Merge branch 'ks/combine-diff'

Teach combine-diff to honour the path-output-order imposed by
diffcore-order, and optimize how matching paths are found in
the N-way diffs made with parents.

* ks/combine-diff:
  tests: add checking that combine-diff emits only correct paths
  combine-diff: simplify intersect_paths() further
  combine-diff: combine_diff_path.len is not needed anymore
  combine-diff: optimize combine_diff_path sets intersection
  diff test: add tests for combine-diff with orderfile
  diffcore-order: export generic ordering interface

2 files changed, 127 insertions, 0 deletions

diff --git a/t/t4056-diff-order.sh b/t/t4056-diff-order.sh
index 9e2b29ede5..c0460bb0e5 100755
--- a/t/t4056-diff-order.sh
+++ b/t/t4056-diff-order.sh
@@ -97,4 +97,25 @@ do
 	'
 done
 
+test_expect_success 'setup for testing combine-diff order' '
+	git checkout -b tmp HEAD~ &&
+	create_files 3 &&
+	git checkout master &&
+	git merge --no-commit -s ours tmp &&
+	create_files 5
+'
+
+test_expect_success "combine-diff: no order (=tree object order)" '
+	git diff --name-only HEAD HEAD^ HEAD^2 >actual &&
+	test_cmp expect_none actual
+'
+
+for i in 1 2
+do
+	test_expect_success "combine-diff: orderfile using option ($i)" '
+		git diff -Oorder_file_$i --name-only HEAD HEAD^ HEAD^2 >actual &&
+		test_cmp expect_$i actual
+	'
+done
+
 test_done
diff --git a/t/t4057-diff-combined-paths.sh b/t/t4057-diff-combined-paths.sh
new file mode 100755
index 0000000000..097e63215e
--- /dev/null
+++ b/t/t4057-diff-combined-paths.sh
@@ -0,0 +1,106 @@
+#!/bin/sh
+
+test_description='combined diff show only paths that are different to all parents'
+
+. ./test-lib.sh
+
+# verify that diffc.expect matches output of
+# `git diff -c --name-only HEAD HEAD^ HEAD^2`
+diffc_verify () {
+	git diff -c --name-only HEAD HEAD^ HEAD^2 >diffc.actual &&
+	test_cmp diffc.expect diffc.actual
+}
+
+test_expect_success 'trivial merge - combine-diff empty' '
+	for i in $(test_seq 1 9)
+	do
+		echo $i >$i.txt	&&
+		git add $i.txt
+	done &&
+	git commit -m "init" &&
+	git checkout -b side &&
+	for i in $(test_seq 2 9)
+	do
+		echo $i/2 >>$i.txt
+	done &&
+	git commit -a -m "side 2-9" &&
+	git checkout master &&
+	echo 1/2 >1.txt &&
+	git commit -a -m "master 1" &&
+	git merge side &&
+	>diffc.expect &&
+	diffc_verify
+'
+
+
+test_expect_success 'only one trully conflicting path' '
+	git checkout side &&
+	for i in $(test_seq 2 9)
+	do
+		echo $i/3 >>$i.txt
+	done &&
+	echo "4side" >>4.txt &&
+	git commit -a -m "side 2-9 +4" &&
+	git checkout master &&
+	for i in $(test_seq 1 9)
+	do
+		echo $i/3 >>$i.txt
+	done &&
+	echo "4master" >>4.txt &&
+	git commit -a -m "master 1-9 +4" &&
+	test_must_fail git merge side &&
+	cat <<-\EOF >4.txt &&
+	4
+	4/2
+	4/3
+	4master
+	4side
+	EOF
+	git add 4.txt &&
+	git commit -m "merge side (2)" &&
+	echo 4.txt >diffc.expect &&
+	diffc_verify
+'
+
+test_expect_success 'merge introduces new file' '
+	git checkout side &&
+	for i in $(test_seq 5 9)
+	do
+		echo $i/4 >>$i.txt
+	done &&
+	git commit -a -m "side 5-9" &&
+	git checkout master &&
+	for i in $(test_seq 1 3)
+	do
+		echo $i/4 >>$i.txt
+	done &&
+	git commit -a -m "master 1-3 +4hello" &&
+	git merge side &&
+	echo "Hello World" >4hello.txt &&
+	git add 4hello.txt &&
+	git commit --amend &&
+	echo 4hello.txt >diffc.expect &&
+	diffc_verify
+'
+
+test_expect_success 'merge removed a file' '
+	git checkout side &&
+	for i in $(test_seq 5 9)
+	do
+		echo $i/5 >>$i.txt
+	done &&
+	git commit -a -m "side 5-9" &&
+	git checkout master &&
+	for i in $(test_seq 1 3)
+	do
+		echo $i/4 >>$i.txt
+	done &&
+	git commit -a -m "master 1-3" &&
+	git merge side &&
+	git rm 4.txt &&
+	git commit --amend &&
+	echo 4.txt >diffc.expect &&
+	diffc_verify
+'
+
+test_done