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Handle null reference exception in CsvCommands.cs: ConvertPSObjectToCSV #26144

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Merged
iSazonov merged 2 commits into from
Oct 16, 2025
Merged

Handle null reference exception in CsvCommands.cs: ConvertPSObjectToCSV #26144

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0364889
Fix issue #25836
mikkas456 Oct 3, 2025
4f3a6f5
Simplify null check, remove unnecessary test
mikkas456 Oct 3, 2025
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10 changes: 9 additions & 1 deletion src/Microsoft.PowerShell.Commands.Utility/commands/utility/CsvCommands.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -1044,7 +1044,15 @@ internal string ConvertPSObjectToCSV(PSObject mshObject, IList<string> propertyN
{
if (dictionary.Contains(propertyName))
{
value = dictionary[propertyName].ToString();
//Handle null reference exception for existing property with null value
if (dictionary[propertyName] == null)
{
value = null;
}
else
{
value = dictionary[propertyName].ToString();
}
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@iSazonov iSazonov Oct 3, 2025

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Can we simplify the code?

Suggested change
//Handle null reference exception for existing property with null value
if (dictionary[propertyName] == null)
{
value = null;
}
else
{
value = dictionary[propertyName].ToString();
}
value = dictionary[propertyName]?.ToString();

Also please remove obvious comment.

}
else if (mshObject.Properties[propertyName] is PSPropertyInfo property)
{
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12 changes: 12 additions & 0 deletions test/powershell/Modules/Microsoft.PowerShell.Utility/ConvertTo-Csv.Tests.ps1
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Expand Up @@ -212,6 +212,7 @@ Describe "ConvertTo-Csv" -Tags "CI" {
[ordered]@{ Number = $_; Letter = $Letters[$_] }
}
$CsvString = $Items | ConvertTo-Csv
$TestHashTable = [ordered]@{ 'first' = 'value1'; 'second' = $null; 'third' = 'value3' }
}

It 'should treat dictionary entries as properties' {
Expand All @@ -235,5 +236,16 @@ Describe "ConvertTo-Csv" -Tags "CI" {
$NewCsvString[0] | Should -MatchExactly 'Extra'
$NewCsvString | Select-Object -Skip 1 | Should -MatchExactly 'Surprise!'
}

It 'should convert hashtable with null values without error'{
{ $TestHashTable | ConvertTo-Csv } | Should -Not -Throw
}

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@iSazonov iSazonov Oct 3, 2025

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We can remove the test since next one does the check.

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@mikkas456 mikkas456 Oct 3, 2025

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Alright, I have addressed these issues in another commit.

It 'should properly convert hashtable with null and non-null values'{
$CsvResult = $TestHashTable | ConvertTo-Csv

$CsvResult[0] | Should -BeExactly "`"first`",`"second`",`"third`""
$CsvResult[1] | Should -BeExactly "`"value1`",$null,`"value3`""
}
}
}
28 changes: 28 additions & 0 deletions test/powershell/Modules/Microsoft.PowerShell.Utility/Export-Csv.Tests.ps1
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Expand Up @@ -11,6 +11,7 @@ Describe "Export-Csv" -Tags "CI" {
$P1 = [pscustomobject]@{"P1" = "first"}
$P2 = [pscustomobject]@{"P2" = "second"}
$P11 = [pscustomobject]@{"P1" = "eleventh"}
$testHashTable = @{ 'first' = "value1"; 'second' = $null; 'third' = "value3" }
}

AfterEach {
Expand Down Expand Up @@ -249,6 +250,33 @@ Describe "Export-Csv" -Tags "CI" {
$contents[1].Contains($delimiter) | Should -BeTrue
}

It "Should not throw when exporting hashtable with property that has null value"{
{ $testHashTable | Export-Csv -Path $testCsv } | Should -Not -Throw
}

It "Should not throw when exporting PSCustomObject with property that has null value"{
$testObject = [pscustomobject]$testHashTable
{ $testObject | Export-Csv -Path $testCsv } | Should -Not -Throw
}

It "Export hashtable with null and non-null values"{
$testHashTable | Export-Csv -Path $testCsv
$result2 = Import-CSV -Path $testCsv

$result2.first | Should -BeExactly "value1"
$result2.second | Should -BeNullOrEmpty
$result2.third | Should -BeExactly "value3"
}

It "Export hashtable with non-null values"{
$testTable = @{ 'first' = "value1"; 'second' = "value2" }
$testTable | Export-Csv -Path $testCsv
$results = Import-CSV -Path $testCsv

$results.first | Should -BeExactly "value1"
$results.second | Should -BeExactly "value2"
}

Context "UseQuotes parameter" {

# A minimum of tests. The rest are in ConvertTo-Csv.Tests.ps1
Expand Down