WiX延迟CustomAction中CustomActionData在ExeCommand取值为空问题排查

我尝试将INSTALLDIR传递给deferred类型的ExeCommand CustomAction，为简化复现仅调用echo [CustomActionData]，代码如下：

<CustomAction Id="SetInstallationDirectory" Property="RunEcho" Value="[INSTALLDIR]" />

<CustomAction Id="SetFoldersFilesToNotWrite"
              Property="CmdPath"
              Value="cmd.exe" />

<CustomAction Id="RunEcho"
              Execute="deferred"
              Impersonate="no"
              Property="CmdPath"
              ExeCommand='/c echo "[CustomActionData]"'
              Return="ignore" />
              
<InstallExecuteSequence>
    <Custom Action="SetInstallationDirectory" After="CostFinalize">NOT Installed</Custom>
    <Custom Action="SetFoldersFilesToNotWrite" After="CostFinalize">NOT Installed</Custom>
    <Custom Action="RunEcho" After="InstallFiles">NOT Installed</Custom>
</InstallExecuteSequence>

运行安装包后，日志显示：

MSI (s) (BC:6C) [19:01:42:524]: PROPERTY CHANGE: Adding RunEcho property. Its value is 'c:\InstallerTest\'.
...
MSI (s) (BC:6C) [19:01:53:213]: Executing op: ActionStart(Name=RunEcho,,)
Action 19:01:53: RunEcho. 
MSI (s) (BC:6C) [19:01:53:214]: Executing op: CustomActionSchedule(Action=RunEcho,ActionType=3186,Source=cmd.exe,Target=/c echo "",CustomActionData=c:\InstallerTest\)
...

可见CustomActionData已经正确获取到目录路径，但ExeCommand却被解析为/c echo ""而非预期的/c echo "c:\InstallerTest\"，请问代码哪里有问题？（使用WiX v3.14.1）

问题原因与解决方案 #

核心问题 #

Deferred类型的ExeCommand CustomAction中，[CustomActionData]的解析逻辑依赖于CustomAction的Property属性必须设置为自身ID。你当前将RunEcho的Property设为CmdPath，导致MSI无法将存储在RunEcho属性中的CustomActionData关联到ExeCommand的变量解析上，最终[CustomActionData]被替换为空字符串。

修正代码 #

调整RunEcho的Property属性为自身ID，并可以简化CmdPath的定义（直接将cmd.exe整合到Source中）：

<CustomAction Id="SetInstallationDirectory" Property="RunEcho" Value="[INSTALLDIR]" />

<CustomAction Id="RunEcho"
              Execute="deferred"
              Impersonate="no"
              Property="RunEcho" <!-- 改为与CustomAction同名的属性 -->
              Source="cmd.exe" <!-- 直接指定程序路径 -->
              ExeCommand='/c echo "[CustomActionData]"'
              Return="ignore" />
              
<InstallExecuteSequence>
    <Custom Action="SetInstallationDirectory" After="CostFinalize">NOT Installed</Custom>
    <Custom Action="RunEcho" After="InstallFiles">NOT Installed</Custom>
</InstallExecuteSequence>

逻辑说明 #

• 当Property属性设置为CustomAction自身ID时，MSI会自动将该属性的值作为CustomActionData，供ExeCommand中的[CustomActionData]变量解析使用。
• 修正后，日志中的Target会变为/c echo "c:\InstallerTest\"，符合预期。

内容的提问来源于stack exchange，提问作者Totem