An interesting PowerShell feature is that all errors are collected in an array called $error.

so for example if you throw an error you can echo $error and find it later:

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However the error is also logged even if you catch it. Consider the following code snippet, which I’ve called errorcollectiontest.ps1

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When running the script it outputs nothing, but when we check the errors array we find something interesting:

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What does this matter?

Well if you have a system running PowerShell a convenient way to see if there were errors in the execution of a script is to check the $error array for any errors. However this array will also contain errors that were caught during the execution, which will introduce false-positives.

The PowerShell plugin for Hudson/Jenkins does exactly this, so if you want to use a PowerShell script that catches errors in Hudson/Jenkins the way to prevent false positive build results is to make the following change to the script:

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This will remove the latest occurred error from the list, which just happens to be the error just caused since we entered the catch block.

<p>I’d like to mention <a href="http://johan.andersson.net/" target="_blank">Johan Andersson</a>, in this post, since without him it wouldn’t be written.</p>