Can´t create TAG specification for EC2 instance

[PetrMa]

Describe the bug

I have AWS.Tools 5.0.17 installed on Windows computer

this script:
Import-Module -Name AWS.Tools.EC2
$tag = New-Object Amazon.EC2.Model.Tag
$tag.Key = "Name"
$tag.Value = "MyEC2Instance"
$tagSpec = New-Object Amazon.EC2.Model.TagSpecification
$tagSpec.ResourceType = "instance"
$tagSpec.Tags.Add($tag)

ends with an error:
InvalidOperation: You cannot call a method on a null-valued expression.

In version 4.1.xxx it works fine.

Regression Issue

• Select this option if this issue appears to be a regression.

Expected Behavior

Create a TAG specificatio

Current Behavior

InvalidOperation: You cannot call a method on a null-valued expression

Reproduction Steps

Import-Module -Name AWS.Tools.EC2
$tag = New-Object Amazon.EC2.Model.Tag
$tag.Key = "Name"
$tag.Value = "MyEC2Instance"
$tagSpec = New-Object Amazon.EC2.Model.TagSpecification
$tagSpec.ResourceType = "instance"
$tagSpec.Tags.Add($tag)

Possible Solution

No response

Additional Information/Context

No response

AWS Tools for PowerShell version used

5.0.17

PowerShell version used

the same issue for 5.1 and 7.5.2

Operating System and version

Windows Server 2022

[PetrMa]

I fixed the script by adding the new line.
Is there something what changed in new AWS PS modules?

$tagspec = new-object Amazon.EC2.Model.TagSpecification
$tagspec.ResourceType = "volume"
$tagSpec.Tags = New-Object 'System.Collections.Generic.List[Amazon.EC2.Model.Tag]'

[ashishdhingra]

@PetrMa Good morning. Thanks for opening the issue. The reason the error InvalidOperation: You cannot call a method on a null-valued expression. is returned is that AWS Tools for PowerShell V5 leverages AWS SDK for .NET V4, which is the new major version with breaking changes. One of the breaking changes is that properties using collections on classes used for making requests and responses will now default to null. Please refer below for more details:

• AWS .NET SDK V4 Development Tracker
• AWS .NET SDK V4 developer guide.
• AWS Tools for PowerShell V5 user guide.

To fallback to AWS SDK for .NET V3 behavior (and hence AWS Tools for PowerShell behavior) of initializing collections, we may use below code before executing the mentioned example:

[Amazon.AWSConfigs]::InitializeCollections = $true

Kindly note that the above code is a global level setting.

The better long-term strategy would be to migrate PowerShell code to V5 behavior, which is to initialize collections manually. For example below:

$tagSpec.Tags = @()

Could you please share if you got the example code from PowerShell API reference documentation or user guide. If yes, then it would be good to update the example to reflect the PowerShell V5 behavior.

Thanks,
Ashish

[PetrMa]

Hello,

thank you for explanation. The fix with $tagSpec.Tags = @() works fine

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