trees_options *o,
 	match_missing = !revs->ignore_merges;
 
 	if (cached && idx && ce_stage(idx)) {
-		diff_unmerge(&revs->diffopt, idx->name, idx->ce_mode,
-			     idx->sha1);
+		struct diff_filepair *pair;
+		pair = diff_unmerge(&revs->diffopt, idx->name);
+		fill_filespec(pair->one, idx->sha1, idx->ce_mode);
 		return;
 	}
 
diff --git a/diff.c b/diff.c
index 5376d01e1b..ba45a7df11 100644
--- a/diff.c
+++ b/diff.c
@@ -4381,20 +4381,20 @@ void diff_change(struct diff_options *options,
 		DIFF_OPT_SET(options, HAS_CHANGES);
 }
 
-void diff_unmerge(struct diff_options *options,
-		  const char *path,
-		  unsigned mode, const unsigned char *sha1)
+struct diff_filepair *diff_unmerge(struct diff_options *options, const char *path)
 {
+	struct diff_filepair *pair;
 	struct diff_filespec *one, *two;
 
 	if (options->prefix &&
 	    strncmp(path, options->prefix, options->prefix_length))
-		return;
+		return NULL;
 
 	one = alloc_filespec(path);
 	two = alloc_filespec(path);
-	fill_filespec(one, sha1, mode);
-	diff_queue(&diff_queued_diff, one, two)->is_unmerged = 1;
+	pair = diff_queue(&diff_queued_diff, one, two);
+	pair->is_unmerged = 1;
+	return pair;
 }
 
 static char *run_textconv(const char *pgm, struct diff_filespec *spec,
diff --git a/diff.h b/diff.h
index 007a0554d4..42b49d8f22 100644
--- a/diff.h
+++ b/diff.h
@@ -208,10 +208,7 @@ extern void diff_change(struct diff_options *,
 			const char *fullpath,
 			unsigned dirty_submodule1, unsigned dirty_submodule2);
 
-extern void diff_unmerge(struct diff_options *,
-			 const char *path,
-			 unsigned mode,
-			 const unsigned char *sha1);
+extern struct diff_filepair *diff_unmerge(struct diff_options *, const char *path);
 
 #define DIFF_SETUP_REVERSE      	1
 #define DIFF_SETUP_USE_CACHE		2
diff --git a/t/t1400-update-ref.sh b/t/t1400-update-ref.sh
index ff747f8229..4fd83a667a 100755
--- a/t/t1400-update-ref.sh
+++ b/t/t1400-update-ref.sh
@@ -6,7 +6,7 @@
 test_description='Test git update-ref and basic ref logging'
 . ./test-lib.sh
 
-Z=0000000000000000000000000000000000000000
+Z=$_z40
 
 test_expect_success setup '
 
diff --git a/t/t1501-worktree.sh b/t/t1501-worktree.sh
index da6252b117..63849836c8 100755
--- a/t/t1501-worktree.sh
+++ b/t/t1501-worktree.sh
@@ -7,7 +7,6 @@ test_expect_success 'setup' '
 	EMPTY_TREE=$(git write-tree) &&
 	EMPTY_BLOB=$(git hash-object -t blob --stdin </dev/null) &&
 	CHANGED_BLOB=$(echo changed | git hash-object -t blob --stdin) &&
-	ZEROES=0000000000000000000000000000000000000000 &&
 	EMPTY_BLOB7=$(echo $EMPTY_BLOB | sed "s/\(.......\).*/\1/") &&
 	CHANGED_BLOB7=$(echo $CHANGED_BLOB | sed "s/\(.......\).*/\1/") &&
 
@@ -239,10 +238,10 @@ test_expect_success '_gently() groks relative GIT_DIR & GIT_WORK_TREE' '
 
 test_expect_success 'diff-index respects work tree under .git dir' '
 	cat >diff-index-cached.expected <<-EOF &&
-	:000000 100644 $ZEROES $EMPTY_BLOB A	sub/dir/tracked
+	:000000 100644 $_z40 $EMPTY_BLOB A	sub/dir/tracked
 	EOF
 	cat >diff-index.expected <<-EOF &&
-	:000000 100644 $ZEROES $ZEROES A	sub/dir/tracked
+	:000000 100644 $_z40 $_z40 A	sub/dir/tracked
 	EOF
 
