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Merged
daxian-dbw merged 3 commits into from
Aug 10, 2022
Merged

Do not preserve temporary results when no need to do so #17856

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a2c2a76
Do not preserve temporary results when no need to do so
daxian-dbw Aug 5, 2022
bf82856
Update test
daxian-dbw Aug 5, 2022
46fd8eb
Update src/System.Management.Automation/engine/parser/Compiler.cs
daxian-dbw Aug 8, 2022
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27 changes: 13 additions & 14 deletions src/System.Management.Automation/engine/parser/Compiler.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -2278,26 +2278,25 @@ private Expression CaptureAstResults(
switch (context)
{
case CaptureAstContext.AssignmentWithResultPreservation:
result = Expression.Call(CachedReflectionInfo.PipelineOps_PipelineResult, resultList);

// PipelineResult might get skipped in some circumstances due to an early return or a FlowControlException thrown out, in which case
// we write to the oldPipe. This can happen in cases like:
// $(1;2;return 3)
finallyExprs.Add(Expression.Call(CachedReflectionInfo.PipelineOps_FlushPipe, oldPipe, resultList));
break;
case CaptureAstContext.AssignmentWithoutResultPreservation:
result = Expression.Call(CachedReflectionInfo.PipelineOps_PipelineResult, resultList);

// Clear the temporary pipe in case of exception, if we are not required to preserve the results
if (context == CaptureAstContext.AssignmentWithoutResultPreservation)
var catchExprs = new List<Expression>
{
var catchExprs = new List<Expression>
{
Expression.Call(CachedReflectionInfo.PipelineOps_ClearPipe, resultList),
Expression.Rethrow(),
Expression.Constant(null, typeof(object))
};

catches.Add(Expression.Catch(typeof(RuntimeException), Expression.Block(typeof(object), catchExprs)));
}
Expression.Call(CachedReflectionInfo.PipelineOps_ClearPipe, resultList),
Expression.Rethrow(),
Expression.Constant(null, typeof(object))
};

// PipelineResult might get skipped in some circumstances due to a FlowControlException thrown out, in which case
// we write to the oldPipe. This can happen in cases like:
// $(1;2;return 3)
finallyExprs.Add(Expression.Call(CachedReflectionInfo.PipelineOps_FlushPipe, oldPipe, resultList));
catches.Add(Expression.Catch(typeof(RuntimeException), Expression.Block(typeof(object), catchExprs)));
break;
case CaptureAstContext.Condition:
result = DynamicExpression.Dynamic(PSPipelineResultToBoolBinder.Get(), typeof(bool), resultList);
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22 changes: 22 additions & 0 deletions test/powershell/Language/Scripting/Scripting.Followup.Tests.ps1
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Original file line number Diff line number Diff line change
Expand Up @@ -68,4 +68,26 @@ Describe "Scripting.Followup.Tests" -Tags "CI" {
$result = [ordered]@{ key = 1 }
$result | Should -BeOfType 'System.Collections.Specialized.OrderedDictionary'
}

It "Don't preserve result when no need to do so in case of flow-control exception" {
function TestFunc1([switch]$p) {
## No need to preserve and flush the results from the IF statement to the outer
## pipeline, because the results are supposed to be assigned to a variable.
if ($p) {
$null = if ($true) { "one"; return "two" }
} else {
$a = foreach ($a in 1) { "one"; return; }
}
}

function TestFunc2 {
## The results from the sub-expression need to be preserved and flushed to the outer pipeline.
$("1";return "2")
}

TestFunc1 | Should -Be $null
TestFunc1 -p | Should -Be $null

TestFunc2 | Should -Be @("1", "2")
}
}