Allow git-diff exit with codes similar to diff(1)

This introduces a new command-line option: --exit-code. The diff
programs will return 1 for differences, return 0 for equality, and
something else for errors.

Signed-off-by: Alex Riesen <raa.lkml@gmail.com>
Signed-off-by: Junio C Hamano <junkio@cox.net>

1 files changed, 79 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