切换Git分支后Docker容器内Composer install因Git缺失失败

报错信息 #

git was not found in your PATH, skipping source download now trying to download from dist In GitDownloader.php line 246: Failed to execute git show-ref --head -d sh: 1: git: not found

问题触发步骤 #

• 使用git checkout <branch_name>切换Git分支；
• 通过docker exec -it <container_id> bash进入Docker容器；
• 在容器内执行composer install。

切换分支后容器内无法找到Git可执行文件，导致composer install失败。

docker-compose.yml配置 #

version: "3.7"

networks:
  app-network:
    name: app-network

volumes:
  dbdata:
    driver: local
  dbdatatesting:
    driver: local

services:
  composer:
    image: composer/composer
    working_dir: /var/www/html
    volumes:
      - "${APP_PATH_HOST:-./}:/var/www/html"
    networks:
      - app-network

  database:
    image: mysql:5.7
    container_name: database
    ports:
      - ${FORWARD_DB_PORT:-3306}:3306
    environment:
      MYSQL_DATABASE: project
      MYSQL_USER: homestead
      MYSQL_PASSWORD: 123456
      MYSQL_ROOT_PASSWORD: 123456
      SERVICE_NAME: mysql
    volumes:
      - dbdata:/var/lib/mysql
      - .docker/database/entrypoint/:/docker-entrypoint-initdb.d
    networks:
      - app-network

  db:
    image: mysql:5.7
    container_name: database_testing
    ports:
      - ${FORWARD_DB_PORT_TESTING:-33071}:33071
    environment:
      MYSQL_DATABASE: project_testing
      MYSQL_USER: homestead
      MYSQL_PASSWORD: 123456
      MYSQL_ROOT_PASSWORD: 123456
      SERVICE_NAME: mysql
    volumes:
      - dbdatatesting:/var/lib/mysql
    networks:
      - app-network

  mailhog:
    image: mailhog/mailhog
    ports:
      - "1025:1025"
      - "8025:8025"
    networks:
      - app-network

  node:
    image: "node:8"
    user: "${USER_MAPPING:-node}"
    working_dir: /var/www/html
    environment:
      - NODE_ENV=development
    volumes:
      - ${APP_PATH_HOST:-./}:/var/www/html
    expose:
      - "8081"

  nginx:
    image: nginx:alpine
    volumes:
      - ${APP_PATH_HOST:-./}:/var/www/html
      - .docker/nginx/default:/etc/nginx/conf.d/default.conf
      - ./localhost.crt:/etc/ssl/certs/localhost.crt
      - ./localhost.key:/etc/ssl/private/localhost.key
    ports:
      - "${HOST_HTTP_PORT:-80}:80"
      - "443:443"
    depends_on:
      - php-fpm
    networks:
      - app-network

  php-fpm:
    image: registry.gitlab.com/myfolder/testproject/bc-php7.4-debug:latest
    user: "${USER_MAPPING:-1000:1000}"
    working_dir: /var/www/html
    volumes:
      - ${APP_PATH_HOST:-./}:/var/www/html
    networks:
      - app-network
    depends_on:
      - database
      - redis

  redis:
    image: redis:5.0.9
    container_name: redis
    ports:
      - "6379:6379"
    networks:
      - app-network

环境详情 #

• 操作系统：Windows子系统Linux
• Docker版本：20.10.21, build baeda1f
• Docker容器内Composer版本：2.3.5

需求：无需卸载Docker或删除容器，需继续工作。

已尝试的排查方法 #

• 重启Docker，问题仍存在；
• 尝试安装Git，但容器内仍无法找到Git；
• 使用最新镜像重建Docker容器，问题依旧。

解决建议 #

1. 直接使用Composer容器执行命令 #

你的docker-compose.yml已定义composer服务，官方镜像自带Git，无需进入php-fpm容器，直接在宿主机运行：

docker-compose run --rm composer install

2. 在php-fpm容器内临时安装Git #

进入容器后，根据镜像系统执行安装命令：

• Debian/Ubuntu系镜像：

  apt update && apt install -y git
  

• Alpine系镜像：

  apk add --no-cache git
  

若安装后仍找不到Git，检查PATH环境变量：

echo $PATH

确认Git安装路径（通常为/usr/bin/git）是否在PATH中，若不在则临时添加：

export PATH=$PATH:/usr/bin

3. 强制Composer使用dist下载源 #

暂时无法安装Git时，可跳过Git操作，直接下载预编译包：

composer install --prefer-dist

4. 永久修改php-fpm镜像 #

若需长期解决，修改自定义php镜像的Dockerfile，添加Git安装步骤：

• Debian/Ubuntu系：

  RUN apt update && apt install -y git && rm -rf /var/lib/apt/lists/*
  

• Alpine系：

  RUN apk add --no-cache git
  

重新构建并推送镜像，后续启动容器将自带Git。

内容的提问来源于stack exchange，提问作者Dev Mil