umpf: answer interactive prompts with default when --default set

When building or tagging an umpf, umpf can ask which branch to use when
multiple are available. Piping yes(1) into umpf in this case doesn't
work, because the variable populated by read in that case is left empty.

Provide for this use case, a --default option that will take a default
if one is known.

Signed-off-by: Ahmad Fatoum <[email protected]>

umpf

@@ -37,6 +37,7 @@ FLAGS=""
 PATCH_DIR="umpf-patches"
 IDENTICAL=false
 STABLE=false
+DEFAULT=false
 FORCE=false
 UPDATE=false
 VERBOSE=false
@@ -173,6 +174,7 @@ usage() {
 	usage: $0 [<options>] [--] <command>
 
 	Mandatory arguments to long options are mandatory for short options too.
+	      --default              answer interactive prompts with the default option
 	      --auto-rerere          automatically try to use rerere after conflicts
 	      --bb                   with format-patch: write patch series for bitbake
 	      --nix                  with format-patch: write patch series nix
@@ -245,7 +247,7 @@ setup() {
 	fi
 
 	o="fhilsub:n:p:r:v:"
-	l="auto-rerere,bb,nix,flags:,force,help,identical,stable,update,base:,name:,patchdir:,relative:,override:,remote:,local,version:"
+	l="auto-rerere,bb,nix,flags:,default,force,help,identical,stable,update,base:,name:,patchdir:,relative:,override:,remote:,local,version:"
 	if ! args="$(getopt -n umpf -o "${o}" -l "${l}" -- "${@}")"; then
 		usage
 		exit 1
@@ -268,6 +270,9 @@ setup() {
 		--nix)
 			NIX=true
 			;;
+		--default)
+			DEFAULT=true
+			;;
 		-f|--force)
 			FORCE=true
 			;;
@@ -414,6 +419,16 @@ nice_branch() {
 	read -r -a replies < <(sed -r -n 's,^(remotes/([^/]*)/|heads/)?(.*),\3 \2,p' <<< "${1}")
 }
 
+read_interactive() {
+	local prompt="$1" def="$2"
+	if ${DEFAULT} && [ -n "${def}" ]; then
+		echo "${prompt}: ${def}"
+		choice="${def}"
+	else
+		read -e -i "${def}" -p "${prompt}: " choice
+	fi
+}
+
 find_branch_rev() {
 	local name branch remote
 	local -a branches replies
@@ -447,8 +462,8 @@ find_branch_rev() {
 			fi
 			i=$((i+1))
 		done
-		read -e -i ${def} -p "branch number: " i
-		nice_branch "${branches[$i]}"
+		read_interactive "branch number" "${def}"
+		nice_branch "${branches[$choice]}"
 		remote="${replies[1]:-refs/heads}/"
 		if [ -z "${GIT_REMOTE}" ]; then
 			GIT_REMOTE="${remote}"
@@ -472,8 +487,7 @@ find_branch_rev() {
 			info "Warning: The following commits are in '${branch}' but not in '${remote}${name}':"
 			GIT_PAGER="" ${GIT} log --oneline "${reply}...${b}"
 			if tty -s; then
-				local choice=""
-				read -e -i n -p "Use ${branch} instead? [y/n]: " choice
+				read_interactive "Use ${branch} instead? [y/n]" "n"
 				if [ "${choice}" == "y" ]; then
 					reply="${b}"
 				fi
@@ -511,7 +525,8 @@ find_branch_name() {
 	0)
 		info "No branch found for ${mergelog}"
 		candidate=$(sed -n "s/^[0-9a-f]* Merge.* '\([^ ]*\)' .*/\1/p" <<< "${mergelog}")
-		read -e -i "${candidate}" -p "topic: " name
+		read_interactive "topic" "${candidate}"
+		name="${choice}"
 		;;
 	1)
 		nice_branch "${branches[0]}"
@@ -646,7 +661,8 @@ import_series() {
 
 	if [ -z "${BASE}" ]; then
 		BASE="$(${GIT} describe "${base_rev}" 2>/dev/null)"
-		read -e -i "${BASE}" -p "base: " BASE
+		read_interactive "base" "${BASE}"
+		BASE="${choice}"
 	fi
 	echo "# umpf-base: ${BASE}" >> "${series}"
 	if [ -n "${GIT_RELATIVE}" ]; then
@@ -1680,7 +1696,7 @@ apply_to_topic() {
 	esac
 
 	while [ -z "${topic}" ]; do
-		local i=0 ret default
+		local i=0 default
 		for branch in "${branch_names[@]}"; do
 			echo "${i}) ${branch}"
 			if git log --pretty="format:%s" "${base}..${branches[${i}]}" | grep -q "^${match}$"; then
@@ -1690,8 +1706,8 @@ apply_to_topic() {
 		done
 		echo "s) show patch"
 		echo "x) skip patch"
-		read -e -p "Branch: " -i "${default}" ret
-		case "${ret}" in
+		read_interactive "Branch" "${default}"
+		case "${choice}" in
 		s)
 			${GIT} show "${rev}"
 			continue
@@ -1700,23 +1716,23 @@ apply_to_topic() {
 			return
 			;;
 		[0-9]*)
-			branch="${branch_names[${ret}]}"
+			branch="${branch_names[${choice}]}"
 			if [ -z "${branch}" ]; then
-				echo "'$ret' is not a valid branch number"
+				echo "'$choice' is not a valid branch number"
 			fi
 			;;
 		*)
-			echo "Invalid command '$ret'"
+			echo "Invalid command '$choice'"
 			continue
 		esac
 		if ! topic="$(${GIT} rev-parse -q --verify "refs/umpf/${branch}^{}")"; then
-			topic="${branches[${ret}]}"
+			topic="${branches[${choice}]}"
 		fi
 		if [ -z "${topic}" ]; then
 			local reply
 			IDENTICAL=false find_branch_rev "${branch}"
 			topic="${reply}"
-			branches[${ret}]="${topic}"
+			branches[${choice}]="${topic}"
 		fi
 		echo "${branch}" > "${STATE}/distribute-branch"
 		echo "${topic}" > "${STATE}/distribute-topic"