Revert the PR "Make ForEach-Object faster for its commonly used scenarios" (PowerShell#10485)

It turns out this optimization brings in a breaking change: `$MyInvocation` is different comparing to before the optimization change. I tried to fix the breaking change, but couldn't without introducing more hacky code. Given that, that PR should be reverted.

Author: daxian-dbw

src/System.Management.Automation/engine/runtime/Operations/MiscOps.cs

@@ -68,7 +68,7 @@ private static CommandProcessorBase AddCommand(PipelineProcessor pipe,
 
             object command;
             IScriptExtent commandExtent;
-            var cpiCommand = commandElements[commandIndex++];
+            var cpiCommand = commandElements[commandIndex];
             if (cpiCommand.ParameterNameSpecified)
             {
                 command = cpiCommand.ParameterText;
@@ -156,16 +156,12 @@ private static CommandProcessorBase AddCommand(PipelineProcessor pipe,
                 }
             }
 
-            // If possible, rewrite the 'ForEach-Object' command into a filter-like script block in the pipeline.
-            //   e.g. 1..2 | ForEach-Object { $_ + 1 }  =>  1..2 | . { process { $_ + 1 } }
-            if (!TryRewriteForEachObjectCommand(context, commandSessionState, commandElements, ref commandProcessor, ref commandIndex))
-            {
-                InternalCommand cmd = commandProcessor.Command;
-                commandProcessor.UseLocalScope = !dotSource && (cmd is ScriptCommand || cmd is PSScriptCmdlet);
-            }
+            InternalCommand cmd = commandProcessor.Command;
+            commandProcessor.UseLocalScope = !dotSource &&
+                                             (cmd is ScriptCommand || cmd is PSScriptCmdlet);
 
             bool isNativeCommand = commandProcessor is NativeCommandProcessor;
-            for (int i = commandIndex; i < commandElements.Length; ++i)
+            for (int i = commandIndex + 1; i < commandElements.Length; ++i)
             {
                 var cpi = commandElements[i];
 
@@ -315,107 +311,6 @@ private static CommandProcessorBase AddCommand(PipelineProcessor pipe,
             return commandProcessor;
         }
 
