simple check for conda directories

Author: Fi50

scripts/build-setup.sh

@@ -156,6 +156,15 @@ if run_step "1"; then
     # note: lock file must end in .conda-lock.yml - see https://github.com/conda-incubator/conda-lock/issues/154
     CONDA_REQS=$CYDIR/conda-reqs
     CONDA_LOCK_REQS=$CONDA_REQS/conda-lock-reqs
+
+    # check if directories already exist
+    if [ -d "$CONDA_REQS" ] || [ -d "$CONDA_LOCK_REQS"]; then
+        echo "Error: Directories $CONDA_REQS and/or "$CONDA_LOCK_REQS" already exist! \
+Delete them before trying to recreate the conda environment or \`source env.sh\` \
+and skip this step with \`-s 1\`." >&2
+        exit 1
+    fi
+
     # must match with the file generated by generate-conda-lockfile.sh
     if [ "$USE_LEAN_CONDA" = false ]; then
       LOCKFILE=$CONDA_LOCK_REQS/conda-requirements-$TOOLCHAIN_TYPE-linux-64.conda-lock.yml