Bash脚本中循环遍历后无法向数组bazel_cov_req添加全部元素

编写Bash脚本时，将Git变更的目录路径存入变量后遍历，尝试把包含BUILD.bazel文件的路径添加到数组bazel_cov_req中，但数组仅保留第一个添加的元素，无法完整填充所有匹配路径。

脚本代码：

#!/bin/bash
# set -v -e -o pipefail
bazel_cov_req=() #declared it here for global access.

bazel_coverage_pba() {
#    bazel_cov_req=()
    bbf="BUILD.bazel"
    mr_changed_paths=$(git diff HEAD~1 --name-only | grep -e "src/" | xargs dirname | sort | uniq)
    # echo $mr_changed_paths
    for apath in ${mr_changed_paths[@]}; do
        echo "checking for $apath\n"
        if [ -f "$apath/$bbf" ]; then
            echo "$apath is a bazel path"
            echo "add this path to bazel_coverage_required array"
            bazel_cov_req+=($apath)
            echo "array of paths to be bazel covered\n"
            echo {$bazel_cov_req[@]}
        else
            echo -e "\tbazel build not found under $apath so skip in coverage"
            echo "search a --dir in same path $apath"
            #code here to find file in pre path.
        fi  
    done
   
}

bazel_coverage_pba

运行输出：

checking for src/test/secrets\n
    src/test/secrets is a bazel path
add this path to bazel_coverage_required array
array of paths to be bazel covered\n
{src/test/secrets[@]}
checking for src/test/team\n
    src/test/team is a bazel path
add this path to bazel_coverage_required array
array of paths to be bazel covered\n
{src/test/secrets[@]}
checking for src/ui/automation\n
    bazel build not found under src/ui/automation so skip in coverage
search a --dir in same path src/ui/automation

问题根源 #

1. mr_changed_paths不是数组：用=$(...)将命令结果存入普通字符串变量，而非数组。遍历${mr_changed_paths[@]}时，Bash会把整个字符串按空格拆分，若路径含空格会直接出错，且无法正确遍历每个独立目录。
2. 数组打印语法错误：echo {$bazel_cov_req[@]}是错误写法，Bash不会解析该语法，导致你看到的始终是固定字符串{src/test/secrets[@]}，误以为数组未更新。

修复后的脚本 #

#!/bin/bash
# set -v -e -o pipefail
bazel_cov_req=() # 全局数组

bazel_coverage_pba() {
    bbf="BUILD.bazel"
    # 将命令输出逐行存入数组，支持带空格的路径
    mapfile -t mr_changed_paths < <(git diff HEAD~1 --name-only | grep -e "src/" | xargs dirname | sort | uniq)
    
    for apath in "${mr_changed_paths[@]}"; do
        echo "checking for $apath"
        if [ -f "$apath/$bbf" ]; then
            echo "$apath is a bazel path"
            echo "add this path to bazel_coverage_required array"
            bazel_cov_req+=("$apath")
            echo "array of paths to be bazel covered:"
            echo "${bazel_cov_req[@]}"
        else
            echo -e "\tbazel build not found under $apath so skip in coverage"
            echo "search a --dir in same path $apath"
            # 此处添加上级目录查找逻辑
        fi  
    done
}

bazel_coverage_pba

关键修复点 #

• 用mapfile -t mr_changed_paths < <(...)将命令输出逐行存入数组，确保每个目录是独立的数组元素，兼容带空格的路径。
• 遍历数组时使用"${mr_changed_paths[@]}"，加双引号避免路径被空格拆分。
• 打印数组时使用"${bazel_cov_req[@]}"，正确输出所有数组元素。
• 移除多余的\n，echo默认换行，如需显式换行可使用echo -e。

内容的提问来源于stack exchange，提问作者AhmFM