-        private static ConditionalWeakTable<ScriptBlockAst, ScriptBlock> s_astRewriteCache = new ConditionalWeakTable<ScriptBlockAst, ScriptBlock>();
-        private static ConditionalWeakTable<ScriptBlockAst, ScriptBlock>.CreateValueCallback s_astRewriteCallback =
-            sbAst =>
-            {
-                ScriptBlockAst newScriptBlockAst = new ScriptBlockAst(
-                    sbAst.Extent,
-                    paramBlock: null,
-                    beginBlock: null,
-                    processBlock: (NamedBlockAst)sbAst.EndBlock.Copy(),
-                    endBlock: null,
-                    dynamicParamBlock: null);
-                newScriptBlockAst.PostParseChecksPerformed = sbAst.PostParseChecksPerformed;
-                sbAst.Parent?.SetParent(newScriptBlockAst);
-
-                return new ScriptBlock(newScriptBlockAst, isFilter: false);
-            };
-
-        private static bool TryRewriteForEachObjectCommand(
-            ExecutionContext context,
-            SessionStateInternal commandSessionState,
-            CommandParameterInternal[] commandElements,
-            ref CommandProcessorBase commandProcessor,
-            ref int commandIndex)
-        {
-            const string ForEachObject_ProcessParam = "Process";
-
-            // Skip optimization in the following cases
-            //  1. the debugger is enabled -- so a breakpoint set on the command 'ForEach-Object' works properly.
-            //  2. the 'ConstrainedLanguageMode' has been used for the current runspace -- the language mode transition is tricky,
-            //     and it's better to use the same old code path for safety.
-            if (context._debuggingMode > 0 || context.HasRunspaceEverUsedConstrainedLanguageMode)
-            {
-                return false;
-            }
-
-            var cmdlet = commandProcessor.CommandInfo as CmdletInfo;
-            if (cmdlet == null || cmdlet.ImplementingType != typeof(ForEachObjectCommand))
-            {
-                return false;
-            }
-
-            int indexAdvanceOffset = 0;
-            int cmdElementsLength = commandElements.Length;
-            ScriptBlock processScriptBlock = null;
-
-            if (commandIndex == cmdElementsLength - 1)
-            {
-                // Target ForEach-Object syntax:
-                //  * `... | ForEach-Object { ... } | ...`
-                //  * `... | ForEach-Object -process:{ ... } | ...`
-                var currentElement = commandElements[commandIndex];
-                if (currentElement.ArgumentSpecified && !currentElement.ArgumentSplatted &&
-                    (!currentElement.ParameterAndArgumentSpecified || ForEachObject_ProcessParam.Equals(currentElement.ParameterName, StringComparison.OrdinalIgnoreCase)))
-                {
-                    processScriptBlock = currentElement.ArgumentValue as ScriptBlock;
-                    indexAdvanceOffset = 1;
-                }
-            }
-            else if (commandIndex == cmdElementsLength - 2)
-            {
-                // Target ForEach-Object syntax:
-                //  * `... | ForEach-Object -Process { ... } | ...`
-                var currentElement = commandElements[commandIndex];
-                var nextElement = commandElements[commandIndex + 1];
-
-                if (currentElement.ParameterNameSpecified && !currentElement.ArgumentSpecified &&
-                    ForEachObject_ProcessParam.Equals(currentElement.ParameterName, StringComparison.OrdinalIgnoreCase) &&
-                    nextElement.ArgumentSpecified && !nextElement.ArgumentSplatted && !nextElement.ParameterNameSpecified)
-                {
-                    processScriptBlock = nextElement.ArgumentValue as ScriptBlock;
-                    indexAdvanceOffset = 2;
-                }
-            }
-
-            if (processScriptBlock != null && processScriptBlock.Ast is ScriptBlockAst sbAst)
-            {
-                if (!sbAst.IsConfiguration && sbAst.ParamBlock == null && sbAst.BeginBlock == null &&
-                    sbAst.ProcessBlock == null && sbAst.DynamicParamBlock == null && sbAst.EndBlock != null &&
-                    sbAst.EndBlock.Unnamed)
-                {
-                    ScriptBlock sbRewritten = s_astRewriteCache.GetValue(sbAst, s_astRewriteCallback);
-                    ScriptBlock sbToUse = sbRewritten.Clone();
-                    sbToUse.SessionStateInternal = processScriptBlock.SessionStateInternal;
-                    sbToUse.LanguageMode = processScriptBlock.LanguageMode;
-
-                    // We always clone the script block, so that the cached value doesn't hold on to any session state.
-                    // Foreach-Object invokes the script block in the caller's scope, so do not use new scope.
-                    commandProcessor = CommandDiscovery.CreateCommandProcessorForScript(
-                        sbToUse,
-                        context,
-                        useNewScope: false,
-                        commandSessionState);
-
-                    commandIndex += indexAdvanceOffset;
-                    return true;
-                }
-            }
-
-            return false;
-        }
-
         internal static IEnumerable<CommandParameterInternal> Splat(object splattedValue, Ast splatAst)
         {
             splattedValue = PSObject.Base(splattedValue);

test/powershell/Modules/Microsoft.PowerShell.Core/ForEach-Object.Tests.ps1

@@ -41,4 +41,10 @@ Describe "ForEach-Object" -Tags "CI" {
         $sbToUse = GetScriptBlock
         1 | ForEach-Object $sbToUse | Should -BeExactly "ForEachObjectTest-Zoo"
     }
+
+    It "ForEach-Object scriptblock should get the 'InvocationInfo' from the caller scope" {
+        $file = New-Item TestDrive:\test.ps1 -ItemType File -Force
+        Set-Content -Path $file -Value '1 | ForEach-Object { $MyInvocation.MyCommand.Name }'
+        TestDrive:\test.ps1 | Should -BeExactly "test.ps1"
+    }
 }