 	(
@@ -258,7 +257,7 @@ test_expect_success 'diff-index respects work tree under .git dir' '
 
 test_expect_success 'diff-files respects work tree under .git dir' '
 	cat >diff-files.expected <<-EOF &&
-	:100644 100644 $EMPTY_BLOB $ZEROES M	sub/dir/tracked
+	:100644 100644 $EMPTY_BLOB $_z40 M	sub/dir/tracked
 	EOF
 
 	(
diff --git a/t/t2011-checkout-invalid-head.sh b/t/t2011-checkout-invalid-head.sh
index 15ebdc26eb..300f8bf25c 100755
--- a/t/t2011-checkout-invalid-head.sh
+++ b/t/t2011-checkout-invalid-head.sh
@@ -15,7 +15,7 @@ test_expect_success 'checkout should not start branch from a tree' '
 '
 
 test_expect_success 'checkout master from invalid HEAD' '
-	echo 0000000000000000000000000000000000000000 >.git/HEAD &&
+	echo $_z40 >.git/HEAD &&
 	git checkout master --
 '
 
diff --git a/t/t2201-add-update-typechange.sh b/t/t2201-add-update-typechange.sh
index 2e8f702452..954fc51e5b 100755
--- a/t/t2201-add-update-typechange.sh
+++ b/t/t2201-add-update-typechange.sh
@@ -4,8 +4,6 @@ test_description='more git add -u'
 
 . ./test-lib.sh
 
-_z40=0000000000000000000000000000000000000000
-
 test_expect_success setup '
 	>xyzzy &&
 	_empty=$(git hash-object --stdin <xyzzy) &&
diff --git a/t/t3200-branch.sh b/t/t3200-branch.sh
index 286a2a6869..463ef1909f 100755
--- a/t/t3200-branch.sh
+++ b/t/t3200-branch.sh
@@ -46,7 +46,7 @@ test_expect_success \
     'git branch a/b/c && test -f .git/refs/heads/a/b/c'
 
 cat >expect <<EOF
-0000000000000000000000000000000000000000 $HEAD $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> 1117150200 +0000	branch: Created from master
+$_z40 $HEAD $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> 1117150200 +0000	branch: Created from master
 EOF
 test_expect_success \
     'git branch -l d/e/f should create a branch and a log' \
@@ -230,7 +230,7 @@ test_expect_success \
 
 # Keep this test last, as it changes the current branch
 cat >expect <<EOF
-0000000000000000000000000000000000000000 $HEAD $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> 1117150200 +0000	branch: Created from master
+$_z40 $HEAD $GIT_COMMITTER_NAME <$GIT_COMMITTER_EMAIL> 1117150200 +0000	branch: Created from master
 EOF
 test_expect_success \
     'git checkout -b g/h/i -l should create a branch and a log' \
diff --git a/t/t3600-rm.sh b/t/t3600-rm.sh
index cd093bd347..9fd28bcf34 100755
--- a/t/t3600-rm.sh
+++ b/t/t3600-rm.sh
@@ -240,11 +240,10 @@ test_expect_success 'refresh index before checking if it is up-to-date' '
 
 test_expect_success 'choking "git rm" should not let it die with cruft' '
 	git reset -q --hard &&
-	H=0000000000000000000000000000000000000000 &&
 	i=0 &&
 	while test $i -lt 12000
 	do
-	    echo "100644 $H 0	some-file-$i"
+	    echo "100644 $_z40 0	some-file-$i"
 	    i=$(( $i + 1 ))
 	done | git update-index --index-info &&
 	git rm -n "some-file-*" | :;
diff --git a/t/t4002-diff-basic.sh b/t/t4002-diff-basic.sh
index 9fb8ca06a8..a5e8b83083 100755
--- a/t/t4002-diff-basic.sh
+++ b/t/t4002-diff-basic.sh
@@ -126,15 +126,12 @@ cat >.test-recursive-AB <<\EOF
 :100644 100644 3fdbe17fd013303a2e981e1ca1c6cd6e72789087 7e09d6a3a14bd630913e8c75693cea32157b606d M	Z/NM
 EOF
 
