Merge branch 'ar/diff'

* ar/diff:
  Add tests for --quiet option of diff programs
  try-to-simplify-commit: use diff-tree --quiet machinery.
  revision.c: explain what tree_difference does
  Teach --quiet to diff backends.
  diff --quiet
  Remove unused diffcore_std_no_resolve
  Allow git-diff exit with codes similar to diff(1)

2 files changed, 159 insertions, 0 deletions

diff --git a/t/t4017-diff-retval.sh b/t/t4017-diff-retval.sh
new file mode 100755
index 000000000..68731908b
--- /dev/null
+++ b/t/t4017-diff-retval.sh
@@ -0,0 +1,79 @@
+#!/bin/sh
+
+test_description='Return value of diffs'
+
+. ./test-lib.sh
+
+test_expect_success 'setup' '
+	echo 1 >a &&
+	git add . &&
+	git commit -m first &&
+	echo 2 >b &&
+	git add . &&
+	git commit -a -m second
+'
+
+test_expect_success 'git diff-tree HEAD^ HEAD' '
+	git diff-tree --exit-code HEAD^ HEAD
+	test $? = 1
+'
+test_expect_success 'git diff-tree HEAD^ HEAD -- a' '
+	git diff-tree --exit-code HEAD^ HEAD -- a
+	test $? = 0
+'
+test_expect_success 'git diff-tree HEAD^ HEAD -- b' '
+	git diff-tree --exit-code HEAD^ HEAD -- b
+	test $? = 1
+'
+test_expect_success 'echo HEAD | git diff-tree --stdin' '
+	echo $(git rev-parse HEAD) | git diff-tree --exit-code --stdin
+	test $? = 1
+'
+test_expect_success 'git diff-tree HEAD HEAD' '
+	git diff-tree --exit-code HEAD HEAD
+	test $? = 0
+'
+test_expect_success 'git diff-files' '
+	git diff-files --exit-code
+	test $? = 0
+'
+test_expect_success 'git diff-index --cached HEAD' '
+	git diff-index --exit-code --cached HEAD
+	test $? = 0
+'
+test_expect_success 'git diff-index --cached HEAD^' '
+	git diff-index --exit-code --cached HEAD^
+	test $? = 1
+'
+test_expect_success 'git diff-index --cached HEAD^' '
+	echo text >>b &&
+	echo 3 >c &&
+	git add . && {
+		git diff-index --exit-code --cached HEAD^
+		test $? = 1
+	}
+'
+test_expect_success 'git diff-tree -Stext HEAD^ HEAD -- b' '
+	git commit -m "text in b" && {
+		git diff-tree -p --exit-code -Stext HEAD^ HEAD -- b
+		test $? = 1
+	}
+'
+test_expect_success 'git diff-tree -Snot-found HEAD^ HEAD -- b' '
+	git diff-tree -p --exit-code -Snot-found HEAD^ HEAD -- b
+	test $? = 0
+'
+test_expect_success 'git diff-files' '
+	echo 3 >>c && {
+		git diff-files --exit-code
+		test $? = 1
+	}
+'
+test_expect_success 'git diff-index --cached HEAD' '
+	git update-index c && {
+		git diff-index --exit-code --cached HEAD
+		test $? = 1
+	}
+'
+
+test_done
diff --git a/t/t4017-quiet.sh b/t/t4017-quiet.sh
new file mode 100755
index 000000000..e747e8422
--- /dev/null
+++ b/t/t4017-quiet.sh
@@ -0,0 +1,80 @@
+#!/bin/sh
+
+test_description='Return value of diffs'
+
+. ./test-lib.sh
+
+test_expect_success 'setup' '
+	echo 1 >a &&
+	git add . &&
+	git commit -m first &&
+	echo 2 >b &&
+	git add . &&
+	git commit -a -m second
+'
+
+test_expect_success 'git diff-tree HEAD^ HEAD' '
+	git diff-tree --quiet HEAD^ HEAD >cnt
+	test $? = 1 && test $(wc -l <cnt) = 0
+'
+test_expect_success 'git diff-tree HEAD^ HEAD -- a' '
+	git diff-tree --quiet HEAD^ HEAD -- a >cnt
+	test $? = 0 && test $(wc -l <cnt) = 0
+'
+test_expect_success 'git diff-tree HEAD^ HEAD -- b' '
+	git diff-tree --quiet HEAD^ HEAD -- b >cnt
+	test $? = 1 && test $(wc -l <cnt) = 0
+'
+# this diff outputs one line: sha1 of the given head
+test_expect_success 'echo HEAD | git diff-tree --stdin' '
+	echo $(git rev-parse HEAD) | git diff-tree --quiet --stdin >cnt
+	test $? = 1 && test $(wc -l <cnt) = 1
+'
+test_expect_success 'git diff-tree HEAD HEAD' '
+	git diff-tree --quiet HEAD HEAD >cnt
+	test $? = 0 && test $(wc -l <cnt) = 0
+'
+test_expect_success 'git diff-files' '
+	git diff-files --quiet >cnt
+	test $? = 0 && test $(wc -l <cnt) = 0
+'
+test_expect_success 'git diff-index --cached HEAD' '
+	git diff-index --quiet --cached HEAD >cnt
+	test $? = 0 && test $(wc -l <cnt) = 0
+'
+test_expect_success 'git diff-index --cached HEAD^' '
+	git diff-index --quiet --cached HEAD^ >cnt
+	test $? = 1 && test $(wc -l <cnt) = 0
+'
+test_expect_success 'git diff-index --cached HEAD^' '
+	echo text >>b &&
+	echo 3 >c &&
+	git add . && {
+		git diff-index --quiet --cached HEAD^ >cnt
+		test $? = 1 && test $(wc -l <cnt) = 0
+	}
+'
+test_expect_success 'git diff-tree -Stext HEAD^ HEAD -- b' '
+	git commit -m "text in b" && {
+		git diff-tree --quiet -Stext HEAD^ HEAD -- b >cnt
+		test $? = 1 && test $(wc -l <cnt) = 0
+	}
+'
+test_expect_success 'git diff-tree -Snot-found HEAD^ HEAD -- b' '
+	git diff-tree --quiet -Snot-found HEAD^ HEAD -- b >cnt
+	test $? = 0 && test $(wc -l <cnt) = 0
+'
+test_expect_success 'git diff-files' '
+	echo 3 >>c && {
+		git diff-files --quiet >cnt
+		test $? = 1 && test $(wc -l <cnt) = 0
+	}
+'
+test_expect_success 'git diff-index --cached HEAD' '
+	git update-index c && {
+		git diff-index --quiet --cached HEAD >cnt
+		test $? = 1 && test $(wc -l <cnt) = 0
+	}
+'
+
+test_done