catch块中的Powershell异常导致意外的执行流

Question

我试图理解为什么下面的代码打印“我不应该被打印！!"

try块中的代码抛出一个错误，当它的errorAction变量被设置为stop时，Ppowershell将执行相应的catch块。

在catch中，测试函数调用将失败（因为测试函数参数属性validateSet不包括“facdfsd”）并抛出明显不终止的异常：ParameterArgumentValidationError

我现在期望执行在测试函数调用后继续在该行，打印“捕获异常”并退出，但它跳出捕获块并继续执行打印“我不应该打印！！”。

我错过了什么？

谢谢，大卫

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如果在非终止异常之后一切正常，则执行应继续执行下一条指令，即写入输出“捕获异常”，并在命令“退出”后不久退出脚本。

-大卫·塔莱斯科

我同意，我不清楚这一点。我的意思是，它总是以这种方式工作 - 必须将捕获块内的所有内容包装到另一个尝试/捕获中，否则它只会在非终止错误时默默地退出捕获脚本块并继续执行接下来出现的任何代码。

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的脚本块由内部密封类< code > exception handler node 的方法< code>Invoke在< code > _ isScriptBlockForExceptionHandler 设置为< code>true的情况下创建，该方法从前面提到的公共类< code>ScriptBlock中调用< code > CreateExceptionHandler :

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＜code＞_ISScript BlockForExceptionHandler

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

我不清楚AppendResult方法做了什么，但我发现：

调用AppendResult方法主要是从返回的对象中调用公共属性的getters，以检索将被写入输出控制台的值。