tools/devshell/contrib/setup-jj

#!/bin/bash
# Copyright 2026 The Fuchsia Authors. All rights reserved.
# Use of this source code is governed by a BSD-style license that can be
# found in the LICENSE file.

#### CATEGORY=Developer Tools
### sets up the jj tool (if installed) for use with Fuchsia.
## Will also set up the watchman config file if watchman is installed and
## a watchman config file does not exist already.

source "$(cd "$(dirname "${BASH_SOURCE[0]}")" >/dev/null 2>&1 && pwd)"/../lib/vars.sh || exit $?
fx-config-read

if ! command -v jj &> /dev/null; then
  fx-error "jj is not installed. Please install it first (e.g., 'cargo install jj-cli')."
  exit 1
fi

if [[ ! -d "$FUCHSIA_DIR/.jj" ]]; then
  fx-info "Initializing jj in $FUCHSIA_DIR..."
  if ! jj git init --colocate "$FUCHSIA_DIR"; then
    fx-error "Failed to initialize jj in $FUCHSIA_DIR"
    exit 1
  fi
fi

# NOTE: at some point in the future `jj` will be migrating to "Secure Config"
# aka "Configuration that is stored outside of the repository structure"
#
# See: https://docs.jj-vcs.dev/latest/design/secure-config/ for details
#
# As such, assuming the path to the configuration file is
# ${FUCHSIA_DIR}/.jj/repo/config.toml is bound to break at some point.
# When the migration happens there may be some intermittent breakage where
# users may need to re-run this script.
JJ_CONFIG_FILE=$(jj config path --repo)
JJ_CONFIG_DIR=$(dirname JJ_CONFIG_FILE)
mkdir -p "$JJ_CONFIG_DIR"

fx-info "Linking tools/jj/config.toml to $JJ_CONFIG_FILE..."
# Use a relative (-r) symbolic (-s) link so that if FUCHSIA_DIR ever gets
# moved the link doesnt break. Use -f to force creation.
if ! (ln -sfr $FUCHSIA_DIR/tools/jj/config.toml $JJ_CONFIG_FILE); then
  fx-error "Failed to create jj config symlink."
  exit 1
fi

if ! command -v watchman &> /dev/null; then
  fx-warn "Watchman is not installed. It is recommended for better performance with jj."
  fx-warn "See https://facebook.github.io/watchman/docs/install.html for installation instructions."
else
  if [[ ! -f "$FUCHSIA_DIR/.watchmanconfig" ]]; then
    fx-info ".watchmanconfig not found. Running gen-watchman-config..."
    fx-command-run gen-watchman-config || fx-warn "gen-watchman-config failed. jj may be slower as a result."
  fi
fi