fix(command): Restore environment variables before calling exec

Previously, the command would overwrite the HOST and PORT variables based on the hostname and port of the service which we would check for being available. This change prevents these variables from being overwritten, which allows you to set them outside the command.

BREAKING CHANGE: HOST, PORT and other internally used environment variables are not overwritten anymore. If you use these, then you need to manually supply them.

wait-for

@@ -22,6 +22,7 @@
 # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 # SOFTWARE.
 
+set -- "$@" -- "$TIMEOUT" "$QUIET" "$HOST" "$PORT" "$result"
 TIMEOUT=15
 QUIET=0
 
@@ -52,7 +53,15 @@ wait_for() {
 
     result=$?
     if [ $result -eq 0 ] ; then
-      if [ $# -gt 0 ] ; then
+      if [ $# -gt 6 ] ; then
+        for result in $(seq $(($# - 6))); do
+          result=$1
+          shift
+          set -- "$@" "$result"
+        done
+
+        TIMEOUT=$2 QUIET=$3 HOST=$4 PORT=$5 result=$6
+        shift 6
         exec "$@"
       fi
       exit 0
@@ -69,8 +78,7 @@ wait_for() {
   exit 1
 }
 
-while [ $# -gt 0 ]
-do
+while :; do
   case "$1" in
     *:* )
     HOST=$(printf "%s\n" "$1"| cut -d : -f 1)

wait-for.bats

@@ -32,3 +32,16 @@
   [ "$status" -ne 0 ]
   [ "$output" != "success" ]
 }
+
+@test "environment variables should be restored for command invocation" {
+  HOST=success run ./wait-for -t 1 google.com:80 -- sh -c 'echo "$HOST"'
+
+  [ "$output" = "success" ]
+}
+
+@test "unset environment variables should be restored as unset for command invocation" {
+  run ./wait-for -t 1 google.com:80 -- sh -uc 'echo "$HOST"'
+
+  [ "$status" -ne 0 ]
+  [ "$output" != "google.com" ]
+}