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Fix casting single element array to generic collection #3170

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Merged
daxian-dbw merged 6 commits into from
Feb 23, 2017
Merged

Fix casting single element array to generic collection #3170

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658883a
Fix casting single element array to generic collection
daxian-dbw Feb 19, 2017
b8cf316
Fix comments in tests
daxian-dbw Feb 20, 2017
7531634
Fix the test a bit more
daxian-dbw Feb 20, 2017
8d0907c
One more fix in the test
daxian-dbw Feb 21, 2017
eed79d1
add test for casting array with more than 1 string elements
daxian-dbw Feb 22, 2017
d058513
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daxian-dbw Feb 22, 2017
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12 changes: 6 additions & 6 deletions src/System.Management.Automation/engine/LanguagePrimitives.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -3581,20 +3581,20 @@ internal object Convert(object valueToConvert,
TypeTable backupTable)
{
IList resultAsList = null;
int listSize = 0;
Array array = null;

try
{
// typeof(Array).IsAssignableFrom(typeof(object[])) == true
if ((IsScalar) || (!(valueToConvert is Array)))
int listSize = 0;
if (IsScalar)
{
listSize = 1;
}
else
{
array = (Array)valueToConvert;
listSize = array.Length;
// typeof(Array).IsAssignableFrom(typeof(object[])) == true
array = valueToConvert as Array;
listSize = array != null ? array.Length : 1;
}

resultAsList = ListCtorLambda(listSize);
Expand All @@ -3610,7 +3610,7 @@ internal object Convert(object valueToConvert,
{
resultAsList.Add(valueToConvert);
}
else if (listSize == 1)
else if (array == null)
{
object convertedValue = LanguagePrimitives.ConvertTo(valueToConvert, ElementType, formatProvider);
resultAsList.Add(convertedValue);
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52 changes: 52 additions & 0 deletions test/powershell/Language/Parser/Conversions.Tests.ps1
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Original file line number Diff line number Diff line change
Expand Up @@ -20,4 +20,56 @@ Describe 'conversion syntax' -Tags "CI" {
# This test relies on the fact that there are overloads (at least 2) for ToString method.
([System.Management.Automation.ActionPreference]"Stop").ToString() | Should Be "Stop"
}

Context "Cast object[] to more narrow generic collection" {
BeforeAll {
$testCases1 = @(
## It's intentional to have 'Command' to be `{$result = ...}` and run it with `. $Command`.
## This is because `$result = & {[List[int]]@(1,2)}` will cause the resulted List to be unraveled,
## and in that case `$result` would be just an object array.
## To prevent unraveling, Command needs to be `{, [List[int]]@(1,2)}`, but then the test case title
## would become `, [List[int]]@(1,2)`, which is more confusing than `$result = [List[int]]@(1,2)`.
## This is why the current form of `$result = [List[int]]@(1,2)` is used intentionally here.

@{ Command = {$result = [Collections.Generic.List[int]]@(1)}; CollectionType = 'List`1'; ElementType = "Int32"; Elements = @(1) }
@{ Command = {$result = [Collections.Generic.List[int]]@(1,2)}; CollectionType = 'List`1'; ElementType = "Int32"; Elements = @(1,2) }
@{ Command = {$result = [Collections.Generic.List[int]]"4"}; CollectionType = 'List`1'; ElementType = "Int32"; Elements = @(4) }
@{ Command = {$result = [Collections.Generic.List[int]]@("4","5")}; CollectionType = 'List`1'; ElementType = "Int32"; Elements = @(4,5) }

@{ Command = {$result = [Collections.Generic.List[string]]@(1)}; CollectionType = 'List`1'; ElementType = "String"; Elements = @("1") }
@{ Command = {$result = [Collections.Generic.List[string]]@(1,2)}; CollectionType = 'List`1'; ElementType = "String"; Elements = @("1","2") }
@{ Command = {$result = [Collections.Generic.List[string]]1}; CollectionType = 'List`1'; ElementType = "String"; Elements = @("1") }
@{ Command = {$result = [Collections.Generic.List[string]]@("4")}; CollectionType = 'List`1'; ElementType = "String"; Elements = @("4") }

@{ Command = {$result = [System.Collections.ObjectModel.Collection[int]]@(1)}; CollectionType = 'Collection`1'; ElementType = "Int32"; Elements = @(1) }
@{ Command = {$result = [System.Collections.ObjectModel.Collection[int]]@(1,2)}; CollectionType = 'Collection`1'; ElementType = "Int32"; Elements = @(1,2) }
@{ Command = {$result = [System.Collections.ObjectModel.Collection[int]]"4"}; CollectionType = 'Collection`1'; ElementType = "Int32"; Elements = @(4) }
@{ Command = {$result = [System.Collections.ObjectModel.Collection[int]]@("4","5")}; CollectionType = 'Collection`1'; ElementType = "Int32"; Elements = @(4,5) }

@{ Command = {$result = [Collections.Generic.List[System.IO.FileInfo]]@('TestFile')};
CollectionType = 'List`1'; ElementType = "FileInfo"; Elements = @('TestFile') }
@{ Command = {$result = [Collections.Generic.List[System.IO.FileInfo]]@('TestFile1', 'TestFile2')};
CollectionType = 'List`1'; ElementType = "FileInfo"; Elements = @('TestFile1', 'TestFile2') }
@{ Command = {$result = [Collections.Generic.List[System.IO.FileInfo]]'TestFile'};
CollectionType = 'List`1'; ElementType = "FileInfo"; Elements = @('TestFile') }
)
}

It "<Command>" -TestCases $testCases1 {
param($Command, $CollectionType, $ElementType, $Elements)

$result = $null
. $Command
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@lzybkr lzybkr Feb 22, 2017

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It would be less surprising to me if Command was just a script block and here you wrote:

$result = . $Command

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@daxian-dbw daxian-dbw Feb 22, 2017

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The resulted collection will be unraveled if I use $result = . {[Collections.Generic.List[int]]@(1)}.

In order to prevent unraveling, a comma needs to be prefixed like "{,[Collections.Generic.List[int]]@(1)}".
But then the test case title becomes ",[Collections.Generic.List[int]]@(1)" which I thought was more confusing than "$result = [Collections.Generic.List[int]]@(1)" and that's why I choose the current form.
Do you want me to change back to {, [Collections.Generic.List[int]]@(1)}?

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@lzybkr lzybkr Feb 22, 2017

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I see - neither is great - I'm fine either way then.
Because you tried what I suggested first - maybe it's worth a comment to save someone else the trouble trying to change it.

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@daxian-dbw daxian-dbw Feb 22, 2017

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Got it. Will add a comment.

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@daxian-dbw daxian-dbw Feb 22, 2017

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Comment added.


$result | Should Not BeNullOrEmpty
$result.GetType().Name | Should Be $CollectionType

$genericArgs = $result.GetType().GetGenericArguments()
$genericArgs.Length | Should Be 1
$genericArgs[0].Name | Should Be $ElementType

$result.Count | Should Be $Elements.Length
$result -join ";" | Should Be ($Elements -join ";")
}
}
}