mergetool: check return value from read

The process may not even have the standard input open in which case it
will get stuck in an infinite loop to prompt and read nothing.

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

diff --git a/git-mergetool.sh b/git-mergetool.sh
index 3aab5aae844b963fc4178675a56da20e02488dfd..3c157bcd26232c758572bf908add44216cb8e2e7 100755 (executable)
--- a/git-mergetool.sh
+++ b/git-mergetool.sh
@@ -100,7 +100,7 @@ resolve_deleted_merge () {
        else
            printf "Use (c)reated or (d)eleted file, or (a)bort? "
        fi
-       read ans
+       read ans || return 1
        case "$ans" in
            [mMcC]*)
                git add -- "$MERGED"
@@ -122,7 +122,7 @@ resolve_deleted_merge () {
 resolve_submodule_merge () {
     while true; do
        printf "Use (l)ocal or (r)emote, or (a)bort? "
-       read ans
+       read ans || return 1
        case "$ans" in
            [lL]*)
                if ! local_present; then
@@ -249,7 +249,7 @@ merge_file () {
     describe_file "$remote_mode" "remote" "$REMOTE"
     if "$prompt" = true; then
        printf "Hit return to start merge resolution tool (%s): " "$merge_tool"
-       read ans
+       read ans || return 1
     fi
 
     if base_present; then
@@ -320,7 +320,7 @@ done
 prompt_after_failed_merge() {
     while true; do
        printf "Continue merging other unresolved paths (y/n) ? "
-       read ans
+       read ans || return 1
        case "$ans" in
 
            [yY]*)