fix: r dependencies on non root context dir (#219)

Author: SalimKayal

buildpacks/r-dependency-manager/bin/build

@@ -4,9 +4,13 @@ set -eou pipefail
 echo -e "=== 🔧 \033[1mRenku R/renv dependency manager buildpack\033[0m ==="
 
 layer_dir="${CNB_LAYERS_DIR}/r-deps"
+env_dir="${layer_dir}/env"
 buildpack_dir="${CNB_BUILDPACK_DIR}"
 execd_dir="${layer_dir}"/exec.d
 mkdir -p "${execd_dir}"
+mkdir -p "${env_dir}"
+
+printf "%s" "${PWD}" > "${env_dir}/ENV_SOURCE_DIR.default"
 
 cp "${buildpack_dir}/bin/setup.sh" "${execd_dir}"/setup.sh
 chmod +x "${execd_dir}"/setup.sh

buildpacks/r-dependency-manager/bin/setup.sh

@@ -2,7 +2,7 @@
 set -eo pipefail
 
 export RENV_PATHS_ROOT="${RENKU_MOUNT_DIR}/.rstudio/cache:${RENV_PATHS_ROOT}"
-export ORIGINAL_LOCKFILE="/workspace/renv.lock"
+export ORIGINAL_LOCKFILE="${ENV_SOURCE_DIR}/renv.lock"
 
 # shellcheck disable=SC2016
 # NOTE: If there is a mistmatch between R_HOME env var and Rscript a warning shows up in stdout