anchor.diff:              r-cran-tidyr \
               r-cran-uuid \
               r-cran-viridis \
  -            r-cran-withr
  -
  -# these are not packaged in ubuntu bionic yet
  +            r-cran-withr \
  +            lsb-release
  +
  +# these are not in ubuntu bionic so we install from versioned sources
   
   # github ref is version 2.0.1
   RUN Rscript -e "devtools::install_github('cran/leaflet', ref = 'e0019db', upgrade_dependencies = FALSE)"
  
positive.code:             r-cran-openssl \
              r-cran-pbdzmq \
              r-cran-png \
              r-cran-raster \
              r-cran-rcolorbrewer \
              r-cran-repr \
              r-cran-rjson \
              r-cran-rpart \
              r-cran-shiny \
              r-cran-sp \
  
negative.code: 
  # github ref is version 1.3-2
  RUN Rscript -e "devtools::install_github('cran/rgdal', ref = '8ae242d', upgrade_dependencies = FALSE)"
  
  ENV RSTUDIO_URL https://download2.rstudio.org/rstudio-server-1.1.453-amd64.deb
  ENV RSTUDIO_CHECKSUM 3c546fa9067f48ed1a342f810fca8be6
  
  # install rstudio
  RUN curl --silent --location --fail ${RSTUDIO_URL} > /tmp/rstudio.deb && \
      echo "${RSTUDIO_CHECKSUM} /tmp/rstudio.deb" | md5sum -c - && \
      dpkg -i /tmp/rstudio.deb && \
      rm /tmp/rstudio.deb
  
  RUN echo 'PATH=${PATH}:/usr/lib/rstudio-server/bin' > \
  	/etc/profile.d/site-rstudio.sh
  
  RUN apt-get purge && apt-get clean
  
  