Question

我想了解为什么以下代码打印出来＆＃34;我不应该打印!!＆＃34;

try块中的代码抛出一个错误，因为它的errorAction变量设置为stop，Ppowershell将执行相应的catch块。

在catch测试中，函数调用将失败（因为测试函数param属性validateSet不包含＆＃34; fasdfsd＆＃34;）并抛出明显的非终止异常：ParameterArgumentValidationError

我现在期望在测试函数调用之后执行恢复，打印＆＃34;捕获异常＆＃34;并退出，但它跳出catch块并继续执行打印＆＃34;我不应该打印!!＆＃34;。

我错过了什么？

谢谢，的Davide

function test-function{
[CmdletBinding()]
PARAM(
    [Parameter(Mandatory)]
    [ValidateSet('OnlyAcceptThisStringAndNothingElse')]
    [ValidateNotNullOrEmpty()]
    [string]$param
)
    write-output "Executed"

}

try{
    ## throws an error to enter the catch block
    get-childitem nonexisting -ea stop
}
catch{
    ## test-function does not accept this param and throws an error
    test-function -param "fasdfsd"
    ## this should be executed anyway but it isn't
    write-output "caught exception"
    ## the script should quit here
    exit
}
## this Should not have been executed but it is
write-output "I shouldn't be printed!!"

Answer 1

@beatcracker 如果一切正常，那么在非。之后终止异常，执行应继续下一步写入输出的指令＆＃34;捕获异常＆＃34;不久之后命令＆＃34;退出＆＃34;哪个应该退出剧本。

- Davide Talesco

我同意，我对此并不清楚。我的意思是它始终以这种方式工作 - 必须将catch块中的所有内容包装到另一个try / catch中，否则它将在非终止错误时默默地退出catch scriptblock并继续执行下一个代码。

<小时/> 下面不是一个真正的答案，只是一个希望的蠢货，一个更熟练的人可以理解它。 虽然我无法理解为什么会这样做，但我认为我已将其本地化为System.Management.Automation汇编（public class ScriptBlock）中的代码：

internal void InvokeWithPipe(bool useLocalScope, bool writeErrors, object dollarUnder, object input, object scriptThis, Pipe outputPipe, ref ArrayList resultList, params object[] args)
{
    ExecutionContext contextFromTLS = this.GetContextFromTLS();
    if (contextFromTLS.CurrentPipelineStopping)
    {
        throw new PipelineStoppedException();
    }
    ParseTreeNode codeToInvoke = this.GetCodeToInvoke();
    if (codeToInvoke != null)
    {
        InvocationInfo invocationInfo = new InvocationInfo(null, codeToInvoke.NodeToken, contextFromTLS);
        contextFromTLS.Debugger.PushMethodCall(invocationInfo, this);
        bool flag = false;
        ScriptInvocationContext oldScriptContext = null;
        Pipe shellFunctionErrorOutputPipe = null;
        CommandOrigin scopeOrigin = contextFromTLS.EngineSessionState.currentScope.ScopeOrigin;
        Exception exception = null;
        SessionStateInternal engineSessionState = contextFromTLS.EngineSessionState;
        ActivationRecord oldActivationRecord = null;
        try
        {
            ScriptInvocationContext scriptContext = new ScriptInvocationContext(useLocalScope, scriptThis, dollarUnder, input, args);
            this.EnterScope(contextFromTLS, scriptContext, out oldScriptContext, out oldActivationRecord);
            shellFunctionErrorOutputPipe = contextFromTLS.ShellFunctionErrorOutputPipe;
            if (!writeErrors)
            {
                contextFromTLS.ShellFunctionErrorOutputPipe = null;
            }
            contextFromTLS.EngineSessionState.currentScope.ScopeOrigin = CommandOrigin.Internal;
            if (!string.IsNullOrEmpty(this.File))
            {
                contextFromTLS.Debugger.PushRunning(this.File, this, false);
                flag = true;
            }
            codeToInvoke.Execute(null, outputPipe, ref resultList, contextFromTLS);
        }
        catch (ReturnException exception2)
        {
            if (!this._isScriptBlockForExceptionHandler)
            {
                ParseTreeNode.AppendResult(contextFromTLS, exception2.Argument, null, ref resultList);
            }
            else
            {
                exception = exception2;
            }
        }
        finally
        {
            if (flag)
            {
                contextFromTLS.Debugger.PopRunning();
            }
            contextFromTLS.ShellFunctionErrorOutputPipe = shellFunctionErrorOutputPipe;
            contextFromTLS.EngineSessionState.currentScope.ScopeOrigin = scopeOrigin;
            try
            {
                this.LeaveScope(contextFromTLS, oldScriptContext, engineSessionState, oldActivationRecord);
            }
            finally
            {
                contextFromTLS.Debugger.PopMethodCall();
            }
        }
        if (exception != null)
        {
            throw exception;
        }
    }
}

catch的Scriptblocks是通过内部密封的_isScriptBlockForExceptionHandler方法true将ExceptionHandlerNode设置为Invoke创建的，该方法从上述方法调用CreateExceptionHandler公共课ScriptBlock：

internal static ScriptBlock CreateExceptionHandler(ParseTreeNode body, Token token, int pipelineSlots, int variableSlots)
{
    return new ScriptBlock(token, null, null, null, null, body, null, false, null, null, null, pipelineSlots, variableSlots) { _isScriptBlockForExceptionHandler = true };
}

请注意，当_isScriptBlockForExceptionHandler设置为true时，如果发生异常，则在上面的InvokeWithPipe方法中执行catch块时不会抛出异常：

catch (ReturnException exception2)
{
    if (!this._isScriptBlockForExceptionHandler)
    {
        ParseTreeNode.AppendResult(contextFromTLS, exception2.Argument, null, ref resultList);
    }
    else
    {
        exception = exception2;
    }
}

AppendResult方法的作用对我来说并不清楚，但我发现this：

调用AppendResult方法基本上调用了getter 返回的对象的公共属性检索值将被写入输出控制台。

catch块中的Powershell异常会导致意外的执行流程

1 个答案: