[PATCH] Use clean.requireforce to protect untracked files.

[Jiang Xin <worldhello.net@gmail.com>]

Untracked files may be significant for certain repositories, but if run the
command "git clean -fdx" by accident, all untracked files will be lost.

This hack adds three values in addtion to true/false to "clean.requireforce",
which can protect untracked files from cleaning:

* true or unset : can not clean without -f/--force option provided.
* false         : clean untracked files just as -f/--force option provided.
* lockignored   : can not clean untracked ignored files.
* lockunignored : can not clean untracked unignored files.
* lockall       : can not clean anything.

Signed-off-by: Jiang Xin <jiangxin@ossxp.com>
---
 Documentation/config.txt |    7 +++-
 builtin/clean.c          |   29 ++++++++++++++++++-
 t/t7300-clean.sh         |   69 ++++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 101 insertions(+), 4 deletions(-)

diff --git a/Documentation/config.txt b/Documentation/config.txt
index 6b93777..b930f42 100644
--- a/Documentation/config.txt
+++ b/Documentation/config.txt
@@ -684,8 +684,11 @@ browser.<tool>.path::
 	working repository in gitweb (see linkgit:git-instaweb[1]).
 
 clean.requireForce::
-	A boolean to make git-clean do nothing unless given -f
-	or -n.   Defaults to true.
+	When set to `LockIgnored`, cleaning untracked ignored files is
+	denied. When set to `LockUnIgnored`, only allow cleaning untracked
+	ignored files using -X option. When set to `LockAll`, no files
+	can be cleaned until unset this variable. A boolean to make
+	git-clean do nothing unless given -f or -n. Defaults to true.
 
 color.branch::
 	A boolean to enable/disable color in the output of
diff --git a/builtin/clean.c b/builtin/clean.c
index 75697f7..441f35a 100644
--- a/builtin/clean.c
+++ b/builtin/clean.c
@@ -13,7 +13,11 @@
 #include "string-list.h"
 #include "quote.h"
 
+#define LOCK_IGNORED	01
+#define LOCK_UNIGNORED	02
+
 static int force = -1; /* unset */
+static int lock_flag = 0;
 
 static const char *const builtin_clean_usage[] = {
 	"git clean [-d] [-f] [-n] [-q] [-e <pattern>] [-x | -X] [--] <paths>...",
@@ -22,8 +26,17 @@ static const char *const builtin_clean_usage[] = {
 
 static int git_clean_config(const char *var, const char *value, void *cb)
 {
-	if (!strcmp(var, "clean.requireforce"))
-		force = !git_config_bool(var, value);
+	if (!strcmp(var, "clean.requireforce")) {
+		if (value && !strcasecmp(value, "LockIgnored"))
+			lock_flag = LOCK_IGNORED;
+		else if (value && !strcasecmp(value, "LockUnIgnored"))
+			lock_flag = LOCK_UNIGNORED;
+		else if (value && !strcasecmp(value, "LockAll"))
+			lock_flag = LOCK_IGNORED | LOCK_UNIGNORED;
+		else
+			force = !git_config_bool(var, value);
+		return 0;
+	}
 	return git_default_config(var, value, cb);
 }
 
@@ -77,6 +90,18 @@ int cmd_clean(int argc, const char **argv, const char *prefix)
 	if (ignored && ignored_only)
 		die(_("-x and -X cannot be used together"));
 
+	if (!show_only && lock_flag) {
+		if (lock_flag & LOCK_IGNORED && lock_flag & LOCK_UNIGNORED)
+			die(_("clean.requireForce set to LockAll; "
+				  "refusing to clean until reset clean.requireForce"));
+		else if (lock_flag & LOCK_IGNORED && (ignored_only || ignored))
+			die(_("clean.requireForce set to LockIgnored and conflict with -x or -X; "
+				  "refusing to clean"));
+		else if (lock_flag & LOCK_UNIGNORED && !ignored_only)
+			die(_("clean.requireForce set to LockUnIgnored and can only work with -X; "
+				  "refusing to clean"));
+	}
+
 	if (!show_only && !force) {
 		if (config_set)
 			die(_("clean.requireForce set to true and neither -n nor -f given; "
diff --git a/t/t7300-clean.sh b/t/t7300-clean.sh
index 800b536..b4f38dd 100755
--- a/t/t7300-clean.sh
+++ b/t/t7300-clean.sh
@@ -460,4 +460,73 @@ test_expect_success SANITY 'git clean -d with an unreadable empty directory' '
 	! test -d foo
 '
 
+test_expect_success 'clean.requireForce LockIgnored' '
+
+	git config clean.requireForce LockIgnored &&
+	mkdir -p build docs &&
+	touch a.out src/part3.c docs/manual.txt obj.o build/lib.so &&
+	test_must_fail git clean &&
+	test_must_fail git clean -f -x &&
+	test_must_fail git clean -f -X &&
+	git clean -f &&
+	test -f Makefile &&
+	test -f README &&
+	test -f src/part1.c &&
+	test -f src/part2.c &&
+	test ! -f a.out &&
+	test ! -f src/part3.c &&
+	test -f docs/manual.txt &&
+	test -f obj.o &&
+	test -f build/lib.so &&
+	git clean -f -d &&
+	test ! -f docs/manual.txt &&
+	test -f build/lib.so &&
+	git config clean.requireForce true
+'
+
+test_expect_success 'clean.requireForce LockUnIgnored' '
+
+	git config clean.requireForce LockUnIgnored &&
+	mkdir -p build docs &&
+	touch a.out src/part3.c docs/manual.txt obj.o build/lib.so &&
+	test_must_fail git clean &&
+	test_must_fail git clean -f &&
+	test_must_fail git clean -f -x &&
+	git clean -f -X &&
+	test -f Makefile &&
+	test -f README &&
+	test -f src/part1.c &&
+	test -f src/part2.c &&
+	test -f a.out &&
+	test -f src/part3.c &&
+	test -f docs/manual.txt &&
+	test ! -f obj.o &&
+	test -f build/lib.so &&
+	git clean -f -d -X &&
+	test ! -f build/lib.so &&
+	test -f src/part3.c &&
+	git config clean.requireForce true
+'
+
+test_expect_success 'clean.requireForce LockAll' '
+
+	git config clean.requireForce lockall &&
+	mkdir -p build docs &&
+	touch a.out src/part3.c docs/manual.txt obj.o build/lib.so &&
+	test_must_fail git clean -f &&
+	test_must_fail git clean -f -x &&
+	test_must_fail git clean -f -X &&
+	git clean -ndx &&
+	test -f Makefile &&
+	test -f README &&
+	test -f src/part1.c &&
+	test -f src/part2.c &&
+	test -f a.out &&
+	test -f src/part3.c &&
+	test -f docs/manual.txt &&
+	test -f obj.o &&
+	test -f build/lib.so &&
+	git config clean.requireForce true
+'
+
 test_done
-- 
1.7.5.4.1.g6c49.dirty