[PATCH] tg export: implement skipping empty patches for quilt mode

@@ -7,6 +7,7 @@ name=
 branches=
 output=
 driver=collapse
+skipempty=false
 
 
 ## Parse options

@@ -20,6 +21,8 @@ while [ -n "$1" ]; do
 		driver=quilt;;
 	--collapse)
 		driver=collapse;;
+	-n)
+		skipempty=true;;
 	-*)
 		echo "Usage: tg [...] export ([--collapse] NEWBRANCH | [-b BRANCH1,BRANCH2...] --quilt DIRECTORY)" >&2
 		exit 1;;

@@ -34,6 +37,9 @@ done
 [ -z "$branches" -o "$driver" = "quilt" ] ||
 	die "-b works only with the quilt driver"
 
+! "$skipempty" || [ "$driver" = "quilt" ] ||
+	die "-n is only implemented for the quilt driver"
+
 if [ -z "$branches" ]; then
 	# this check is only needed when no branches have been passed
 	name="$(git symbolic-ref HEAD | sed 's#^refs/heads/##')"

@@ -140,10 +146,14 @@ quilt()
 		return
 	fi
 
-	echo "Exporting $_dep"
-	mkdir -p "$(dirname "$filename")"
-	$tg patch "$_dep" >"$filename"
-	echo "$_dep.diff -p1" >>"$output/series"
+	if "$skipempty" && branch_empty "$_dep"; then
+		echo "Skip empty patch $_dep";
+	else
+		echo "Exporting $_dep"
+		mkdir -p "$(dirname "$filename")"
+		$tg patch "$_dep" >"$filename"
+		echo "$_dep.diff -p1" >>"$output/series"
+	fi
 }