tools/bazel

#!/usr/bin/env bash
# Both bazelisk and bazel's native wrapper scripts will attempt to use the well-known executable
# named "tools/bazel" to run Bazel. The path of the original executable is stored in BAZEL_REAL.
set -euo pipefail
shopt -s nullglob

DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"

# Jump into nix-shell if BAZEL_REAL is set to a /nix/store path and we aren't
# inside our shell yet.
if [[ "${BAZEL_REAL:-}" == /nix/store/* && -z "${MONOGON_NIXOS:-}" ]]; then
  echo "Detected Nix based bazel installation and we are not in a nix-shell, overriding to nix-shell." >&2
  USE_NIX_SHELL=yes
fi

# If the wrapper is called directly we check if nix-shell is available
# to automagically switch into the nix-shell. Otherwise complain and
# exit.
if [[ -z "${BAZEL_REAL:-}" ]]; then
  if [[ -x $(command -v nix-shell) ]]; then
    echo "BAZEL_REAL is not set and nix-shell is available, overriding to nix-shell" >&2
    USE_NIX_SHELL=yes
  else
    echo "BAZEL_REAL is not set and nix-shell not available. Please check the setup guide." >&2
    exit 1
  fi
fi

if [[ -n "${USE_NIX_SHELL:-}" ]]; then
  # Jump to project root since bwrap hangs if we aren't there
  cd "${DIR}/../"

  export COMMAND="bazel $*"
  export PWD="$OLDPWD"
  exec nix-shell
fi

prechecks() {
  # Recommend using Bazelisk instead of Bazel's "bazel.sh" wrapper.
  # Skip if we're inside the Nix shell (which uses a customized Bazel build).
  if [[ -z "${BAZELISK_SKIP_WRAPPER:-}" && -z "${MONOGON_NIXOS:-}" ]]; then
    echo "############################################################" >&2
    echo "#  Please use Bazelisk to build the Monorepo. Using Bazel  #" >&2
    echo "#  directly may work, but is not recommended or supported. #" >&2
    echo "############################################################" >&2
  fi

  # Our local user needs write access to /dev/kvm. Warn if this is not the case.
  if ! touch /dev/kvm; then
    echo "###################################################################" >&2
    echo "#  Cannot write to /dev/kvm - please verify permissions.          #" >&2
    echo "#  Most tests require KVM and will not work. Builds still work.   #" >&2
    echo "#  On most systems, add your user to the kvm group and re-login.  #" >&2
    echo "###################################################################" >&2
  fi
}

intellij_patch() {
  # When IntelliJ's Bazel plugin uses //scripts/bin/bazel to either build targets
  # or run syncs, it adds a --override_repository flag to the bazel command
  # line that points @intellij_aspect into a path on the filesystem. This
  # external repository contains a Bazel Aspect definition which Bazel
  # executes to provide the IntelliJ Bazel plugin with information about the
  # workspace / build targets / etc...
  #
  # We need to patch the aspect definition to fix a number of bugs
  # to make it work with the Monogon monorepo.

  # Find all IntelliJ installation/config directories.
  local ij_home_paths=("${HOME}/.local/share/JetBrains/IntelliJIdea"*)
  # Get the newest one, if any.
  local ij_home=""
  if ! [[  ${#ij_home_paths[@]} -eq 0 ]]; then
      # Reverse sort paths by name, with the first being the newest IntelliJ
      # installation.
      IFS=$'\n'
      local sorted=($(sort -r <<<"${ij_home_paths[*]}"))
      unset IFS
      ij_home="${sorted[0]}"
  fi


  # If we don't have or can't find ij_home, don't bother with attempting to patch anything.
  if [[ -d "${ij_home}" ]]; then
      # aspect_path is the path to the aspect external repository that IntelliJ will
      # inject into bazel via --override_repository.
      local aspect_path="${ij_home}/ijwb/aspect"
      if [[ -d "${aspect_path}" ]]; then
          # aspect_path is the path to the aspect external repository that IntelliJ will
          # inject into bazel via --override_repository.
          local aspect_path="${ij_home}/ijwb/aspect"
          # Our copy of it.
          local patched_path="${ij_home}/ijwb/aspect-monogon"
          # Checksum of the patch that was used to create patched_path.
          local checksum_file="${patched_path}/checksum"
          # The patch
          local patch_file="${DIR}/../intellij/patches/bazel_intellij_aspect_filter.patch"
          # The checksum of the patch we're about to apply.
          local checksum
          checksum=$(sha256sum "$patch_file" | cut -d' ' -f1)

          # If the patched aspect repository doesn't exist, or the checksum of the patch
          # we're about to apply doesn't match the checksum of the patch that was used
          # to create the patched aspect repository, apply the patch.

          if ! [[ -d "${patched_path}" ]] || ! [[ "$(cat "${checksum_file}")" == "${checksum}" ]]; then
              echo "IntelliJ found at ${ij_home}, patching aspect repository." >&2
              # Copy the aspect repository to the patched path.
              rm -rf "${patched_path}"
              cp -r "${aspect_path}" "${patched_path}"
              # Apply the patch.
              patch -d "${patched_path}" -p1 < "${patch_file}"
              # Write the checksum of the patch to the checksum file.
              echo "${checksum}" > "${checksum_file}"
          else
              echo "IntelliJ found at ${ij_home}, aspect repository already patched." >&2
          fi
      else
        echo "IntelliJ found at ${ij_home}, but aspect repository is missing. Skipping..." >&2
      fi
  fi
}

prechecks
intellij_patch

# Find the --override_repository=intellij_aspect=[path]
# argument in $@ and replace the path with the patched version.
# This is surprisingly tricky - bash special-cases "$@" to expand
# as "$1" "$2" ... "$n" so that argv is preserved, so we need to
# modify the real $@ array.

for i in $(seq 1 $#); do
  if [[ "${!i}" == "--override_repository=intellij_aspect="* ]]; then
    new_arg="${!i/\/aspect/\/aspect-monogon}"
    set -- "${@:1:$((i-1))}" "${new_arg}" "${@:$((i+1))}"
  fi
done

exec -a "$0" "${BAZEL_REAL}" "$@"