clean: require -f to do damage by default

This makes the clean.requireForce configuration default to true.
Too many people are burned by typing "git clean" by mistake when
they meant to say "make clean".

Signed-off-by: Junio C Hamano <gitster@pobox.com>

Documentation/config.txt

@@ -338,8 +338,8 @@ branch.<name>.merge::
 	`.` (a period) for branch.<name>.remote.
 
 clean.requireForce::
-	A boolean to make git-clean do nothing unless given -f or -n.  Defaults
-	to false.
+	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

git-clean.sh

@@ -20,12 +20,16 @@ require_work_tree
 ignored=
 ignoredonly=
 cleandir=
-disabled="`git config --bool clean.requireForce`"
 rmf="rm -f --"
 rmrf="rm -rf --"
 rm_refuse="echo Not removing"
 echo1="echo"
 
+# requireForce used to default to false but now it defaults to true.
+# IOW, lack of explicit "clean.requireForce = false" is taken as
+# "clean.requireForce = true".
+disabled=$(git config --bool clean.requireForce || echo true)
+
 while test $# != 0
 do
 	case "$1" in

t/t7201-co.sh

@@ -77,7 +77,7 @@ test_expect_success "checkout with dirty tree without -m" '
 test_expect_success "checkout -m with dirty tree" '
 
 	git checkout -f master &&
-	git clean &&
+	git clean -f &&
 
 	fill 0 1 2 3 4 5 6 7 8 >one &&
 	git checkout -m side &&
@@ -99,7 +99,7 @@ test_expect_success "checkout -m with dirty tree" '
 
 test_expect_success "checkout -m with dirty tree, renamed" '
 
-	git checkout -f master && git clean &&
+	git checkout -f master && git clean -f &&
 
 	fill 1 2 3 4 5 7 8 >one &&
 	if git checkout renamer
@@ -121,7 +121,7 @@ test_expect_success "checkout -m with dirty tree, renamed" '
 
 test_expect_success 'checkout -m with merge conflict' '
 
-	git checkout -f master && git clean &&
+	git checkout -f master && git clean -f &&
 
 	fill 1 T 3 4 5 6 S 8 >one &&
 	if git checkout renamer
@@ -144,7 +144,7 @@ test_expect_success 'checkout -m with merge conflict' '
 
 test_expect_success 'checkout to detach HEAD' '
 
-	git checkout -f renamer && git clean &&
+	git checkout -f renamer && git clean -f &&
 	git checkout renamer^ &&
 	H=$(git rev-parse --verify HEAD) &&
 	M=$(git show-ref -s --verify refs/heads/master) &&
@@ -160,7 +160,7 @@ test_expect_success 'checkout to detach HEAD' '
 
 test_expect_success 'checkout to detach HEAD with branchname^' '
 
-	git checkout -f master && git clean &&
+	git checkout -f master && git clean -f &&
 	git checkout renamer^ &&
 	H=$(git rev-parse --verify HEAD) &&
 	M=$(git show-ref -s --verify refs/heads/master) &&
@@ -176,7 +176,7 @@ test_expect_success 'checkout to detach HEAD with branchname^' '
 
 test_expect_success 'checkout to detach HEAD with HEAD^0' '
 
-	git checkout -f master && git clean &&
+	git checkout -f master && git clean -f &&
 	git checkout HEAD^0 &&
 	H=$(git rev-parse --verify HEAD) &&
 	M=$(git show-ref -s --verify refs/heads/master) &&

t/t7300-clean.sh

@@ -7,6 +7,8 @@ test_description='git-clean basic tests'
 
 . ./test-lib.sh
 
+git config clean.requireForce no
+
 test_expect_success 'setup' '
 
 	mkdir -p src &&
@@ -139,6 +141,13 @@ test_expect_success 'git-clean -d -X' '
 
 '
 
+test_expect_success 'clean.requireForce defaults to true' '
+
+	git config --unset clean.requireForce &&
+	! git-clean
+
+'
+
 test_expect_success 'clean.requireForce' '
 
 	git config clean.requireForce true &&