Merge pull request #85 from nix-community/revert-async-nix-shell

Revert "async nix-shell"

direnvrc

@@ -130,6 +130,21 @@ use_flake() {
   export XDG_DATA_DIRS=$XDG_DATA_DIRS${old_xdg_data_dirs:+":"}$old_xdg_data_dirs
 }
 
+_nix_extract_direnv() {
+  local found_direnv
+  found_direnv=0
+  while read -r line; do
+    if [[ "$found_direnv" == "1" ]]; then
+      echo "$line"
+      break
+    elif [[ "$line" == "_____direnv_____" ]]; then
+      found_direnv=1
+    else
+      echo "$line" >&2
+    fi
+  done
+}
+
 use_nix() {
   local path layout_dir
   path=$("${NIX_BIN_PREFIX}nix-instantiate" --find-file nixpkgs)
@@ -164,6 +179,7 @@ use_nix() {
 
   local cache="${layout_dir}/cache-${version:-unknown}"
 
+  local update_drv=0
   if [[ ! -e "$cache"
      || "$HOME/.direnvrc" -nt "$cache"
      || .envrc -nt "$cache"
@@ -172,49 +188,30 @@ use_nix() {
      ]];
   then
     [[ -d "$layout_dir" ]] || mkdir -p "$layout_dir"
-    bash -c '
-      cache=$1
-      shift
-      direnv=$1
-      shift
-      _nix_extract_direnv() {
-        local found_direnv
-        found_direnv=0
-        while read -r line; do
-          if [[ "$found_direnv" == "1" ]]; then
-            echo "$line"
-            break
-          elif [[ "$line" == "_____direnv_____" ]]; then
-            found_direnv=1
-          else
-            echo "$line" >&2
-          fi
-        done
-      }
-      dump_cmd="echo _____direnv_____; $direnv dump bash"
-      tmp=$("${NIX_BIN_PREFIX}nix-shell" \
-          "${experimental_flags[@]}" \
-          --show-trace --pure "$@" --run "$dump_cmd")
-      # show original shell hook output
-      echo "$tmp" | _nix_extract_direnv >&2 > "$cache"
-      # retrigger direnv
-      [[ -f .envrc ]] && touch .envrc
-    ' -- "$cache" "$direnv" "$@" 3>- &
-    echo "renew cache in background"
+    local dump_cmd tmp
+    dump_cmd="echo _____direnv_____; \"$direnv\" dump bash"
+    tmp=$("${NIX_BIN_PREFIX}nix-shell" \
+      "${experimental_flags[@]}" \
+      --show-trace --pure "$@" --run "$dump_cmd")
+    # show original shell hook output
+    echo "$tmp" | _nix_extract_direnv >&2 > "$cache"
+    update_drv=1
   else
-    log_status eval "$cache"
-    read -r cache_content < "$cache"
-    _nix_import_env "$cache_content"
+    log_status using cached derivation
+  fi
 
-    # This part is based on https://discourse.nixos.org/t/what-is-the-best-dev-workflow-around-nix-shell/418/4
-    if [[ "${out:-}" != "" ]]; then
-      local drv_link="${layout_dir}/drv" drv
-      drv=$("${NIX_BIN_PREFIX}nix" show-derivation "$out" \
-        "${experimental_flags[@]}" \
-        | grep -E -o -m1 '/nix/store/.*.drv')
-      _nix_add_gcroot "$drv" "$drv_link"
-      log_status update derivation link
-    fi
+  log_status eval "$cache"
+  read -r cache_content < "$cache"
+  _nix_import_env "$cache_content"
+
+  # This part is based on https://discourse.nixos.org/t/what-is-the-best-dev-workflow-around-nix-shell/418/4
+  if [[ "${out:-}" != "" ]] && (( update_drv )); then
+    local drv_link="${layout_dir}/drv" drv
+    drv=$("${NIX_BIN_PREFIX}nix" show-derivation "$out" \
+      "${experimental_flags[@]}" \
+      | grep -E -o -m1 '/nix/store/.*.drv')
+    _nix_add_gcroot "$drv" "$drv_link"
+    log_status renewed cache and derivation link
   fi
 
   if [[ "$#" == 0 ]]; then