-x40='[0-9a-f][0-9a-f][0-9a-f][0-9a-f][0-9a-f]'
-x40="$x40$x40$x40$x40$x40$x40$x40$x40"
-z40='0000000000000000000000000000000000000000'
 cmp_diff_files_output () {
     # diff-files never reports additions.  Also it does not fill in the
     # object ID for the changed files because it wants you to look at the
     # filesystem.
     sed <"$2" >.test-tmp \
-	-e '/^:000000 /d;s/'$x40'\( [MCRNDU][0-9]*\)	/'$z40'\1	/' &&
+	-e '/^:000000 /d;s/'$_x40'\( [MCRNDU][0-9]*\)	/'$_z40'\1	/' &&
     test_cmp "$1" .test-tmp
 }
 
diff --git a/t/t4020-diff-external.sh b/t/t4020-diff-external.sh
index a7602cf923..083f62d1d6 100755
--- a/t/t4020-diff-external.sh
+++ b/t/t4020-diff-external.sh
@@ -4,8 +4,6 @@ test_description='external diff interface test'
 
 . ./test-lib.sh
 
-_z40=0000000000000000000000000000000000000000
-
 test_expect_success setup '
 
 	test_tick &&
diff --git a/t/t4027-diff-submodule.sh b/t/t4027-diff-submodule.sh
index 241a74d2a2..518bf9524e 100755
--- a/t/t4027-diff-submodule.sh
+++ b/t/t4027-diff-submodule.sh
@@ -5,7 +5,6 @@ test_description='difference in submodules'
 . ./test-lib.sh
 . "$TEST_DIRECTORY"/diff-lib.sh
 
