scripts/cog/git-polyfill/git

#!/bin/bash
# Copyright 2025 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.

set -o errexit

readonly SCRIPTS_COG_BIN_DIR="$(cd "$(dirname "${BASH_SOURCE[0]}")" >/dev/null 2>&1 && pwd)"
readonly PY_TOOL="${SCRIPTS_COG_BIN_DIR}/../../fuchsia-vendored-python"
readonly REPO_ROOT="$(realpath ${SCRIPTS_COG_BIN_DIR}/../../..)"

# This script acts as a wrapper around the system 'git' command.
# However, the underlying Python script (git.py) may still need to invoke the
# actual 'git' binary (e.g., for 'git citc' commands).
#
# We need to explicitly locate and pass the path to the real 'git' binary
# because 'fuchsia-vendored-python' executes within a hermetic environment
# that strips out most environment variables. This prevents us from simply
# passing the location via an environment variable like FUCHSIA_REAL_GIT.
function find_real_git() {
    local cmd_name
    cmd_name=$(basename "$0")
    local current_script_path
    current_script_path=$(realpath "$0")

    for candidate in $(which -a "$cmd_name"); do
        local candidate_resolved
        candidate_resolved=$(realpath "$candidate")
        if [ "$candidate_resolved" != "$current_script_path" ]; then
            echo "$candidate"
            return 0
        fi
    done
    return 1
}

function main() {
    local real_git
    if ! real_git=$(find_real_git); then
        echo "Error: Could not find real git binary." >&2
        exit 1
    fi

    local log_args=()
    if [[ -n "${FUCHSIA_LOG_GIT_POLYFILL_COMMANDS}" ]]; then
        log_args+=(--log-file "${FUCHSIA_LOG_GIT_POLYFILL_COMMANDS}")
    fi

    # We need to run this script from within the fuchsia directory or else the hermetic-env will not work.
    # This is because we might be running this from the build directory which is symlinked to the
    # fuchsia directory and the hermetic-env will not work if we are not in the fuchsia directory.
    # We could run this from the FUCHSIA_DIR but this might not be set and we want to ensure that we
    # are using a variable that is set so we run it in the scripts/cog/bin directory.
    exec env -C "${SCRIPTS_COG_BIN_DIR}" "$PY_TOOL" "git.py" \
        "${log_args[@]}" \
        --invoker-cwd "$(pwd)" \
        --real-git "${real_git}" \
        --repository-root "${REPO_ROOT}" \
        -- "$@"
}

main "$@"