Yocto使用devtool修改内核编译报KERNEL_LOCALVERSION展开失败

通过devtool modify virtual/kernel创建内核本地工作区后编译内核，触发如下报错，未创建该工作区时编译流程无异常：

ERROR: ExpansionError during parsing /home/aws-fsp-build/rax-workspace/yocto/meta-ti/recipes-kernel/linux/linux-ti-staging-rt_5.10.bb
Traceback (most recent call last):
File "Var <KERNEL_LOCALVERSION>", line 1, in <module>
bb.data_smart.ExpansionError: Failure expanding variable KERNEL_LOCALVERSION, expression was -g${@d.getVar('SRCPV', True).split('+')[1]} which triggered exception IndexError: list index out of range

当前使用meta-ti仓库的dunfell分支，因内核开发需求必须保留本地工作区，完整编译报错日志如下：

Loading cache: 100% |#########################################################################################################| Time: 0:00:00
Loaded 4480 entries from dependency cache.
WARNING: /home/aws-fsp-build/rax-workspace/yocto/meta-ti/recipes-kernel/linux/linux-ti-staging-rt_5.10.bb: Exception during build_dependencies for do_configure
WARNING: /home/aws-fsp-build/rax-workspace/yocto/meta-ti/recipes-kernel/linux/linux-ti-staging-rt_5.10.bb: Error during finalise of /home/aws-fsp-build/rax-workspace/yocto/meta-ti/recipes-kernel/linux/linux-ti-staging-rt_5.10.bb
ERROR: ExpansionError during parsing /home/aws-fsp-build/rax-workspace/yocto/meta-ti/recipes-kernel/linux/linux-ti-staging-rt_5.10.bb
Traceback (most recent call last):
File "Var <KERNEL_LOCALVERSION>", line 1, in <module>
bb.data_smart.ExpansionError: Failure expanding variable KERNEL_LOCALVERSION, expression was -g${@d.getVar('SRCPV', True).split('+')[1]} which triggered exception IndexError: list index out of range

WARNING: /home/aws-fsp-build/rax-workspace/yocto/meta-ti/recipes-kernel/linux/linux-ti-staging-rt_5.4.bb: Cooker received SIGTERM, shutting down...
WARNING: /home/aws-fsp-build/rax-workspace/yocto/meta-carrier/recipes-kernel/linux/linux-ti-staging_4.19.bb: Cooker received SIGTERM, shutting down...
WARNING: /home/aws-fsp-build/rax-workspace/yocto/meta-carrier/recipes-kernel/mstp-mod/mstp-mod.bb: Cooker received SIGTERM, shutting down...

Summary: There were 5 WARNING messages shown.
Summary: There was 1 ERROR message shown, returning a non-zero exit code.

报错来自KERNEL_LOCALVERSION变量的展开逻辑：配方中默认SRCPV变量值包含+分隔符，直接通过split('+')[1]取分割后的第二段内容。
执行devtool modify创建本地工作区后，内核源码源切换为本地目录，SRCPV的值不再包含+字符，分割后返回的列表长度仅为1，访问下标1时直接触发IndexError越界报错。

无需删除本地工作区，任选以下一种方案即可修复：

• 方案1：给KERNEL_LOCALVERSION的取值逻辑增加容错判断，兼容本地源码场景。找到对应内核配方（.bb文件）或自己维护的.bbappend文件中定义KERNEL_LOCALVERSION的行，替换为带判断的写法：

  KERNEL_LOCALVERSION = "-g${@d.getVar('SRCPV', True).split('+')[1] if '+' in d.getVar('SRCPV', True) else ''}"
  

  该写法在远程拉取源码场景下保持原有版本后缀逻辑不变，本地工作区场景下自动追加空后缀，不会触发下标越界，修改后直接重新执行编译即可。
• 方案2：手动指定源码提交哈希，让SRCPV生成时保持原有带+的格式。首先进入本地内核工作区目录，执行命令获取当前提交的短哈希：

  git rev-parse --short HEAD
  

  打开devtool自动生成的对应append配置文件（默认路径为build/workspace/appends/目录下对应linux-ti-staging-rt的.bbappend文件），添加如下配置：

  SRCREV = "<上一步获取到的git提交短哈希>"
  

  保存配置后重新执行编译即可。

内容的提问来源于stack exchange，提问作者Raxesh Oriya