-_z40=0000000000000000000000000000000000000000
 test_expect_success setup '
 	test_tick &&
 	test_create_repo sub &&
diff --git a/t/t4046-diff-unmerged.sh b/t/t4046-diff-unmerged.sh
new file mode 100755
index 0000000000..25d50a654a
--- /dev/null
+++ b/t/t4046-diff-unmerged.sh
@@ -0,0 +1,87 @@
+#!/bin/sh
+
+test_description='diff with unmerged index entries'
+. ./test-lib.sh
+
+test_expect_success setup '
+	for i in 0 1 2 3
+	do
+		blob=$(echo $i | git hash-object --stdin) &&
+		eval "blob$i=$blob" &&
+		eval "m$i=\"100644 \$blob$i $i\"" || break
+	done &&
+	paths= &&
+	for b in o x
+	do
+		for o in o x
+		do
+			for t in o x
+			do
+				path="$b$o$t" &&
+				case "$path" in ooo) continue ;; esac
+				paths="$paths$path " &&
+				p="	$path" &&
+				case "$b" in x) echo "$m1$p" ;; esac &&
+				case "$o" in x) echo "$m2$p" ;; esac &&
+				case "$t" in x) echo "$m3$p" ;; esac ||
+				break
+			done || break
+		done || break
+	done >ls-files-s.expect &&
+	git update-index --index-info <ls-files-s.expect &&
+	git ls-files -s >ls-files-s.actual &&
+	test_cmp ls-files-s.expect ls-files-s.actual
+'
+
+test_expect_success 'diff-files -0' '
+	for path in $paths
+	do
+		>"$path" &&
+		echo ":000000 100644 $_z40 $_z40 U	$path"
+	done >diff-files-0.expect &&
+	git diff-files -0 >diff-files-0.actual &&
+	test_cmp diff-files-0.expect diff-files-0.actual
+'
+
+test_expect_success 'diff-files -1' '
+	for path in $paths
+	do
+		>"$path" &&
+		echo ":000000 100644 $_z40 $_z40 U	$path" &&
+		case "$path" in
+		x??) echo ":100644 100644 $blob1 $_z40 M	$path"
+		esac
+	done >diff-files-1.expect &&
+	git diff-files -1 >diff-files-1.actual &&
+	test_cmp diff-files-1.expect diff-files-1.actual
+'
+
+test_expect_success 'diff-files -2' '
+	for path in $paths
+	do
+		>"$path" &&
+		echo ":000000 100644 $_z40 $_z40 U	$path" &&
+		case "$path" in
+		?x?) echo ":100644 100644 $blob2 $_z40 M	$path"
+		esac
+	done >diff-files-2.expect &&
+	git diff-files -2 >diff-files-2.actual &&
+	test_cmp diff-files-2.expect diff-files-2.actual &&
+	git diff-files >diff-files-default-2.actual &&
+	test_cmp diff-files-2.expect diff-files-default-2.actual
+'
+
+test_expect_success 'diff-files -3' '
+	for path in $paths
+	do
+		>"$path" &&
+		echo ":000000 100644 $_z40 $_z40 U	$path" &&
+		case "$path" in
+		??x) echo ":100644 100644 $blob3 $_z40 M	$path"
+		esac
+	done >diff-files-3.expect &&
+	git diff-files -3 >diff-files-3.actual &&
+	test_cmp diff-files-3.expect diff-files-3.actual
+'
+
+test_done
diff --git a/t/t7011-skip-worktree-reading.sh b/t/t7011-skip-worktree-reading.sh
index bb4066f767..8f3b54d826 100755
--- a/t/t7011-skip-worktree-reading.sh
+++ b/t/t7011-skip-worktree-reading.sh
@@ -24,7 +24,7 @@ H sub/2
 EOF
 
 NULL_SHA1=e69de29bb2d1d6434b8b29ae775ad8c2e48c5391
-ZERO_SHA0=0000000000000000000000000000000000000000
+
 setup_absent() {
 	test -f 1 && rm 1
 	git update-index --remove 1 &&
@@ -120,7 +120,7 @@ test_expect_success 'grep with skip-worktree file' '
 	test "$(git grep --no-ext-grep test)" = "1:test"
 '
 
-echo ":000000 100644 $ZERO_SHA0 $NULL_SHA1 A	1" > expected
+echo ":000000 100644 $_z40 $NULL_SHA1 A	1" > expected
 test_expect_success 'diff-index does not examine skip-worktree absent entries' '
 	setup_absent &&
 	git diff-index HEAD -- 1 > result &&
diff --git a/t/t7012-skip-worktree-writing.sh b/t/t7012-skip-worktree-writing.sh
index 14fcb1c7f5..c4104009e1 100755
--- a/t/t7012-skip-worktree-writing.sh
+++ b/t/t7012-skip-worktree-writing.sh
@@ -54,7 +54,7 @@ test_expect_success 'read-tree removes worktree, dirty case' '
 '
 
 NULL_SHA1=e69de29bb2d1d6434b8b29ae775ad8c2e48c5391
-ZERO_SHA0=0000000000000000000000000000000000000000
+
 setup_absent() {
 	test -f 1 && rm 1
 	git update-index --remove 1 &&
diff --git a/t/test-lib.sh b/t/test-lib.sh
index abc47f3abc..8a274fbe79 100644
--- a/t/test-lib.sh
+++ b/t/test-lib.sh
@@ -89,6 +89,9 @@ esac
 _x05='[0-9a-f][0-9a-f][0-9a-f][0-9a-f][0-9a-f]'
 _x40="$_x05$_x05$_x05$_x05$_x05$_x05$_x05$_x05"
 
+# Zero SHA-1
+_z40=0000000000000000000000000000000000000000
+
 # Each test should start with something like this, after copyright notices:
 #
 # test_description='Description of this test...