Update lockfile formating (#2402)

* Use dpkg --list to format stdout to lockfile
to make list of installed package more readable

* Line formating
space new line after each lockfile checksum

* Specify ROS distro for rosdep update

* Strip ros distro install fom AMENT_PREFIX_PATH
to force rosdep to resolve and list apt installed package dependencies
and to not skip them as if they are in the catkin workspace

* Prevent dpkg from listing all installed pacakge
when set of dependencies happens to be empty

* Account single entry case AMENT_PREFIX_PATH

* Unset AMENT_PREFIX_PATH if only ros install path
to prevent rosdep from erroring out on empty var

.circleci/config.yml

@@ -81,13 +81,20 @@ _commands:
             working_directory: << parameters.workspace >>
             command: |
               . << parameters.underlay >>/install/setup.sh
+              AMENT_PREFIX_PATH=$(echo "$AMENT_PREFIX_PATH" | \
+                sed -e 's|:/opt/ros/'$ROS_DISTRO'$||')
+              if [ "$AMENT_PREFIX_PATH" == "/opt/ros/$ROS_DISTRO" ]
+              then
+                unset AMENT_PREFIX_PATH
+              fi
+
               cat << parameters.underlay >>/lockfile.txt > lockfile.txt
               vcs export --exact << parameters.underlay >>/src | \
                 (echo vcs_export && cat) >> lockfile.txt
               sha256sum $PWD/lockfile.txt >> lockfile.txt
-              apt-get update
-              rosdep update
 
+              apt-get update
+              rosdep update --rosdistro $ROS_DISTRO
               dependencies=$(
                 rosdep install -q -y \
                   --from-paths src \
@@ -99,7 +106,7 @@ _commands:
                 awk '$1 ~ /^resolution\:/' | \
                 awk -F'[][]' '{print $2}' | \
                 tr -d \, | xargs -n1 | sort -u | xargs)
-              dpkg -s $dependencies | \
+              dpkg --list dpkg $dependencies | \
                 (echo workspace_dependencies && cat) >> lockfile.txt
               sha256sum $PWD/lockfile.txt >> lockfile.txt
     setup_workspace:
@@ -287,12 +294,15 @@ _steps:
       command: |
         mkdir -p $ROS_WS/src && cd $ROS_WS
         ln -s /opt/ros/$ROS_DISTRO install
+
         echo $CACHE_NONCE | \
           (echo cache_nonce && cat) >> lockfile.txt
         sha256sum $PWD/lockfile.txt >> lockfile.txt
+        
         TZ=utc stat -c '%y' /ros_entrypoint.sh | \
           (echo ros_entrypoint && cat) >> lockfile.txt
         sha256sum $PWD/lockfile.txt >> lockfile.txt
+
         rm -rf $OVERLAY_WS/*
   on_checkout: &on_checkout
     checkout: