Revert "add nix chroot fallback"

This reverts commit d7cea4b.

Author: jul-sh

scripts/run-in-nix.sh

@@ -1,105 +1,32 @@
 #!/usr/bin/env bash
 #
-# Run a command inside the Nix development environment.
-# Fallback order:
-#   1) host nix
-#   2) docker (nixos/nix)
-#   3) rootless nix-user-chroot bootstrap (requires user namespaces + cargo)
+# Run a command inside the Nix development environment with a Docker fallback.
 
 set -euo pipefail
 
 ROOT_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")/.." && pwd)"
 export PYTHONPATH="${PYTHONPATH:+$PYTHONPATH:}${ROOT_DIR}"
 
-log() { echo "[$(basename "$0")] $*" >&2; }
-die() { log "ERROR: $*"; exit 1; }
-
 # Handle standard SHELL interface: -c "command"
-if [[ "${1:-}" == "-c" ]]; then
+if [ "$1" = "-c" ]; then
   shift
   set -- bash -c "$@"
 fi
 
-# If we're already inside a nix shell/dev env, just run.
-if [[ -n "${IN_NIX_SHELL:-}" ]]; then
+if [ -n "${IN_NIX_SHELL:-}" ]; then
   exec "$@"
 fi
 
-NIX_FLAKE="${NIX_FLAKE:-$ROOT_DIR#default}"
-NIX_EXPERIMENTAL="${NIX_EXPERIMENTAL:-nix-command flakes}"
-
-run_with_host_nix() {
-  exec nix develop --experimental-features "$NIX_EXPERIMENTAL" \
-    "$NIX_FLAKE" --command "$ROOT_DIR/scripts/run-in-nix.sh" "$@"
-}
-
-run_with_docker() {
-  exec docker run --rm -v "$ROOT_DIR:/app" -w /app nixos/nix \
-    nix develop --experimental-features "$NIX_EXPERIMENTAL" \
-    ".#default" --command /app/scripts/run-in-nix.sh "$@"
-}
-
-run_with_user_chroot() {
-  # 0) Require user namespaces
-  if ! unshare --user --pid bash -lc 'echo YES' >/dev/null 2>&1; then
-    die "user namespaces not available (unshare --user --pid failed); cannot use nix-user-chroot fallback"
-  fi
-
-  # 1) Require cargo to build nix-user-chroot
-  command -v cargo >/dev/null 2>&1 || die "cargo not found; cannot build nix-user-chroot fallback"
-
-  # 2) Workspace-local installs and state (cache these paths in CI if you can)
-  CACHE_DIR="${NIX_CHROOT_CACHE_DIR:-$ROOT_DIR/.cache}"
-  CARGO_ROOT="${NIX_CHROOT_CARGO_ROOT:-$CACHE_DIR/cargo}"
-  CHROOT_ROOT="${NIX_CHROOT_ROOT:-$CACHE_DIR/nix-chroot}"
-  CHROOT_HOME="${NIX_CHROOT_HOME:-$CACHE_DIR/nix-home}"
-
-  mkdir -p "$CARGO_ROOT" "$CHROOT_ROOT" "$CHROOT_HOME"
-
-  # Nix installer needs xz to unpack the tarball on most distros
-  command -v xz >/dev/null 2>&1 || die "xz not found (install xz-utils/xz); nix installer will fail without it"
-
-  # 3) Ensure nix-user-chroot exists (install locally via cargo)
-  export PATH="$CARGO_ROOT/bin:$PATH"
-  if ! command -v nix-user-chroot >/dev/null 2>&1; then
-    local nuc_ver="${NIX_USER_CHROOT_VERSION:-1.2.2}"
-    log "building nix-user-chroot (cargo install) into $CARGO_ROOT ..."
-    cargo install --root "$CARGO_ROOT" "nix-user-chroot@${nuc_ver}"
-  fi
-
-  # 4) Install Nix inside the chroot if missing
-  local nix_bin_host_path="$CHROOT_ROOT/nix/var/nix/profiles/default/bin/nix"
-  if [[ ! -x "$nix_bin_host_path" ]]; then
-    log "bootstrapping nix inside user chroot at $CHROOT_ROOT ..."
-    nix-user-chroot "$CHROOT_ROOT" bash -lc '
-      set -euo pipefail
-      export HOME="'"$CHROOT_HOME"'"
-      mkdir -p "$HOME"
-      curl -L https://nixos.org/nix/install | sh -s -- --no-daemon --yes --no-modify-profile --no-channel-add
-    '
-  fi
-
-  # 5) Run nix develop inside the chroot
-  # nix-user-chroot uses /nix/etc/nix (not /etc/nix); set NIX_CONF_DIR explicitly.
-  exec nix-user-chroot "$CHROOT_ROOT" bash -lc '
-    set -euo pipefail
-    export HOME="'"$CHROOT_HOME"'"
-    export NIX_CONF_DIR=/nix/etc/nix
-    # Ensure nix is on PATH for this non-interactive shell
-    . /nix/etc/profile.d/nix.sh
-    exec nix develop --experimental-features "'"$NIX_EXPERIMENTAL"'" "'"$NIX_FLAKE"'" --command "$1" "${@:2}"
-  ' run-in-chroot "$ROOT_DIR/scripts/run-in-nix.sh" "$@"
-}
-
 if command -v nix >/dev/null 2>&1; then
-  run_with_host_nix "$@"
-fi
-
-log "Nix is not available."
-if command -v docker >/dev/null 2>&1; then
-  log "Attempting Docker fallback (nixos/nix)."
-  run_with_docker "$@"
+  exec nix develop --experimental-features 'nix-command flakes' "$ROOT_DIR#default" --command "$ROOT_DIR/scripts/run-in-nix.sh" "$@" 2>/dev/null
+else
+  echo "Nix is not available. Attempting to use Docker with Nix image."
+  if command -v docker >/dev/null 2>&1; then
+    echo "Docker is available, running script inside a Nix container."
+    exec docker run --rm -v "$ROOT_DIR:/app" -w /app nixos/nix \
+      nix develop --experimental-features 'nix-command flakes' .#default --command /app/scripts/run-in-nix.sh "$@"
+  else
+    echo "Docker is not available. Please install either Nix or Docker to proceed."
+    exit 1
+  fi
 fi
-
-log "Docker is not available; attempting nix-user-chroot bootstrap fallback."
-run_with_user_chroot "$@"