diff: add config option relative

The `diff.relative` boolean option set to `true` shows only changes in
the current directory/value specified by the `path` argument of the
`relative` option and shows pathnames relative to the aforementioned
directory.

Teach `--no-relative` to override earlier `--relative`

Add for git-format-patch(1) options documentation `--relative` and
`--no-relative`

Signed-off-by: Laurent Arnoud <laurent@spkdev.net>
Acked-by: Đoàn Trần Công Danh <congdanhqx@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

2 files changed, 92 insertions, 3 deletions

diff --git a/t/t4014-format-patch.sh b/t/t4014-format-patch.sh
index db7e733af9..575e079cc2 100755
--- a/t/t4014-format-patch.sh
+++ b/t/t4014-format-patch.sh
@@ -1602,6 +1602,19 @@ test_expect_success 'format patch ignores color.ui' '
 	test_cmp expect actual
 '
 
+test_expect_success 'format patch respects diff.relative' '
+	rm -rf subdir &&
+	mkdir subdir &&
+	echo other content >subdir/file2 &&
+	git add subdir/file2 &&
+	git commit -F msg &&
+	test_unconfig diff.relative &&
+	git format-patch --relative=subdir --stdout -1 >expect &&
+	test_config diff.relative true &&
+	git -C subdir format-patch --stdout -1 >actual &&
+	test_cmp expect actual
+'
+
 test_expect_success 'cover letter with invalid --cover-from-description and config' '
 	test_config branch.rebuild-1.description "config subject
 
diff --git a/t/t4045-diff-relative.sh b/t/t4045-diff-relative.sh
index 258808708e..7be1de736d 100755
--- a/t/t4045-diff-relative.sh
+++ b/t/t4045-diff-relative.sh
@@ -8,7 +8,8 @@ test_expect_success 'setup' '
 	echo content >file1 &&
 	mkdir subdir &&
 	echo other content >subdir/file2 &&
-	blob=$(git hash-object subdir/file2) &&
+	blob_file1=$(git hash-object file1) &&
+	blob_file2=$(git hash-object subdir/file2) &&
 	git add . &&
 	git commit -m one
 '
@@ -18,7 +19,7 @@ check_diff () {
 	shift
 	expect=$1
 	shift
-	short_blob=$(git rev-parse --short $blob)
+	short_blob=$(git rev-parse --short $blob_file2)
 	cat >expected <<-EOF
 	diff --git a/$expect b/$expect
 	new file mode 100644
@@ -70,7 +71,7 @@ check_raw () {
 	expect=$1
 	shift
 	cat >expected <<-EOF
-	:000000 100644 $ZERO_OID $blob A	$expect
+	:000000 100644 $ZERO_OID $blob_file2 A	$expect
 	EOF
 	test_expect_success "--raw $*" "
 		git -C '$dir' diff --no-abbrev --raw $* HEAD^ >actual &&
@@ -86,4 +87,79 @@ do
 	check_$type . dir/file2 --relative=sub
 done
 
+check_diff_relative_option () {
+	dir=$1
+	shift
+	expect=$1
+	shift
+	relative_opt=$1
+	shift
+	test_expect_success "config diff.relative $relative_opt -p $*" "
+		short_blob=\$(git rev-parse --short $blob_file2) &&
+		cat >expected <<-EOF &&
+		diff --git a/$expect b/$expect
+		new file mode 100644
+		index 0000000..\$short_blob
+		--- /dev/null
+		+++ b/$expect
+		@@ -0,0 +1 @@
+		+other content
+		EOF
+		test_config -C $dir diff.relative $relative_opt &&
+		git -C '$dir' diff -p $* HEAD^ >actual &&
+		test_cmp expected actual
+	"
+}
+
+check_diff_no_relative_option () {
+	dir=$1
+	shift
+	expect=$1
+	shift
+	relative_opt=$1
+	shift
+	test_expect_success "config diff.relative $relative_opt -p $*" "
+		short_blob_file1=\$(git rev-parse --short $blob_file1) &&
+		short_blob_file2=\$(git rev-parse --short $blob_file2) &&
+		cat >expected <<-EOF &&
+		diff --git a/file1 b/file1
+		new file mode 100644
+		index 0000000..\$short_blob_file1
+		--- /dev/null
+		+++ b/file1
+		@@ -0,0 +1 @@
+		+content
+		diff --git a/$expect b/$expect
+		new file mode 100644
+		index 0000000..\$short_blob_file2
+		--- /dev/null
+		+++ b/$expect
+		@@ -0,0 +1 @@
+		+other content
+		EOF
+		test_config -C $dir diff.relative $relative_opt &&
+		git -C '$dir' diff -p $* HEAD^ >actual &&
+		test_cmp expected actual
+	"
+}
+
+check_diff_no_relative_option . subdir/file2 false
+check_diff_no_relative_option . subdir/file2 true --no-relative
+check_diff_no_relative_option . subdir/file2 false --no-relative
+check_diff_no_relative_option subdir subdir/file2 false
+check_diff_no_relative_option subdir subdir/file2 true --no-relative
+check_diff_no_relative_option subdir subdir/file2 false --no-relative
+
+check_diff_relative_option . file2 false --relative=subdir/
+check_diff_relative_option . file2 false --relative=subdir
+check_diff_relative_option . file2 true --relative=subdir/
+check_diff_relative_option . file2 true --relative=subdir
+check_diff_relative_option subdir file2 false --relative
+check_diff_relative_option subdir file2 true --relative
+check_diff_relative_option subdir file2 true
+check_diff_relative_option subdir file2 false --no-relative --relative
+check_diff_relative_option subdir file2 true --no-relative --relative
+check_diff_relative_option . file2 false --no-relative --relative=subdir
+check_diff_relative_option . file2 true --no-relative --relative=subdir
+
 test_done