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Samuel's questions

Martin Hope
Samuel
Asked: 2024-01-08 18:13:31 +0800 CST
  • 9

大多数时候，powershell 中的错误报告非常有用。我看到了错误，看到了起源，但我注意到 ForEach-Object 管道中的任何错误都会丢失其起源行，并且错误堆栈仅指向带有ForEach-Object.

错误位置示例

Set-StrictMode -Version Latest
$ErrorActionPreference = "Stop"

[cultureinfo]::CurrentUICulture = 'en-US'

function Test-Something($val)
{
    # var is not defined here
    Write-Host($undefined_variable)
}

@("a","b") | ForEach-Object{
    $entry = $_

    Test-Something $entry
}

结果是

ForEach-Object : The variable '$undefined_variable' cannot be retrieved because it has not been set.
In D:\dummy.ps1:12 Line:14
+ @("a","b") | ForEach-Object{
+              ~~~~~~~~~~~~~~~
    + CategoryInfo          : InvalidOperation: (undefined_variable:String) [ForEach-Object], RuntimeException
    + FullyQualifiedErrorId : VariableIsUndefined,Microsoft.PowerShell.Commands.ForEachObjectCommand

该线12指向@("a","b") | ForEach-Object{，这显然不是错误位置。

foreach 的更有用的示例

现在我使用的是foreach（只有最后4行代码发生了变化）

Set-StrictMode -Version Latest
$ErrorActionPreference = "Stop"

[cultureinfo]::CurrentUICulture = 'en-US'

function Test-Something($val)
{
    # var is not defined here
    Write-Host($undefined_variable)
}

$data = @("a","b")

foreach($entry in $data)
{
    Test-Something $entry
}

现在的错误更加有用，它实际上指向错误9行Write-Host($undefined_variable)

The variable '$undefined_variable' cannot be retrieved because it has not been set.
In D:\dummy.ps1:9 Line:16
+     Write-Host($undefined_variable)
+                ~~~~~~~~~~~~~~~~~~~
    + CategoryInfo          : InvalidOperation: (undefined_variable:String) [], ParentContainsErrorRecordException
    + FullyQualifiedErrorId : VariableIsUndefined

这是否与管道运营商的管道性质有关，或者我理解有误。当中间有更多函数时，第一种情况使得错误跟踪变得非常困难。在大多数情况下，我可以切换到foreach，但我很想了解实际发生的情况。

powershell