[PATCH 2/2] git-quiltimport: flip the default not to allow fuzz

[Junio C Hamano <gitster@pobox.com>]

Trying to be as strict as possible when applying the patch may be a
good discipline, so let's flip the default but we can be helpful to
those who do rely on the original behaviour thanks to the previous
change to add -C$n option.

Suggest using -C1 when (and only when):

 - "git apply" without fuzz fails to apply; and
 - the user did not specify a -C$n or --exact option; and
 - "git apply -C1" (old behaviour) would have succeeded.

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

 * And this is the "flipping of the default"

 git-quiltimport.sh | 26 ++++++++++++++++++++++++--
 1 file changed, 24 insertions(+), 2 deletions(-)

diff --git a/git-quiltimport.sh b/git-quiltimport.sh
index 929365f..1190eb9 100755
--- a/git-quiltimport.sh
+++ b/git-quiltimport.sh
@@ -15,7 +15,8 @@ SUBDIRECTORY_ON=Yes
 
 dry_run=""
 quilt_author=""
-cflag=-C1
+cflag=
+fuzz_specified=
 while test $# != 0
 do
 	case "$1" in
@@ -31,9 +32,11 @@ do
 		*) ;;
 		esac
 		cflag="-C$1"
+		fuzz_specified=yes
 		;;
 	--exact)
 		cflag=
+		fuzz_specified=yes
 		;;
 	-n|--dry-run)
 		dry_run=1
@@ -74,6 +77,25 @@ tmp_msg="$tmp_dir/msg"
 tmp_patch="$tmp_dir/patch"
 tmp_info="$tmp_dir/info"
 
+# Helper to warn about -C$n option
+do_apply () {
+	if git apply --index ${cflag+"$cflag"} "$@"
+	then
+		return
+	fi
+	if test -z "$fuzz_specified" &&
+	   git apply --check --index -C1 "$@" >/dev/null 2>&1
+	then
+		cat >&2 <<-\EOM
+		'git quiltimport' by default no longer attempts to apply
+		patches with reduced context lines to allow fuzz; if you
+		want the old 'unsafe' behaviour, run the command with -C1
+		option.
+		EOM
+
+	fi
+	return 1
+}
 
 # Find the initial commit
 commit=$(git rev-parse HEAD)
@@ -145,7 +167,7 @@ do
 	fi
 
 	if [ -z "$dry_run" ] ; then
-		git apply --index $cflag ${level:+"$level"} "$tmp_patch" &&
+		do_apply ${level:+"$level"} "$tmp_patch" &&
 		tree=$(git write-tree) &&
 		commit=$( (echo "$SUBJECT"; echo; cat "$tmp_msg") | git commit-tree $tree -p $commit) &&
 		git update-ref -m "quiltimport: $patch_name" HEAD $commit || exit 4
-- 
2.1.2-583-g325e495