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GetNetworkCredential() returns null if PSCredential has null or empty user name #4697

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Merged
TravisEz13 merged 2 commits into from
Sep 1, 2017
Merged

GetNetworkCredential() returns null if PSCredential has null or empty user name #4697

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a82738b
GetNetworkCredential() returns null if PSCredential has empty user name
iSazonov Aug 29, 2017
979ff8e
Fix test
iSazonov Aug 31, 2017
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6 changes: 6 additions & 0 deletions src/System.Management.Automation/engine/Credential.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -330,6 +330,12 @@ private static bool IsValidUserName(string input,
out string user,
out string domain)
{
if (String.IsNullOrEmpty(input))
{
user = domain = null;
return false;
}

SplitUserDomain(input, out user, out domain);

if ((user == null) ||
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6 changes: 6 additions & 0 deletions test/powershell/engine/Basic/Credential.Tests.ps1
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@@ -0,0 +1,6 @@
Describe "Credential tests" -Tags "CI" {
It "Explicit cast for an empty credential returns null" {
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@TravisEz13 TravisEz13 Aug 30, 2017

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Should we add a case for an empty username? How do you get the password from the object if GetNetworkCredential returns $null

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@iSazonov iSazonov Aug 31, 2017

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PSCredential constructor fails if username is empty. The only way to get an empty credentials is [PSCredential]::Empty. And if we can [PSCredential]::Empty any methods shouldn't throw for the empty credential - we're just fix the issue.

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@daxian-dbw daxian-dbw Aug 31, 2017

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Actually, you are able to create empty PSCredential instances with a public constructor PSCredential(psobject pso)

$psobj = [pscustomobject] @{}
$cred = [pscredential]::new($psobj)

The current implementation of GetNetworkCredential() doesn't allow returning a null value -- it throws if the user name is invalid. I think we should keep it that way and throw exception when user name is null or empty.

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@iSazonov iSazonov Aug 31, 2017

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Why we allow the sample? It seems constructor should throw in the case.
On the other hand, [PSCredential]::Empty is a valid object - why any its method should throw?

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@daxian-dbw daxian-dbw Aug 31, 2017

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Why we allow the sample?

Do you mean the XML comment? I missed the comment, and it looks totally fine to return null then :)

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@iSazonov iSazonov Aug 31, 2017

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I meant your sample:

$psobj = [pscustomobject] @{}
$cred = [pscredential]::new($psobj)

Why the constructor don't throw? It seems the constructor should throw.

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@daxian-dbw daxian-dbw Aug 31, 2017

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I don't know the original intention, but changing this behavior would be a breaking change for sure -- it makes something that works stop working. It feels insignificant to me, so I don't think it's worth to be fixed. But you can go both ways -- it's insignificant so a breaking change might not matter.

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@iSazonov iSazonov Aug 31, 2017

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For the PR I think we can leave the constructor as is.

Please clarify what is your conclusion about the PR fix?

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@daxian-dbw daxian-dbw Aug 31, 2017

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Based on the existing XML comments for GetNetworkCredential(), I withdraw my comment about making GetNetworkCredential throw. Returning null is totally fine.

# We should explicitly check that the expression returns $null
[PSCredential]::Empty.GetNetworkCredential() | Should Be $null
}
}